JP6074957B2 - Atomic oscillator and electronic equipment - Google Patents

Description

  The present invention relates to an atomic oscillator and an electronic device.

2. Description of the Related Art An atomic oscillator that oscillates based on energy transition of an alkali metal atom such as rubidium or cesium is known (see, for example, Patent Document 1).
Such an atomic oscillator generally includes a gas cell in which an alkali metal is enclosed with a buffer gas, a light emitting element that emits excitation light that excites the alkali metal in the gas cell, and a light receiving element that detects excitation light that has passed through the gas cell. Prepare.

Conventionally, in such an atomic oscillator, as described in Patent Document 1, for example, a light emitting element, a gas cell, and a light receiving element are stacked in this order, and these are housed in a common package.
By the way, in such an atomic oscillator, it is necessary to maintain the light emitting element and the gas cell at different temperatures from each other in order to exhibit stable oscillation characteristics.

  However, in the conventional atomic oscillator, thermal interference between the light emitting element and the gas cell is likely to occur. For this reason, depending on the environmental temperature, the temperature of the light emitting element and the gas cell may not be maintained at desired temperatures, respectively. . In particular, such a problem related to thermal interference is that, in an atomic oscillator using a quantum interference effect (CPT: Coherent Population Trapping) by two types of light having different wavelengths, the distance between the light emitting element and the gas cell is generally small. , Become prominent.

US Pat. No. 6,320,472

  An object of the present invention is to provide an atomic oscillator that suppresses or prevents thermal interference between a light emitting element and a gas cell and has excellent oscillation characteristics in a wider environmental temperature range.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
[Application Example 1]
The atomic oscillator of the present invention includes a gas cell in which gaseous metal atoms are enclosed,
A light emitting element that emits excitation light that excites the gaseous metal atoms in the gas cell;
A light receiving element for detecting the excitation light transmitted through the gas cell;
A package having a base on which the light emitting element is installed and a lid covering the light emitting element, and housing the light emitting element in an internal space in a reduced pressure state;
A heat dissipating member provided on the outside of the package and dissipating heat of the base ;
A Peltier element that is housed in the package and adjusts the temperature of the light emitting element, and
The light emitting element is characterized that you have installed in the substrate through the Peltier element.

  According to the atomic oscillator configured as described above, since the inside of the package is depressurized, thermal interference between the outside of the package and the light emitting element can be prevented or suppressed via the lid of the package. Therefore, when the gas cell is disposed outside the package, thermal interference between the light emitting element and the gas cell can be prevented or suppressed, and the temperature of the light emitting element and the gas cell can be independently controlled with high accuracy. Further, even when the light emitting element and the gas cell are housed in the package, by forming a gap between the light emitting element and the gas cell, the gap constitutes a heat insulating layer by decompression, Thermal interference with the gas cell can be prevented or suppressed.

Moreover, since the heat radiating member radiates heat from the base, it is possible to prevent an excessive temperature rise of the light emitting element installed on the base.
The combination of heat insulation by the reduced internal space of the package and heat radiation by the heat radiating member can optimize the heat transfer path between the inside and outside of the package, and can control the temperature of the light emitting element with high accuracy. .
Further, the temperature of the light emitting element can be adjusted by the Peltier element. Further, by installing the light emitting element on the base via the Peltier element, an excessive temperature rise of the Peltier element can be prevented, and as a result, the temperature of the light emitting element can be efficiently adjusted by the Peltier element.
[Application Example 2]
The atomic oscillator of the present invention includes a gas cell in which gaseous metal atoms are enclosed,
A light emitting element that emits excitation light that excites the gaseous metal atoms in the gas cell;
A light receiving element for detecting the excitation light transmitted through the gas cell;
A first package comprising a base body on which the light emitting element is installed and a lid that covers the light emitting element, and constituting a package that houses the light emitting element in an internal space in a reduced pressure state;
A heat dissipating member provided on the outside of the package and dissipating heat of the base;
A second package containing the gas cell and the light receiving element;
And a holding member configured to hold the first package and the second package in a non-contact manner.
As a result, since the light emitting element and the gas cell are housed in separate packages that are not in contact with each other, thermal interference between the light emitting element and the gas cell is prevented or suppressed, and the light emitting element and the gas cell are independently highly accurate. The temperature can be controlled.
Further, since the holding member is made of a non-metal, heat conduction through the holding member between the first package and the second package can be suppressed. As a result, thermal interference between the light emitting element and the gas cell can be effectively prevented or suppressed.

[Application Example 3 ]
The atomic oscillator of the present invention further comprises a Peltier element that is housed in the package and adjusts the temperature of the light emitting element,
The light emitting element is preferably installed on the base via the Peltier element.
Thereby, the temperature of the light emitting element can be adjusted by the Peltier element. Further, by installing the light emitting element on the base via the Peltier element, an excessive temperature rise of the Peltier element can be prevented, and as a result, the temperature of the light emitting element can be efficiently adjusted by the Peltier element.

[Application Example 4]
In the atomic oscillator according to the aspect of the invention, it is preferable that the heat dissipation member has a heat dissipation portion provided outside the holding member.
Thereby, the base | substrate of the 1st package hold | maintained at the holding member can be thermally radiated efficiently.

[Application Example 5]
In the atomic oscillator according to the aspect of the invention, the first package includes a first base that constitutes the base and a first lid that constitutes the lid, and the first lid has a resistance to the excitation light. A transparent window is provided,
The second package includes a second base body on which the gas cell and the light receiving element are installed, a second lid body that covers the gas cell and the light receiving element, and is provided with a window portion that is transmissive to the excitation light. It is preferable to have.
Thereby, the light emitting element and the gas cell can be housed in separate packages that are not in contact with each other while securing the optical path of the excitation light from the light emitting element to the light receiving element via the gas cell.

[Application Example 6]
In the atomic oscillator according to the aspect of the invention, it is preferable that the holding member includes a first support portion that supports the first base and a second support portion that supports the second base.
Thereby, the distance of the contact part of a 1st package and a holding member and the contact part of a 2nd package and a holding member can be enlarged. Therefore, heat conduction through the holding member between the first package and the second package can be more effectively suppressed.

[Application Example 7]
In the atomic oscillator according to the aspect of the invention, it is preferable that the first lid body and the second lid body are not in contact with the holding member.
Thereby, the heat conduction through the holding member between the first package and the second package can be more effectively suppressed.

[Application Example 8]
In the atomic oscillator of the present invention, it is preferable that the heat dissipating member is made of metal.
Thereby, the heat dissipation of a heat radiating member can be made excellent.
[Application Example 9]
In the atomic oscillator of the present invention, it is preferable that the holding member is made of a material having a thermal conductivity of 0.1 W · m ⁻¹ · K ⁻¹ or more and 40 W · m ⁻¹ · K ⁻¹ or less.
Thereby, the heat conduction through the holding member between the first package and the second package can be more effectively suppressed.
[Application Example 10]
An electronic apparatus according to the present invention includes the atomic oscillator according to the present invention.
Thereby, an electronic device with excellent reliability can be provided.

1 is a perspective view showing an atomic oscillator according to a first embodiment of the present invention. It is a schematic diagram which shows schematic structure of the atomic oscillator shown in FIG. It is a figure for demonstrating the energy state of the alkali metal in the gas cell with which the atomic oscillator shown in FIG. 1 was equipped. 2 is a graph showing a relationship between a frequency difference between two lights from a light emitting element and a detection intensity at the light receiving element with respect to the light emitting element and the light receiving element provided in the atomic oscillator shown in FIG. 1. It is a longitudinal cross-sectional view of the atomic oscillator shown in FIG. FIG. 6 is a view (a partially enlarged view of FIG. 5) for explaining a first package and a heat dissipation member of the atomic oscillator shown in FIG. 1. It is a cross-sectional view of the atomic oscillator shown in FIG. It is a longitudinal cross-sectional view of the atomic oscillator which concerns on 2nd Embodiment of this invention. It is a figure which shows schematic structure at the time of using the electronic device of this invention for the positioning system using a GPS satellite. It is a schematic block diagram which shows an example of the clock transmission system using the atomic oscillator of this invention.

Hereinafter, an atomic oscillator and an electronic apparatus of the present invention will be described in detail based on embodiments shown in the accompanying drawings.
<First Embodiment>
1 is a perspective view showing an atomic oscillator according to a first embodiment of the present invention, FIG. 2 is a schematic diagram showing a schematic configuration of the atomic oscillator shown in FIG. 1, and FIG. 3 is provided in the atomic oscillator shown in FIG. FIG. 4 is a diagram for explaining the energy state of the alkali metal in the gas cell, FIG. 4 shows the frequency difference between the two lights from the light emitting element, and the light emitting element and the light receiving element provided in the atomic oscillator shown in FIG. FIG. 5 is a longitudinal sectional view of the atomic oscillator shown in FIG. 1, and FIG. 6 is a diagram for explaining the first package and the heat dissipation member of the atomic oscillator shown in FIG. FIG. 7 (partially enlarged view of FIG. 5) and FIG. 7 are cross-sectional views of the atomic oscillator shown in FIG.

  1 and 5 to 7, for convenience of explanation, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other, and the tip side of each illustrated arrow is the “+ side”. The base end side is defined as “− side”. In the following, for convenience of explanation, a direction parallel to the X axis is referred to as “X axis direction”, a direction parallel to the Y axis is referred to as “Y axis direction”, and a direction parallel to the Z axis is referred to as “Z axis direction”. Further, the + Z direction side (upper side in FIG. 5) is referred to as “upper”, and the −Z direction side (lower side in FIG. 5) is referred to as “lower”.

An atomic oscillator 1 shown in FIG. 1 is an atomic oscillator using a quantum interference effect.
As shown in FIG. 1, the atomic oscillator 1 includes a first unit 2, a second unit 3, optical components 41, 42, 43, a holding member 5 that holds these, and a heat radiating member 7.
Here, as shown in FIGS. 1 and 2, the first unit 2 includes a light emitting element 21, a Peltier element 24, and a first package 22 that houses the light emitting element 21 and the Peltier element 24.

The second unit 3 includes a gas cell 31, a light receiving element 32, a heater 33, a temperature sensor 34, a coil 35, and a second package 36 that houses these.
The first unit 2 and the second unit 3 are driven and controlled by the control unit 6.
First, the principle of the atomic oscillator 1 will be briefly described.

In the atomic oscillator 1, gaseous metal such as rubidium, cesium, and sodium (metal atom) is enclosed in a gas cell 31.
As shown in FIG. 3, the alkali metal has a three-level energy level, and is in three states, two ground states (ground states 1 and 2) having different energy levels, and an excited state. Can take. Here, the ground state 1 is a lower energy state than the ground state 2.

When two types of resonant lights 1 and 2 having different frequencies are irradiated onto such a gaseous alkali metal, the above-described gaseous alkali metal is irradiated with the frequency ω 1 of the resonant light 1 and the frequency ω 2 of the resonant light 2. In accordance with the difference (ω1-ω2), the light absorptivity (light transmittance) of the resonance lights 1 and 2 in the alkali metal changes.
When the difference (ω1−ω2) between the frequency ω1 of the resonant light 1 and the frequency ω2 of the resonant light 2 matches the frequency corresponding to the energy difference between the ground state 1 and the ground state 2, the ground states 1 and 2 Each excitation to the excited state stops. At this time, both the resonant lights 1 and 2 are transmitted without being absorbed by the alkali metal. Such a phenomenon is called a CPT phenomenon or an electromagnetically induced transparency (EIT) phenomenon.
The light emitting element 21 emits two types of light (resonant light 1 and resonant light 2) having different frequencies as described above toward the gas cell 31.

  For example, when the light emitting element 21 fixes the frequency ω1 of the resonant light 1 and changes the frequency ω2 of the resonant light 2, the difference between the frequency ω1 of the resonant light 1 and the frequency ω2 of the resonant light 2 (ω1-ω2). 4 coincides with the frequency ω 0 corresponding to the energy difference between the ground state 1 and the ground state 2, the detection intensity of the light receiving element 32 increases sharply as shown in FIG. Such a steep signal is detected as an EIT signal. This EIT signal has an eigenvalue determined by the type of alkali metal. Therefore, an oscillator can be configured by using such an EIT signal.

Hereinafter, each part of the atomic oscillator 1 will be described in detail sequentially.
(First unit)
As described above, the first unit 2 includes the light emitting element 21, the Peltier element 24 (temperature adjustment element), and the first package 22 that houses the light emitting element 21 and the Peltier element 24.

[Light emitting element]
The light emitting element 21 has a function of emitting excitation light that excites alkali metal atoms in the gas cell 31.
More specifically, the light emitting element 21 emits two types of light (resonant light 1 and resonant light 2) having different frequencies as described above.
The frequency ω1 of the resonant light 1 can excite the alkali metal in the gas cell 31 from the ground state 1 to the excited state.

Further, the frequency ω2 of the resonance light 2 can excite the alkali metal in the gas cell 31 from the ground state 2 to the excited state.
The light emitting element 21 is not particularly limited as long as it can emit the excitation light as described above. For example, a semiconductor laser such as a vertical cavity surface emitting laser (VCSEL) can be used.

Further, the temperature of the light emitting element 21 is adjusted to a temperature different from that of the gas cell 31 described later, for example, about 30 ° C., by a Peltier element 24 (temperature adjusting element) described later.
The light emitting element 21 generates heat as it emits light, but is cooled by the Peltier element 24 or is radiated by the heat radiating member 7 through the base 221 of the first package 22 to be described later. Therefore, even if the light emitting element 21 is housed in the first package 22 having a reduced pressure, as will be described later, it is possible to prevent the light emitting element 21 from being overheated.
Such a light emitting element 21 is electrically connected to a control unit 6 described later.

[Peltier element]
The Peltier element 24 has a function of heating or cooling the light emitting element 21 and adjusting the temperature of the light emitting element 21. Thereby, the characteristic change accompanying the temperature change of the light emitting element 21 can be suppressed or prevented. Therefore, the light emitting element 21 can stably emit the excitation light LL having desired characteristics, and the reliability of the atomic oscillator 1 can be improved.

Further, by controlling the direction of the current flowing in the Peltier element 24, the surface 241 on the light emitting element 21 side of the Peltier element 24 can be switched between the heat generating surface and the heat absorbing surface. Therefore, even if the range of environmental temperature is wide, the light emitting element 21 can be adjusted to a desired temperature (for example, about 30 ° C.).
The Peltier element 24 is driven and controlled based on a detection result of a temperature sensor (not shown) that detects the temperature of the light emitting element 21.

Further, as will be described in detail later, the Peltier element 24 can prevent the entire Peltier element 24 from being overheated by heat radiation by the heat radiation member 7 through the base 221 of the first package 22 described later. Therefore, the temperature of the heat absorbing surface of the Peltier element 24 can be lowered, and as a result, the Peltier element 24 can efficiently adjust the temperature of the light emitting element 21.
Such a Peltier element 24 is electrically connected to a control unit 6 (temperature control unit 64) described later.
Note that the Peltier element 24 may be omitted. In addition, a heater (heating resistor) can be provided as a temperature adjusting element for adjusting the temperature of the light emitting element 21 instead of the Peltier element 24.

[First package]
As shown in FIG. 6, the first package 22 (package) has an internal space S that houses the light emitting element 21 and the Peltier element 24 described above.
As shown in FIG. 5, the first package 22 includes a base 221 (first base) and a lid 222 (first lid). Thereby, the internal space S is formed.

The base 221 supports the light emitting element 21 directly or indirectly. In the present embodiment, the base body 221 has a plate shape and a circular shape in plan view.
The base 221 is radiated by a heat radiating member 7 described later. Thereby, excessive temperature rise of the light emitting element 21 and the Peltier element 24 installed on the base 221 can be prevented.
The constituent material of the base 221 is not particularly limited, and for example, a resin material, a metal material, a ceramic material, or the like can be used. In addition, from the viewpoint of increasing the heat dissipation (thermal conductivity) of the base body 221, it is preferable to use a material having excellent thermal conductivity. In addition, when using the material which has electroconductivity, in order to prevent the short circuit of the leads 223 etc. which are mentioned later, a predetermined insulation process is performed. Further, the heat dissipation (thermal conductivity) of the base body 221 can be improved by providing the base body 221 with a thermally conductive columnar body or cylindrical body that penetrates in the thickness direction.

The light emitting element 21 (mounting component) and the Peltier element 24 are installed (mounted) on one surface (mounting surface) of the base 221.
Here, the light emitting element 21 is installed on the base 221 via the Peltier element 24. Thereby, the temperature of the light emitting element 21 can be adjusted by the Peltier element 24. Further, by installing the light emitting element 21 on the base 221 through the Peltier element 24, an excessive temperature rise of the Peltier element 24 is prevented, and as a result, the temperature of the light emitting element 21 is efficiently adjusted by the Peltier element 24. Can do.

In the present embodiment, the light emitting element 21 is bonded to one surface 241 of the Peltier element 24, and the base 221 is bonded to the other surface 242 of the Peltier element 24.
Further, as shown in FIG. 5, a plurality of leads 223 protrude from the other surface of the base 221. The plurality of leads 223 are electrically connected to the light emitting element 21 via wiring (not shown).

A lid body 222 that covers the light emitting element 21 on the base body 221 is bonded to the base body 221.
The lid 222 has a bottomed cylindrical shape with one end opened. In the present embodiment, the cylindrical portion of the lid 222 has a cylindrical shape.
The opening at one end of the lid 222 is closed by the base 221 described above.

A window 23 is provided at the other end of the lid 222, that is, at the bottom opposite to the opening of the lid 222.
The window portion 23 is provided on the optical axis a between the gas cell 31 and the light emitting element 21.
And the window part 23 has transparency with respect to the excitation light mentioned above.
In this embodiment, the window part 23 is comprised with the lens. Thereby, the excitation light LL can be irradiated to the gas cell 31 without waste.

Moreover, the window part 23 has a function which makes the excitation light LL parallel light. Thereby, it is possible to easily and reliably prevent the excitation light LL from being reflected by the inner wall of the gas cell 31. Therefore, resonance of excitation light in the gas cell 31 is preferably generated, and as a result, the oscillation characteristics of the atomic oscillator 1 can be enhanced.
The window 23 is not limited to a lens as long as it has transparency to excitation light, and may be, for example, an optical component other than a lens, or a simple light-transmissive plate member. Also good. Further, the lens having the function as described above may be provided between the first package 22 and the second package 36 as in the optical components 41, 42, and 43 described later.

The constituent material of the lid body 222 other than the window portion 23 is not particularly limited, and for example, ceramic, metal, resin, or the like can be used.
Here, when a portion other than the window portion 23 of the lid 222 is made of a material that is transparent to excitation light, the portion other than the window portion 23 of the lid 222 and the window portion 23 are formed integrally. can do. Further, when the portion other than the window portion 23 of the lid 222 is made of a material that is not transmissive to the excitation light, the portion other than the window portion 23 of the lid 222 and the window portion 23 are separated. These may be formed and bonded by a known bonding method.

Moreover, it is preferable that the base body 221 and the lid 222 are airtightly joined. That is, it is preferable that the inside of the first package 22 is an airtight space. Thereby, the inside of the 1st package 22 can be made into a pressure reduction state.
The method for joining the base 221 and the lid 222 is not particularly limited, and for example, brazing, seam welding, energy beam welding (laser welding, electron beam welding, etc.), and the like can be used.

  The internal space S formed by the base body 221 and the lid 222 is decompressed. Therefore, due to the heat insulation of the internal space S, thermal interference between the outside of the first package 22 and the light emitting element 21 can be prevented or suppressed via the lid 222 of the first package 22. Therefore, when the gas cell 31 is disposed outside the first package 22 as in the present embodiment, thermal interference between the light emitting element 21 and the gas cell 31 is prevented or suppressed, and the light emitting element 21 and the gas cell 31 are made independent. Thus, the temperature can be controlled with high accuracy.

The pressure in the internal space S is not particularly limited as long as it is equal to or lower than atmospheric pressure, but is preferably about 10 ⁻¹ Pa, for example.
A joining member for joining these may be interposed between the base 221 and the lid 222.
The first package 22 may contain components other than the light emitting element 21 and the Peltier element 24 described above, such as a temperature sensor and an optical component.

According to the first package 22 configured to include the base body 221 and the lid body 222 as described above, the first light emitting element 21 is arranged while allowing the excitation light to be emitted from the light emitting element 21 to the outside of the first package 22. It can be stored in the package 22.
Further, the first package 22 is held by a holding member 5 to be described later so that the base 221 is disposed on the side opposite to the second package 36.

(Second unit)
As described above, the second unit 3 includes the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, the coil 35, and the second package 36 that houses them.
[Gas cell]
The gas cell 31 is filled with gaseous alkali metals such as rubidium, cesium, and sodium.

For example, although not shown, the gas cell 31 includes a main body portion having a columnar through hole and a pair of window portions that block both openings of the through hole. Thereby, the internal space in which the alkali metal is enclosed as described above is formed.
Here, each window part of the gas cell 31 has the permeability | transmittance with respect to the excitation light from the light emitting element 21 mentioned above. One of the windows transmits the excitation light incident into the gas cell 31, and the other window transmits the excitation light emitted from the gas cell 31.

Therefore, the material constituting the window portion of the gas cell 31 is not particularly limited as long as it has transparency to the excitation light as described above, and examples thereof include glass materials and quartz.
Moreover, the material which comprises the main-body part of the gas cell 31 is not specifically limited, A metal material, a resin material, etc. may be sufficient and a glass material, a crystal | crystallization, etc. may be sufficient like a window part.

And each window part is airtightly joined with respect to the main-body part. Thereby, the internal space of the gas cell 31 can be made into an airtight space.
The method for joining the main body portion and the window portion of the gas cell 31 is determined according to these constituent materials and is not particularly limited. For example, a joining method using an adhesive, a direct joining method, an anodic joining method, etc. Can be used.
Further, the temperature of the gas cell 31 is adjusted by the heater 33 to a temperature different from that of the light emitting element 21 described above, for example, about 70 ° C.

[Light receiving element]
The light receiving element 32 has a function of detecting the intensity of the excitation light LL (resonant light 1 and 2) transmitted through the gas cell 31.
The light receiving element 32 is not particularly limited as long as it can detect the excitation light as described above. For example, a photodetector (light receiving element) such as a solar cell or a photodiode can be used.

[heater]
The heater 33 has a function of heating the above-described gas cell 31 (more specifically, an alkali metal in the gas cell 31). Thereby, the alkali metal in the gas cell 31 can be maintained in a gaseous state.
The heater 33 generates heat when energized. For example, the heater 33 includes a heating resistor provided on the outer surface of the gas cell 31. Such a heating resistor is formed using, for example, a chemical vapor deposition method (CVD) such as plasma CVD or thermal CVD, a dry plating method such as vacuum deposition, a sol-gel method, or the like.

Here, when the heating resistor is provided in the incident portion or the emitting portion of the excitation light of the gas cell 31, a material having transparency to the excitation light, specifically, for example, ITO (Indium Tin Oxide), IZO (IZO ( Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and transparent electrode materials such as oxides such as Al-containing ZnO.

The heater 33 is not particularly limited as long as it can heat the gas cell 31, and may be non-contact with the gas cell 31. Further, the gas cell 31 may be heated using a Peltier element instead of the heater 33 or in combination with the heater 33.
Such a heater 33 is electrically connected to a temperature control unit 62 of the control unit 6 described later and energized.

[Temperature sensor]
The temperature sensor 34 detects the temperature of the heater 33 or the gas cell 31. Based on the detection result of the temperature sensor 34, the amount of heat generated by the heater 33 is controlled. Thereby, the alkali metal atom in the gas cell 31 can be maintained at a desired temperature.

The installation position of the temperature sensor 34 is not particularly limited, and may be, for example, on the heater 33 or on the outer surface of the gas cell 31.
The temperature sensor 34 is not particularly limited, and various known temperature sensors such as a thermistor and a thermocouple can be used.
Such a temperature sensor 34 is electrically connected to a temperature control unit 62 of the control unit 6 which will be described later via a wiring (not shown).

[coil]
The coil 35 has a function of generating a magnetic field when energized. Thereby, by applying a magnetic field to the alkali metal in the gas cell 31, a gap between different energy levels in which the alkali metal is degenerated can be widened by Zeeman splitting to improve resolution. As a result, the accuracy of the oscillation frequency of the atomic oscillator 1 can be increased.

The magnetic field generated by the coil 35 may be either a DC magnetic field or an AC magnetic field, or may be a magnetic field in which a DC magnetic field and an AC magnetic field are superimposed.
The installation position of the coil 35 is not particularly limited and is not shown. For example, the coil 35 may be wound around the outer periphery of the gas cell 31 so as to constitute a solenoid type, or may constitute a Helmholtz type. A pair of coils may be opposed to each other via the gas cell 31.

The coil 35 is electrically connected to a magnetic field control unit 63 of the control unit 6 described later via a wiring (not shown). Thereby, the coil 35 can be energized.
The constituent material of the coil 35 is not particularly limited, and examples thereof include silver, copper, palladium, platinum, gold, and alloys thereof, and one or a combination of two or more of these may be used. Can be used.

[Second package]
The second package 36 houses the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 described above.
The second package 36 is configured in the same manner as the first package 22 of the first unit 2 described above.

Specifically, as shown in FIG. 5, the second package 36 includes a base 361 (second base) and a lid 362 (second lid).
The base 361 directly or indirectly supports the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35. In the present embodiment, the base body 361 has a plate shape, and has a circular shape in plan view.

  The gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 (a plurality of mounting parts) are installed (mounted) on one surface (mounting surface) of the base 361. Further, as shown in FIG. 5, a plurality of leads 363 protrude from the other surface of the base 361. The plurality of leads 363 are electrically connected to the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 through a wiring (not shown).

A lid 362 that covers the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 on the base 361 is joined to the base 361.
The lid body 362 has a bottomed cylindrical shape with one end opened. In the present embodiment, the cylindrical part of the lid 362 has a cylindrical shape.
The opening at one end of the lid 362 is closed by the base 361 described above.

A window 37 is provided at the other end of the lid 362, that is, at the bottom opposite to the opening of the lid 362.
The window portion 37 is provided on the optical axis a between the gas cell 31 and the light emitting element 21.
And the window part 37 has transparency with respect to the excitation light mentioned above.
In this embodiment, the window part 37 is comprised with the plate-shaped member which has a light transmittance.

The window portion 37 is not limited to a light-transmitting plate member as long as it has transparency to excitation light. For example, the window portion 37 is an optical component such as a lens, a polarizing plate, or a λ / 4 wavelength plate. May be.
The constituent material other than the window portion 37 of the lid 362 is not particularly limited, and for example, ceramic, metal, resin, or the like can be used.

  Here, when the portion other than the window portion 37 of the lid 362 is made of a material that is transparent to excitation light, the portion other than the window portion 37 of the lid 362 and the window portion 37 are formed integrally. can do. Moreover, when parts other than the window part 37 of the cover body 362 are comprised with the material which does not have a transmittance | permeability with respect to excitation light, parts other than the window part 37 and the window part 37 of the cover body 362 are separated. These may be formed and bonded by a known bonding method.

The base 361 and the lid 362 are preferably joined in an airtight manner. That is, it is preferable that the inside of the second package 36 is an airtight space. Thereby, the inside of the 2nd package 36 can be made into a pressure reduction state or an inert gas enclosure state, As a result, the characteristic of the atomic oscillator 1 can be improved.
The method for joining the base 361 and the lid 362 is not particularly limited, and for example, brazing, seam welding, energy beam welding (laser welding, electron beam welding, etc.), and the like can be used.

Note that a bonding member for bonding them may be interposed between the base 361 and the lid 362.
Further, at least the gas cell 31 and the light receiving element 32 need only be accommodated in the second package 36, and components other than the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 described above are accommodated. May be.

According to the second package 36 having the base 361 and the lid 362 as described above, the gas cell 31 and the light receiving element are allowed while allowing the excitation light from the light emitting element 21 to enter the second package 36. 32 can be stored in the second package 36. Therefore, by using the second package 36 in combination with the first package 22 as described above, the light emitting element 21 and the gas cell are secured while securing the optical path of the excitation light from the light emitting element 21 to the light receiving element 32 via the gas cell 31. 31 can be stored in separate packages that are not in contact with each other.
The second package 36 is held by a holding member 5 described later so that the base 361 is disposed on the side opposite to the first package 22.

(Optical parts)
A plurality of optical components 41, 42, 43 are arranged between the first package 22 and the second package 36 as described above. The plurality of optical components 41, 42, and 43 are provided on the optical axis a between the light emitting element 21 in the first package 22 and the gas cell 31 in the second package 36 described above, respectively. .

In this embodiment, the optical component 41, the optical component 42, and the optical component 43 are arranged in this order from the first package 22 side to the second package 36 side.
The optical component 41 is a λ / 4 wavelength plate. Thereby, for example, when the excitation light from the light emitting element 21 is linearly polarized light, the excitation light can be converted into circularly polarized light (right circularly polarized light or left circularly polarized light).

  As described above, in the state where the alkali metal atoms in the gas cell 31 are Zeeman split by the magnetic field of the coil 35, if the alkali metal atoms are irradiated with excitation light of linearly polarized light, the interaction between the excitation light and the alkali metal atoms causes an alkali. This means that metal atoms are evenly distributed in a plurality of levels where Zeeman splits. As a result, the number of alkali metal atoms at a desired energy level is relatively small with respect to the number of alkali metal atoms at other energy levels, so that the number of atoms that develop a desired EIT phenomenon is reduced and desired. As a result, the oscillation characteristic of the atomic oscillator 1 is deteriorated.

  On the other hand, when the alkali metal atom is irradiated with the circularly polarized excitation light in the state where the alkali metal atom in the gas cell 31 is Zeeman split by the magnetic field of the coil 35 as described above, the interaction between the excitation light and the alkali metal atom. Thus, the number of alkali metal atoms having a desired energy level among the plurality of levels in which the alkali metal atom is Zeeman split can be relatively increased with respect to the number of alkali metal atoms having other energy levels. . Therefore, the number of atoms that express the desired EIT phenomenon increases and the desired EIT signal increases, and as a result, the oscillation characteristics of the atomic oscillator 1 can be improved.

In the present embodiment, the optical component 41 has a disk shape. Therefore, the optical component 41 can be rotated around an axis parallel to the optical axis a while being engaged with a groove 511 having a shape as described later. In addition, the planar view shape of the optical component 41 is not limited to this, For example, depending on the cross-sectional shape of the recessed part 51 of the holding member 5 mentioned later, you may comprise polygons, such as a rectangle and a pentagon.
Optical components 42 and 43 are arranged on the second unit 3 side with respect to such an optical component 41.

  Each of the optical components 42 and 43 is a neutral density filter (ND filter). As a result, the intensity of the excitation light LL incident on the gas cell 31 can be adjusted (decreased). Therefore, even when the output of the light emitting element 21 is large, the excitation light incident on the gas cell 31 can be set to a desired light amount. In the present embodiment, the optical components 42 and 43 adjust the intensity of the excitation light converted into circularly polarized light by the optical component 41 described above.

In the present embodiment, the optical components 42 and 43 each have a plate shape. Moreover, the planar view shapes of the optical components 42 and 43 are each rectangular.
In addition, the planar view shape of the optical components 42 and 43 is not limited to this, For example, you may comprise circular. When the planar view shape of the optical components 42 and 43 is circular, the optical components 42 and 43 can be rotated around an axis parallel to the optical axis a while being engaged with grooves 512 and 513 having shapes as described later. it can.

The optical component 42 and the optical component 43 may have the same or different dimming ratio.
Moreover, the optical components 42 and 43 may have portions where the light attenuation rates are different continuously or stepwise on the upper side and the lower side, respectively. In this case, the attenuation ratio of the excitation light can be adjusted by adjusting the positions of the optical components 42 and 43 in the vertical direction with respect to the holding member 5.

In addition, when the optical components 42 and 43 are rotatable about the axis parallel to the optical axis a in a state where the optical components 42 and 43 are engaged with the grooves 512 and 513, the optical components 42 and 43 are continuously or intermittently in the circumferential direction, respectively. May have portions having different light attenuation rates. In this case, the attenuation ratio of the excitation light can be adjusted by rotating the optical components 42 and 43.
One of the optical components 42 and 43 may be omitted. Moreover, when the output of the light emitting element 21 is moderate, both of the optical components 42 and 43 can be omitted. Further, the optical components 41, 42, 43 are not limited to those described above. For example, at least one of the optical components 41, 42 may be a polarizing plate. In this case, the optical component 43 is preferably a λ / 4 wavelength plate.

(Holding member)
The holding member 5 has a function of holding the first package 22, the second package 36, and the plurality of optical components 41, 42, 43 described above.
The holding member 5 holds the first package 22 and the second package 36 without contacting each other.

Thereby, thermal interference between the light emitting element 21 and the gas cell 31 can be prevented or suppressed, and the temperature control of the light emitting element 21 and the gas cell 31 can be independently performed with high accuracy.
The holding member 5 is made of a nonmetal.
Thereby, the heat conduction through the holding member 5 between the first package 22 and the second package 36 can be suppressed. As a result, thermal interference between the light emitting element 21 and the gas cell 31 can be effectively prevented or suppressed.

If it demonstrates concretely, as shown in FIG. 5, the holding member 5 has the recessed part 51 opened to upper side.
In the recess 51, the first package 22, the second package 36, and a plurality of optical components 41, 42, and 43 are installed. In the present embodiment, the lower portions of the first package 22, the second package 36, and the plurality of optical components 41, 42, 43 are respectively located in the recesses 51.

  The recess 51 has a shape that regulates the positions and postures of the first package 22 and the second package 36. Thereby, the optical system including the light emitting element 21 and the light receiving element 32 can be positioned by installing the first package 22 and the second package 36 in the recess 51 of the holding member 5. Therefore, the installation of the first package 22 and the second package 36 with respect to the holding member 5 can be facilitated.

Here, the recess 51 extends in the X-axis direction, the first package 22 is disposed on one end side (left side in FIG. 5), and on the other end side (right side in FIG. 5). The second package 36 is disposed.
In addition, the first package 22 and the second package 36 are arranged so that the axis of the cylindrical lid body 222 and the lid body 362 are parallel to the extending direction of the recess 51 (X-axis direction). Thereby, the first package 22 and the second package 36 are arranged such that the axes of the lid 222 and the lid 362 are aligned or parallel to each other.

In this embodiment, the cross section of the recess 51 is rectangular.
Further, a support portion 52 (first support portion) that supports the base 221 of the first package 22 is provided on one end portion side (left side in FIG. 5) of the holding member 5, and the other end portion ( On the right side in FIG. 5, a support portion 53 (second support portion) that supports the base body 361 of the second package 36 is provided.

  As described above, the support portion 52 supports the base body 221 and the support portion 53 supports the base body 361, so that the contact portion between the first package 22 and the holding member 5, the second package 36, and the holding member 5 The distance from the contact portion can be increased. Therefore, heat conduction through the holding member 5 between the first package 22 and the second package 36 can be more effectively suppressed.

  Further, the lid body 222 and the lid body 362 are not in contact with the holding member 5. Thereby, the heat conduction through the holding member 5 between the first package 22 and the second package 36 can be more effectively suppressed. In particular, the cross section of the recess 51 is rectangular, whereas the cylindrical portions of the lids 222 and 362 are respectively cylindrical, so that the comparison is made between the side surfaces of the lids 222 and 362 and the holding member 5. Large gaps can be formed. As a result, heat conduction from the lids 222 and 362 to the holding member 5 can be suppressed to an extremely low level. Even if the side surfaces of the lids 222 and 362 and the holding member 5 are in contact with each other, the contact area can be reduced.

  Here, the support part 52 has an installation surface parallel to the Y axis and the Z axis. The surface opposite to the lid 222 of the base body 221 of the first package 22 is in contact with or close to the installation surface. Thereby, the position and attitude | position of the 1st package 22 with respect to the holding member 5 can be controlled. The base body 221 can be fixed to the support portion 52 using an adhesive, for example.

  Further, the support portion 52 is formed with a plurality of through holes 521 through which the plurality of leads 223 of the first package 22 described above are inserted. That is, the support part 52 has a shape like a socket to which the first package 22 is attached. Also by this, the position and posture of the first package 22 with respect to the holding member 5 can be regulated. The plurality of leads 223 can be fixed to the support portion 52 with, for example, solder.

The plurality of leads 223 are inserted into the plurality of through-holes 521, and a plurality of wirings (not shown) are connected to a plurality of terminals (not shown) provided on the lower surface or side surface of the outer surface of the holding member 5. Electrically connected.
Further, the support portion 52 is provided with a heat receiving portion 71 of the heat radiating member 7 described later. Then, the base body 221 of the first package 22 installed on the support portion 52 contacts the heat receiving portion 71. Thereby, the base 221 can be radiated by the heat radiating member 7.

  Similarly, the support part 53 has an installation surface parallel to the Y axis and the Z axis. The surface opposite to the lid 362 of the base body 361 of the second package 36 is in contact with or close to this installation surface. Thereby, the position and attitude | position of the 2nd package 36 with respect to the holding member 5 can be controlled. Note that the base 361 can be fixed to the support 53 using an adhesive, for example.

  Further, the support portion 53 is formed with a plurality of through holes 531 through which the plurality of leads 363 of the second package 36 described above are inserted. That is, the support portion 53 has a shape like a socket to which the second package 36 is attached. Also by this, the position and posture of the second package 36 with respect to the holding member 5 can be regulated. The plurality of leads 363 can be fixed to the support portion 53 by, for example, solder.

Further, the plurality of leads 363 are inserted into the plurality of through holes 531, whereby a plurality of wires (not shown) are connected to a plurality of terminals (not shown) provided on the lower surface or the side surface of the outer surface of the holding member 5. ) Through an electrical connection.
As described above, the holding member 5 holds the first package 22 and the second package 36.

Further, as described above, the holding member 5 holds the optical components 41, 42, and 43, respectively. Thereby, when attaching each component to the holding member 5 at the time of manufacturing the atomic oscillator 1, the optical components 41, 42, and 43 are moved to their positions or in a state where the first package 22 and the second package 36 are held by the holding member 5. It can be installed on the holding member 5 while adjusting its posture.
Specifically, a groove 511 that holds the optical component 41, a groove 512 that holds the optical component 42, and a groove 513 that holds the optical component 43 are formed on the wall surface of the recess 51 of the holding member 5. Yes.

  In the present embodiment, the grooves 511, 512, and 513 are formed so that the plate surfaces of the optical components 41, 42, and 43 are parallel to each other. The grooves 511, 512, and 513 are formed such that the plate surfaces of the optical components 41, 42, and 43 are perpendicular to the optical axis a. The grooves 511, 512, and 513 may be formed such that the plate surfaces of the optical components 41, 42, and 43 are not parallel to each other, and the plate surfaces of the optical components 41, 42, and 43 are respectively optical axes a. It may be formed so as to be inclined with respect to.

The groove 511 can rotatably hold the optical component 41 around an axis (for example, the optical axis a) along a line segment connecting the first package 22 and the second package 36. Accordingly, the posture of the optical component 41 around the optical axis a can be adjusted in a state where the optical component 41 is engaged with the groove 511 of the holding member 5 and positioned in a direction parallel to the optical axis a.
Here, since the optical component 41 is a λ / 4 wavelength plate as described above, the posture of the optical component 41 is adjusted by rotation as shown in FIG. 7 regardless of the posture of the first package 22 with respect to the holding member 5. Thus, the excitation light from the light emitting element 21 can be converted from linearly polarized light to circularly polarized light.
Further, since the optical component 41 has a disk shape, the optical component 41 comes into contact with the wall surface of the concave portion 51 having a rectangular cross section at three places. Thereby, the optical component 41 can be positioned with respect to the holding member 5.

When installing the optical components 41, 42, 43 on the holding member 5, for example, first, the first unit 2 and the second unit 3 are first installed and fixed on the holding member 5. After that, with the optical components 41, 42, 43 engaged with the corresponding grooves 511, 512, 513, while checking the EIT signal, etc., the position and orientation of each optical component 41, 42, 43 Change at least one. When the desired EIT signal is confirmed, the optical components 41, 42, 43 are fixed to the holding member 5 in that state. Such fixing is not particularly limited, but for example, it is preferable to use a photocurable adhesive. The photo-curing adhesive can change the position or posture of each optical component 41, 42, 43 even if it is supplied to each groove 511, 512, 513 before curing, and in a short time when desired. Can be fixed by curing.
The constituent material of the holding member 5 is not particularly limited as long as it is a non-metallic material, and examples thereof include a resin material and a ceramic material.

  Although it does not specifically limit as resin material which comprises the holding member 5, For example, polyolefin, such as polyethylene and ethylene-vinyl acetate copolymer (EVA), acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS resin) , Acrylonitrile-styrene copolymer (AS resin), polyethylene terephthalate (PET), polyether, polyether ketone (PEK), polyether ether ketone (PEEK), styrene, polyolefin, polyvinyl chloride, polyurethane, Various thermoplastic elastomers such as polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber, and chlorinated polyethylene, epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester, Examples thereof include corn resin, polyurethane and the like, and copolymers, blends, polymer alloys and the like mainly containing these, and one or more of these are used in combination (for example, as a laminate of two or more layers). be able to.

  Further, the ceramic material constituting the holding member 5 is not particularly limited. For example, various glasses, and oxide ceramics such as alumina, silica, titania, zirconia, yttria, calcium phosphate, silicon nitride, aluminum nitride, Nitride ceramics such as titanium nitride and boron nitride; carbide ceramics such as graphite and tungsten carbide; and other ferroelectric materials such as barium titanate, strontium titanate, PZT, PLZT, and PLLZT .

In addition, the thermal conductivity of the holding member 5 is preferably 0.1 W · m ⁻¹ · K ⁻¹ or more and 40 W · m ⁻¹ · K ⁻¹ or less, and 0.1 W · m ⁻¹ · K ^−1. More preferably, it is 0.5 W · m ⁻¹ · K ⁻¹ or less. Thereby, the heat conduction through the holding member 5 between the first package 22 and the second package 36 can be more effectively suppressed. That is, the heat insulating property of the holding member 5 can be improved, and the effect of thermally separating the first package 22 and the second package 36 can be made remarkable.

  On the other hand, when the thermal conductivity is too low, it is difficult to select a material that can secure the rigidity necessary for the holding member 5 depending on the shape, size, and the like of the holding member 5, while the thermal conductivity is too high. In this case, depending on the distance between the contact portion between the first package 22 and the holding member 5 and the contact portion between the second package 36 and the holding member 5, the holding member 5 between the first package 22 and the second package 36. It is difficult to suppress heat conduction through

[Heat dissipation member]
The heat radiating member 7 is provided outside the first package 22 and has a function of radiating heat from the base body 221 of the first package 22 described above. Thereby, excessive temperature rise of the light emitting element 21 and the Peltier element 24 installed on the base 221 can be prevented.
In particular, the heat transmission path between the inside and the outside of the first package 22 is optimized by combining the heat insulation by the reduced internal space S of the first package 22 and the heat radiation by the heat radiating member 7 as described above, and light emission. The temperature of the element 21 can be controlled with high accuracy.

More specifically, the light emitting element 21 and the Peltier element 24 housed in the first package 22 are interposed via the lid 222 of the first package 22 due to the heat insulation of the reduced internal space S as described above. Thus, thermal interference between the outside of the first package 22 and the light emitting element 21 can be prevented or suppressed.
On the other hand, even if the light emitting element 21 is not heated by the Peltier element 24, the light emitting element 21 generates heat with light emission. Further, the Peltier element 24 also generates heat as the entire Peltier element 24 is driven, and receives heat from the light emitting element 21, so that the temperature of the entire Peltier element 24 rises.

The heat of the light emitting element 21 and the Peltier element 24 is released to the outside through the base 221 on which the light emitting element 21 and the Peltier element 24 are installed. If the emission is not sufficient, the light emitting element 21 has a temperature higher than a desired temperature. Will also be high.
Moreover, the temperature rise of the whole Peltier element 24 brings about the fall of the temperature control function (especially cooling function) of the Peltier element 24. FIG. As a result, the light emitting element 21 cannot be adjusted to a desired temperature by the Peltier element 24.

Therefore, in the atomic oscillator 1 according to the present invention, the base member 221 is radiated by the heat radiating member 7 to prevent the light emitting element 21 and the Peltier element 24 from being overheated.
The heat radiating member 7 includes a heat receiving portion 71 provided on the support portion 52 of the holding member 5 and a heat radiating portion 72 provided outside the holding member 5.
The heat receiving unit 71 is provided along the installation surface of the support unit 52 (the surface on which the first package 22 is installed). As a result, the heat receiving portion 71 is in contact with the base 221 of the first package 22.

In addition, between the heat receiving part 71 and the base | substrate 221, in order to improve the heat conductivity between these, the heat conductive material which is excellent in insulation and heat conductivity may interpose. Such a heat conductive material is not particularly limited. For example, a material in which a filler excellent in insulation and heat conductivity is dispersed in a resin material can be used.
In the present embodiment, the heat receiving portion 71 has a sheet shape or a plate shape, and a plurality of through holes 711 through which the plurality of leads 223 of the first package 22 are inserted are formed.

Such a heat receiving portion 71 is formed integrally with the heat radiating portion 72. Thereby, the heat receiving part 71 is thermally connected to the heat radiating part 72.
The heat dissipating part 72 is provided outside the holding member 5 (on the side opposite to the recessed part 51). Thereby, the base | substrate 221 of the 1st package 22 hold | maintained at the holding member 5 can be thermally radiated efficiently.

In the present embodiment, the heat radiating portion 72 is provided along the outer surface of the holding member 5. Thereby, the area of the heat radiation surface of the heat radiation part 72 can be increased while suppressing the heat radiation part 72 from protruding from the outer surface of the holding member 5.
In the present embodiment, the heat radiating portion 72 has a sheet shape or a plate shape. Thereby, for example, even if the heat radiation part 72 is provided along the installation surface of the holding member 5, the installation surface can be installed on the substrate.

The heat radiating portion 72 may be provided with fins for improving the heat dissipation. In this case, the heat radiating part 72 may be provided at a site different from the installation surface of the holding member 5 or may be provided with a through hole that prevents contact with the fin on the substrate on which the holding member 5 is installed.
Such a heat radiating member 7 is preferably made of metal. Thereby, the heat dissipation of the heat radiating member 7 can be made excellent. Moreover, when the heat radiating member 7 is comprised with a metal, the heat radiating member 7 can be formed easily and cheaply by bending a metal plate.

Moreover, the heat conductivity of the heat radiating member 7 should just be higher than the heat conductivity of the holding member 5 mentioned above, However, It is preferable that it is as high as possible, Specifically, it is 10W * m ^{< -1} > * K ^<-1 > or more. It is preferably 40 W · m ⁻¹ · K ⁻¹ or more, more preferably 100 W · m ⁻¹ · K ⁻¹ or more.
From such a point of view, it is preferable to use a metal material as the constituent material of the heat radiating member 7 as described above. In particular, for example, aluminum or an alloy thereof, copper or an alloy thereof is preferably used.

[Control unit]
The control unit 6 shown in FIG. 2 has a function of controlling the heater 33, the coil 35, the light emitting element 21, and the Peltier element 24, respectively.
Such a control unit 6 is applied to the excitation light control unit 61 that controls the frequencies of the resonant lights 1 and 2 of the light emitting element 21, the temperature control unit 62 that controls the temperature of the alkali metal in the gas cell 31, and the gas cell 31. A magnetic field control unit 63 that controls the magnetic field to be transmitted, and a temperature control unit 64.

  The excitation light control unit 61 controls the frequencies of the resonant lights 1 and 2 emitted from the light emitting element 21 based on the detection result of the light receiving element 32 described above. More specifically, the excitation light control unit 61 uses the resonance light emitted from the light emitting element 21 so that (ω1-ω2) detected by the light receiving element 32 described above becomes the frequency ω0 unique to the alkali metal described above. Control the frequency of 1 and 2. In addition, the excitation light control unit 61 controls the center frequency of the resonant lights 1 and 2 emitted from the light emitting element 21.

Further, the temperature control unit 62 controls energization to the heater 33 based on the detection result of the temperature sensor 34. Thereby, the gas cell 31 can be maintained within a desired temperature range. Here, the temperature sensor 34 constitutes temperature detection means for detecting the temperature of the gas cell 31.
The magnetic field control unit 63 controls energization of the coil 35 so that the magnetic field generated by the coil 35 is constant.
Such a control part 6 is provided in the IC chip mounted on the board | substrate with which the holding member 5 is installed, for example.

  According to the atomic oscillator 1 of the present embodiment as described above, since the inside of the first package 22 is depressurized, the outside of the first package 22, the light emitting element 21, and the like via the lid 222 of the first package 22. It is possible to prevent or suppress the thermal interference between the two. Therefore, when the gas cell 31 is disposed outside the first package 22 as in the present embodiment, thermal interference between the light emitting element 21 and the gas cell 31 is prevented or suppressed, and the light emitting element 21 and the gas cell 31 are made independent. Thus, the temperature can be controlled with high accuracy.

Moreover, since the heat radiating member 7 radiates heat from the base 221, it is possible to prevent an excessive temperature rise of the light emitting element 21 installed on the base 221.
The combination of the heat insulating property by the reduced internal space S of the first package 22 and the heat radiating property of the base 221 by the heat radiating member 7 optimizes the heat transfer path between the inside and the outside of the first package 22 and emits light. The temperature of the element 21 can be controlled with high accuracy. As a result, the characteristics of the atomic oscillator 1 can be improved.

Second Embodiment
Next, a second embodiment of the present invention will be described.
FIG. 8 is a longitudinal sectional view of an atomic oscillator according to the second embodiment of the invention.
The atomic oscillator according to the present embodiment is the same as the atomic oscillator according to the first embodiment described above except that the light emitting element, the gas cell, the light receiving element, and the like are housed in the same package.

In the following description, the atomic oscillator according to the second embodiment will be described with a focus on differences from the first embodiment, and description of similar matters will be omitted. Moreover, in FIG. 8, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.
As shown in FIG. 8, the atomic oscillator 1A shown in FIG. 7 includes a light emitting element 21, a Peltier element 24, a gas cell 31, a light receiving element 32, a heater 33, a package 22A for storing them, and a package 22A. A holding member 5 </ b> A to hold and a heat radiating member 7 are provided. In the present embodiment, the holding member 5A can be omitted.

Although not shown in FIG. 7 for convenience of explanation, the atomic oscillator 1A includes optical components, a temperature sensor, a coil, and the like, as in the atomic oscillator 1 of the first embodiment described above, and these are also included in the package 22A. It is stored.
In the present embodiment, not only the light emitting element 21 and the Peltier element 24 but also the gas cell 31, the light receiving element 32, and the heater 33 are accommodated in the internal space S1 of the package 22A.

The package 22A includes a base 221 and a lid 222A. Thereby, the internal space S1 is formed.
The internal space S1 is decompressed.
Here, the gas cell 31, the light receiving element 32, and the heater 33 are supported by the base 221 through a support member 8 for forming a gap with the light emitting element 21.

Even when the light emitting element 21 and the gas cell 31 are accommodated in the package 22A as in the present embodiment, the gap is formed between the light emitting element 21 and the gas cell 31 so that the gap is thermally insulated by decompression. Since the layer is formed, thermal interference between the light emitting element 21 and the gas cell 31 can be prevented or suppressed.
The atomic oscillator 1A according to the second embodiment as described above can also suppress or prevent thermal interference between the light emitting element and the gas cell, and can exhibit excellent oscillation characteristics in a wider environmental temperature range. .

(Electronics)
The atomic oscillator as described above can be incorporated into various electronic devices. Such an electronic device can exhibit excellent reliability.
Hereinafter, the electronic apparatus of the present invention will be described.
FIG. 9 is a system configuration schematic diagram when the atomic oscillator of the present invention is used in a positioning system using a GPS satellite.

The positioning system 100 shown in FIG. 9 includes a GPS satellite 200, a base station device 300, and a GPS receiving device 400.
The GPS satellite 200 transmits positioning information (GPS signal).
The base station device 300 receives the positioning information from the GPS satellite 200 with high accuracy via, for example, an antenna 301 installed at an electronic reference point (GPS continuous observation station), and the reception device 302 receives the positioning information. And a transmission device 304 that transmits positioning information via the antenna 303.

Here, the receiving device 302 is an electronic device provided with the above-described atomic oscillator 1 of the present invention as its reference frequency oscillation source. Such a receiving apparatus 302 has excellent reliability. In addition, the positioning information received by the receiving device 302 is transmitted by the transmitting device 304 in real time.
The GPS receiver 400 includes a satellite receiver 402 that receives positioning information from the GPS satellite 200 via the antenna 401, and a base station receiver 404 that receives positioning information from the base station device 300 via the antenna 403. Prepare.

FIG. 10 is a schematic configuration diagram showing an example of a clock transmission system using the atomic oscillator of the present invention.
A clock transmission system 500 shown in FIG. 10 is a system that matches clocks of respective devices in a time division multiplexing network and has a redundant configuration of N (Normal) and E (Emergency) systems.

The clock transmission system 500 includes a clock supply device (CSM: Clock Supply Module) 501 and an SDH (Synchronous Digital Hierarchy) device 502 of station A (upper (N system)), and a clock of station B (upper (E system)). A supply device 503 and an SDH device 504, and a clock supply device 505 and SDH devices 506 and 507 of a station C (lower level) are provided.
The clock supply device 501 has an atomic oscillator 1 and generates an N-system clock signal. The atomic oscillator 1 in the clock supply device 501 generates a clock signal in synchronization with higher-precision clock signals from master clocks 508 and 509 including an atomic oscillator using cesium.

The SDH device 502 transmits and receives the main signal based on the clock signal from the clock supply device 501, superimposes the N-system clock signal on the main signal, and transmits it to the lower clock supply device 505.
The clock supply device 503 includes the atomic oscillator 1 and generates an E-system clock signal. The atomic oscillator 1 in the clock supply device 503 generates a clock signal in synchronization with higher-precision clock signals from master clocks 508 and 509 including an atomic oscillator using cesium.

The SDH device 504 transmits and receives the main signal based on the clock signal from the clock supply device 503, superimposes the E-system clock signal on the main signal, and transmits it to the lower clock supply device 505.
The clock supply device 505 receives the clock signals from the clock supply devices 501 and 503, and generates a clock signal in synchronization with the received clock signals.

  Here, the clock supply device 505 normally generates a clock signal in synchronization with the N-system clock signal from the clock supply device 501. When an abnormality occurs in the N system, the clock supply device 505 generates a clock signal in synchronization with the E system clock signal from the clock supply device 503. By switching from the N system to the E system in this way, stable clock supply can be ensured and the reliability of the clock path network can be improved.

The SDH device 506 transmits and receives the main signal based on the clock signal from the clock supply device 505. Similarly, the SDH device 507 transmits and receives the main signal based on the clock signal from the clock supply device 505. As a result, the C station apparatus can be synchronized with the A station or B station apparatus.
Although the atomic oscillator and the electronic device of the present invention have been described based on the illustrated embodiments, the present invention is not limited to these.
Moreover, in the atomic oscillator and the electronic device of the present invention, the configuration of each part can be replaced with an arbitrary configuration that exhibits the same function, and an arbitrary configuration can be added.
Moreover, you may make it the atomic oscillator of this invention combine the arbitrary structures of each embodiment mentioned above.

In the above-described embodiment, the case where the Peltier element (temperature adjustment element) is interposed between the light emitting element and the base of the package has been described as an example. However, the present invention is not limited to this. May be installed directly on the substrate of the package.
Further, the form of the holding member that holds the package is not limited to that of the above-described embodiment, and may be, for example, a substrate having a circuit that controls each part of the atomic oscillator. In this case, for example, a through hole into which a package or the like is inserted may be formed in such a substrate.

  DESCRIPTION OF SYMBOLS 1 ...... Atomic oscillator 1A ... Atomic oscillator 2 ... 1st unit 3 ... 2nd unit 5 ... Holding member 5A ... Holding member 6 ... Control part 7 ... Radiating member 8 ... Supporting member 21 ... Light emitting element 22 ... 1st package (package) 22A ... Package 23 ... Window part 24 ... Peltier element 31 ... Gas cell 32 ... Light receiving element 33 ... Heater 34 ... Temperature sensor 35 ... Coil 36 ... Package 37 ... Window part 41 ... Optical part 42 ... Optical part 43 ... Optical part 51 ... Recess 52 ... Support part 53 ... Support part 61 ... Excitation light control part 62 ... Temperature control part 63 ... Magnetic field control unit 64 Temperature control unit 71 Heat receiving unit 72 Heat dissipation unit 100 Positioning system 200 GPS satellite 221 Substrate 222 Lid 22A ... lid 223 ... lead 241 ... surface 242 ... surface 300 ... base station device 301 ... antenna 302 ... reception device 303 ... antenna 304 ... transmission device 361 ... base 362 ... lid body 363 ... Lead 400 ... GPS receiver 401 ... Antenna 402 ... Satellite receiver 403 ... Antenna 404 ... Base station receiver 500 ... Clock transmission system 501 ... Clock supply device 502 ... SDH device 503 ... ... Clock supply device 504 ... SDH device 505 ... Clock supply device 506 ... SDH device 507 ... SDH device 508 ... Master clock 509 ... Master clock 511 ... Groove 512 ... Groove 513 ... Groove 521 ... Through hole 531 ... Through hole 711 ... Through hole LL ... Excitation light S ... Internal space S1 Internal space ω0 ... Frequency ω1 ... Frequency ω2 ... Frequency

Claims (10)

A gas cell in which gaseous metal atoms are enclosed;
A light emitting element that emits excitation light that excites the gaseous metal atoms in the gas cell;
A light receiving element for detecting the excitation light transmitted through the gas cell;
A package having a base on which the light emitting element is installed and a lid covering the light emitting element, and housing the light emitting element in an internal space in a reduced pressure state;
A heat dissipating member provided on the outside of the package and dissipating heat of the base ;
A Peltier element that is housed in the package and adjusts the temperature of the light emitting element, and
The light emitting device, an atomic oscillator, characterized that you have installed in the substrate through the Peltier element.   A gas cell in which gaseous metal atoms are enclosed;
  A light emitting element that emits excitation light that excites the gaseous metal atoms in the gas cell;
  A light receiving element for detecting the excitation light transmitted through the gas cell;
  A first package comprising a base body on which the light emitting element is installed and a lid that covers the light emitting element, and constituting a package that houses the light emitting element in an internal space in a reduced pressure state;
  A heat dissipating member provided on the outside of the package and dissipating heat of the base;
  A second package containing the gas cell and the light receiving element;
  An atomic oscillator comprising: a non-metal, and a holding member that holds the first package and the second package in a non-contact manner. A Peltier device that is housed in the package and adjusts the temperature of the light emitting device;
The atomic oscillator according to claim 2 , wherein the light emitting element is installed on the base via the Peltier element. The atomic oscillator according to claim 2 , wherein the heat radiating member has a heat radiating portion provided outside the holding member. The first package includes a first base that constitutes the base and a first lid that constitutes the lid, and the first lid has a window portion that is transmissive to the excitation light. Provided,
The second package includes a second base body on which the gas cell and the light receiving element are installed, a second lid body that covers the gas cell and the light receiving element, and is provided with a window portion that is transmissive to the excitation light. The atomic oscillator according to claim 2, comprising:   The atomic oscillator according to claim 5, wherein the holding member includes a first support part that supports the first base body and a second support part that supports the second base body.   The atomic oscillator according to claim 6, wherein each of the first lid and the second lid is not in contact with the holding member.   The atomic oscillator according to claim 1, wherein the heat dissipation member is made of metal. The atomic oscillator according to claim 2 , wherein the holding member is made of a material having a thermal conductivity of 0.1 W · m ⁻¹ · K ⁻¹ or more and 40 W · m ⁻¹ · K ⁻¹ or less.   An electronic apparatus comprising the atomic oscillator according to claim 1.

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