JP2000028931A - Multiple wavelength filter array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized multiple wavelength filter array which is excellent in a wavelength resolving power with respect to an incident light having plural wavelengths by respectively setting distances separating first and second distributed Bragg reflectors freely variably and contrallably or setting to values different from each other. SOLUTION: A lower-part distributed Bragg reflector (lower-part DBR) 11 as a first distributed Bragg reflector and upper-part distributed Bragg reflector (upper-part DBRs) 12 as second distributed Bragg reflectors separated with air gaps 13 above the first one are integrally formed on an Si substrate 1. A Fabry-Perot interferometer 10 is formed by the lower-part DBR 11 and upper- part DBR 12. The plural pieces of this Fabry-Perot interferometer 10 are arranged linearly on the same Si substrate. Then, a driving means for dividing which respectively variably controls distances separating the lower-part DBR 11 and respective upper-part DBRs 12 independently is provided as an electrostatic actuator having a fixed-side driving electrode 14 and movable-side driving electrodes 15. Thus, wave-lengths of transmission lights of respective Fabry-Perot interferometers 10 can be independently and arbitrarily selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength filter for use in wavelength division multiplexing communication, and more particularly to a Fabry-Perot interferometer comprising a distributed Bragg reflector having a high wavelength resolution, which can be manufactured by silicon micromachining. The structure of a multi-wavelength filter array.

[0002]

2. Description of the Related Art In recent years, wavelength-division multiplexing communication systems have been developed and related technologies have attracted attention, and optical demultiplexers, optical modulators, and photodetectors have become important optical components.

In a wavelength division multiplex communication system, a channel is set for each wavelength, and channel selection is realized by a variable wavelength filter (for example, “Ultra High Speed Optical Switching” published by Baifukan). Wavelength band is 1520-1560n
m, about 10 channels.

In a conventional optical demultiplexer, light emitted from an optical fiber enters a waveguide formed on a quartz substrate, is demultiplexed in the waveguide, and is input to an output optical fiber ( For example, “Wavelength Multiplexer / Demultiplexer Filters in
Glass on Silicon ”, ETHZurich Annual Report 199
7, pp210; hereinafter, the prior art 1). Further, in order to detect the split light, it is connected to a photodiode array as a light receiving element using a ribbon fiber.

By the way, as a method of manufacturing a small-sized wavelength filter, it has been considered to manufacture a Fabry-Perot interferometer using micromachining. For example, "A FABRY-PEROT MICROINTERFEROMETER FOR VISIBL
E WAVELENGTH ”, IEEE, MEMS92, 1992,
PP 170-173 (hereinafter referred to as prior art 2) shows a Fabry-Perot interferometer made by micromachining for light in the visible region. Here, the Fabry-Perot interferometer is a silicon nitride (Si
N) Consists of two mirrors supported by a membrane, each of which has a silicon oxide (SiO ₂ ) film with a refractive index of 1.44 and a HfO film with a refractive index of 1.80.
_It consists of _two multilayer films.

A photodetector using a distributed Bragg reflector as a mirror in a Fabry-Perot interferometer that can continuously tune and detect wavelengths is disclosed in US Pat. No. 5,629,95.
No. 1 (hereinafter, Prior Art 3). Here, the upper side of two distributed Bragg reflectors constituting the Fabry-Perot interferometer is a cantilever, and the gap distance is controlled by electrostatic driving to control the detection wavelength.

With respect to the optical modulator, several studies have been made on an optical modulator using a Fabry-Perot interferometer manufactured by micromachining. For example, U.S. Pat. No. 5,500,761 (hereinafter, Prior Art 4) discloses a micromechanical modulator. This is because a membrane provided via a substrate and an air gap is driven by electrostatic force, and functions as a modulator by changing the reflectance of incident light.

[0008] Also, "PROCESS AND DESIGN CONSIDERATI
ON FOR SURFACE MICROMACHININEDBEAMS FOR A TUNABLE
INTERFEROMATER ARRAY IN SILICON ”, IEEE, ME
MS93, PP230-235 (hereinafter referred to as prior art 5) shows a high-speed optical modulator in which a Fabry-Perot interferometer is integrated on a photodiode. Here, the Fabry-Perot interferometer uses a SiO ₂ / poly-S
i, a membrane made of poly-Si / SiN / poly-Si, and an intermediate air gap.

"MHz OPTO-MECAHNICAL MODULATOR", TRAN
SDUCERS'95. EUROSENSORS, 1995, PP289-
292 (hereinafter, prior art 6) also shows a modulator. Here, a modulation speed of 2.8 Mbit / sec. Is obtained. The Fabry-Perot interferometer is a two-layer parallel poly-
It is made of Si.

[0010]

The prior art 1
As described above, in a duplexer using a waveguide formed on a quartz substrate, it is difficult to reduce the size of the waveguide portion. Also,
It is not integrated with a photodiode as a light receiving element, and it is necessary to fuse and connect to a ribbon fiber to detect light, which is troublesome.

A Fabry-Perot interferometer manufactured by micromachining as shown in the prior art 2 can be used as a wavelength filter, but in order to apply this to a duplexer, the structure for that is examined. Further, it is necessary to improve the wavelength resolution. Further, it is required that the light receiving element be integrated so as to have a light detecting function.

A distributed Bragg reflector as shown in Prior Art 3 was used as a mirror of a Fabry-Perot interferometer.
A photodetector capable of continuously tuning the wavelength can detect light with good wavelength resolution. However, in this case, since the elements are not arranged in an array, no consideration has been given to a duplexer.

On the other hand, the optical modulators shown in the prior arts 4, 5, and 6 are filters that modulate monochromatic light by changing its reflectance or transmittance. Therefore, wavelength resolution is not required, but rather it is desirable to have the same optical characteristics for a plurality of wavelengths. Therefore, a separate duplexer is required.

In view of the above, the present invention provides an input light having a plurality of wavelengths by integrating a Fabry-Perot interferometer comprising a distributed Bragg reflector on a substrate as a wavelength filter and forming an array thereof. An object of the present invention is to provide a compact multi-wavelength filter array having excellent wavelength resolution.

Other objects and novel features of the present invention will be clarified in embodiments described later.

[0016]

In order to achieve the above object, a multi-wavelength filter array according to a first aspect of the present invention comprises a first and second distributed Bragg reflectors integrated on a substrate. A plurality of Perot interferometers are arranged on the substrate, and the distance separating the first and second distributed Bragg reflectors is variably controllable or set to different values.

According to a second aspect of the present invention, there is provided a multi-wavelength filter array comprising a plurality of demultiplexing Fabry-Perot interferometers comprising first and second distributed Bragg reflectors integrated on a first substrate. The first and second substrates are arranged on the first substrate.
The demultiplexing array unit in which the distance separating the distributed Bragg reflectors is set to be variably controllable or different from each other, and the third and fourth distributed Bragg reflectors integrated on the second substrate. A modulation array section comprising a plurality of modulation Fabry-Perot interferometers arranged on the second substrate, and modulation driving means for oscillating the fourth distributed Bragg reflector with a modulation signal. And the demultiplexing array unit is arranged on the light incident side of the modulation array unit.

According to a third aspect of the present invention, there is provided a multi-wavelength filter array according to the first or second aspect, wherein the distance separating the first and second distributed Bragg reflectors is variably controlled independently. Driving means is provided.

According to a fourth aspect of the present invention, there is provided the multi-wavelength filter array according to the first, second or third aspect, wherein the substrate is a germanium substrate, and the Fabry-Perot is formed on a photodiode formed on the germanium substrate. It is an integrated interferometer.

According to a fifth aspect of the present invention, there is provided a multi-wavelength filter array according to the first, second, third or fourth aspect, wherein each of the films constituting the distributed Bragg reflector has a film thickness of each film. Refractive index n, λ (1+
2m) / 4n (where, m: 0 or a natural number), the Fabry - said distributed Bragg reflector distance separating the mutually lambda / 2n ₀ forming the Perot interferometer (where, n _0: the distributed Bragg reflector (The refractive index of the medium that separates the containers).

According to a sixth aspect of the present invention, there is provided the multi-wavelength filter array according to the first, second, third, fourth or fifth aspect.
The distributed Bragg reflector comprises a high-refractive-index silicon nitride film and a low-refractive-index silicon oxide or silicon oxynitride film.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multi-wavelength filter array according to the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a multi-wavelength filter array as a duplexer according to a first embodiment of the present invention. FIG. 1 is a sectional view and FIG. 2 is a schematic perspective view.

In these figures, a lower distributed Bragg reflector (lower DBR) 11 as a first distributed Bragg reflector is provided on a silicon (Si) substrate 1, and an air gap 13 is provided thereon. An upper distributed Bragg reflector (upper DBR) 12 as a second distributed Bragg reflector is sequentially formed, and a Fabry-Perot interferometer 10 is formed by the lower and upper distributed Bragg reflectors 11 and 12. A plurality of Fabry-Perot interferometers 10 are linearly arranged on the same substrate 1.

As shown in FIG. 3, the lower distributed Bragg reflector 11 and the upper distributed Bragg reflector 12 constituting each Fabry-Perot interferometer 10 are made of silicon nitride (SiN) having a refractive index of 2.0. It is composed of a multilayer film in which a plurality of pairs of a film 20 and a silicon oxynitride (SiON) film 21 having a refractive index of 1.5 are formed. The film thickness is λ (1 + 2m) / 4n (where m is 0 or a natural number) with respect to the refractive index n of each film and the center wavelength λ of light to be transmitted.
Is leading from. In addition, distributed Bragg reflectors 11 and 12
The distance separating them is derived from λ / 2n ₀ (where n _{0 is} the refractive index of the medium separating the distributed Bragg reflectors). In the present embodiment, it is the air gap 13 that separates the distributed Bragg reflectors from each other, and the refractive index is 1.

In each Fabry-Perot interferometer 10, the upper distributed Bragg reflector 12 has a membrane structure supported by flexible arms with respect to the lower distributed Bragg reflector 11, and the upper distributed Bragg reflector On the reflector 12, a movable-side drive electrode 15 for attracting this to the substrate side by electrostatic force is formed, and a fixed-side drive electrode 14 as shown in FIG. It is. Therefore, the movable side driving electrode 15 provided on the upper distributed Bragg reflector 12 and the lower distributed Bragg reflector 11
The fixed-side drive electrode 14 provided in the above-mentioned configuration constitutes an electrostatic actuator as drive means for variably controlling a distance between the lower and upper distributed Bragg reflectors 11 and 12, and includes a fixed-side and movable-side drive. By applying a voltage to the electrodes 14 and 15, the upper distributed Bragg reflector 12 can be attracted toward the substrate by electrostatic force to adjust the air gap 13.

As shown in FIG. 2, the Fabry-Perot interferometer 1 integrated in an array on the Si substrate 1
The lens system 3 and one input optical fiber 4 are arranged on the light incident side of the substrate 0, and the number of output optical fibers 5 corresponding to the number of Fabry-Perot interferometers 10 are arranged on the light emitting side of the substrate 1. Since the light transmitted through the substrate 1 is further incident on the output optical fiber 5 on the light receiving side, the substrate 1 is thinned only below the Fabry-Perot interferometer 10, and the output fiber 5 is disposed here.

As shown in FIG. 2, the incident light 6 from the input optical fiber 4 is perpendicularly incident on the array of the Fabry-Perot interferometer 10 as a parallel line using the lens system 3. Distributed Bragg reflector 1 of each Fabry-Perot interferometer 10
As described with reference to FIG. 3, each of the multilayer films 1 and 12 is formed of a multilayer film including the high refractive index film 20 and the low refractive index film 21. With this multilayer structure, it can function as a wavelength filter having a good wavelength resolution. By applying a DC voltage independently between the electrodes 14 and 15 of each Fabry-Perot interferometer 10 arranged in an array, the air gap 13 can be changed for each Fabry-Perot interferometer 10. The center wavelength of the transmitted outgoing light 7 can be controlled. Here, the gap interval t and the wavelength λ of the transmitted light have a relationship of t = λ / 2n ₀ (where n ₀ = 1 in the air gap) with n ₀ being the refractive index. In this case, if the eight Fabry-Perot interferometers 10 are arranged in an array, each output optical fiber 5 receives only the optical signal of the wavelength selected by the corresponding Fabry-Perot interferometer 10 as a wavelength filter. For example, light having wavelengths of λ _{1 to} λ ₈ different from each other can be demultiplexed and function as a demultiplexer as a whole.

FIG. 4 shows the wavelength characteristics of a plurality of Fabry-Perot interferometers 10 integrated on the substrate 1 as an array, and the mirrors of the Fabry-Perot interferometer 10 (lower distributed Bragg reflector 11 and upper distributed Bragg reflector 11). In 12),
The effect of stacking a pair of a film 20 having a high refractive index and a film 21 having a low refractive index is shown. That is, it is confirmed that the wavelength resolution is improved as the number of stacked multilayer films is increased.

FIG. 5 shows the relationship between the transmitted light intensity and the wavelength when the air gap 13 of the Fabry-Perot interferometer 10 is adjusted. Eight points between a wavelength of 1510 nm and 1565 nm, and a gap of 697.5 nm to 806.0 n
It is adjusted by changing up to m. First, from FIG.
It is confirmed that the wavelength filter has a half value width of 2 nm and is excellent in wavelength resolution. It is also confirmed that the wavelength width sufficient to realize multi-channel can be covered.

According to the first embodiment, the following effects can be obtained.

(1) Lower distributed Bragg reflector 11 and upper distributed Bragg reflector 12 sequentially integrated on Si substrate 1
A plurality of Fabry-Perot interferometers 10 are arranged on the same substrate 1, and are distributed Bragg reflectors 11 and 12.
By independently controlling the distances separating the light beams from each other, the light including a plurality of wavelengths incident on the substrate surface can be controlled by each fabric.
-The Perot interferometer 10 can selectively transmit light of any different wavelength, and therefore, a duplexer having excellent wavelength resolution can be miniaturized.

(2) Lower and upper distributed Bragg reflector 1
A branching drive unit that independently and variably controls the distance separating the first and second electrodes 12 and 12 is configured as an electrostatic actuator having a fixed-side drive electrode 14 and a movable-side drive electrode 15. , The wavelength of the transmitted light of each Fabry-Perot interferometer 10 can be independently and arbitrarily selected.

(3) The distributed Bragg reflectors 11 and 12 constituting each Fabry-Perot interferometer 10 have a refractive index of 2.
And a SiON film 21 having a refractive index of 1.5 is formed in a plurality of pairs. The film thickness is determined by the refractive index n of each film and the center wavelength λ of light to be transmitted. On the other hand, λ (1 + 2m) / 4n (where m is 0 or a natural number), and the distance separating the distributed Bragg reflectors 11 and 12 is λ / 2n ₀ (where n ₀ is the mutual distance between the distributed Bragg reflectors). (The refractive index of the medium separating the two), the wavelength resolution can be changed by changing the number of film forming pairs.

(4) The distributed Bragg reflectors 11 and 12
It consists of a high refractive index SiN film and a low refractive index SiON film,
It can be used in the infrared region and can be easily formed by micromachining using a Si substrate.

FIG. 6 shows a second embodiment of the present invention and schematically shows a structure in which a duplexer and a photodetector are integrated. A plurality of PN junction photodiodes 31 are formed on a germanium (Ge) substrate 1, and a Fabry-Perot interferometer 1 including distributed Bragg reflectors 11 and 12 is formed thereon.
0s are integrated and a plurality of arrays are arranged as an array.
The details of the structure of each Fabry-Perot interferometer 10 are the same as those of the first embodiment.

In the second embodiment, as in the first embodiment, the center wavelength of the transmitted light can be arbitrarily controlled by arbitrarily changing the air gap 13 of the Fabry-Perot interferometer 10. Therefore, even if the incident light 6 including a plurality of wavelengths is incident, only the light having the selected center wavelength is detected as an electric signal by the photodiode 31 corresponding to the Fabry-Perot interferometer 10. Therefore, the light detection function can be provided in the same substrate, that is, in the same chip. In addition, since the Fabry-Perot interferometer 10 and the photodiode 31 are arranged in an array, signals can be received in multiple channels.

In the first or second embodiment, the air gap 13 can be replaced with a fixed intermediate layer made of a material having a low refractive index. In that case, the intermediate layer thickness of each Fabry-Perot interferometer 10 is adjusted to a different layer thickness, and the center wavelength of the transmitted light is selected to be different for each Fabry-Perot interferometer 10.

FIG. 7 shows a third embodiment, schematically showing a structure in which a duplexer, a photodetector and a modulator are integrated. However, FIG. 7 shows one element extracted from an array in which a plurality of elements are arranged. The device shown in FIG. 7 includes a demultiplexing fabric comprising first and second (lower and upper) distributed Bragg reflectors 11 and 12 on a Si substrate 1.
-A demultiplexing array unit 40 having the same structure as that of the first embodiment in which the Perot interferometer 10 is integrated as an array, and a PN junction photodiode 31 on another Ge substrate 1A are manufactured. Modulation array unit having a structure similar to that of the second embodiment in which modulation Fabry-Perot interferometers 10A comprising third and fourth (lower and upper) distributed Bragg reflectors 11A and 12A are integrated as an array. The demultiplexing array unit 40 is arranged on the light incident side of the modulation array unit 50.

Each demultiplexing fabric of the demultiplexing array section 40
In the Perot interferometer 10, the upper distributed Bragg reflector 1
2 has a membrane structure supported by a flexible arm with respect to the lower distributed Bragg reflector 11, and has a movable side on the upper distributed Bragg reflector 12 for attracting it to the substrate side by electrostatic force. A drive electrode 15 is manufactured, and a fixed-side drive electrode 14 is provided at a substrate position facing the drive electrode 15.
Has been produced. The fixed-side drive electrode 14 and the movable-side drive electrode 15 constitute an electrostatic actuator as a demultiplexing drive unit, and the fixed-side and movable-side drive electrodes 14,
By applying the wavelength-selecting control voltage E1 (DC voltage) to the gap 15, the upper distributed Bragg reflector 12 can be attracted toward the substrate by electrostatic force to adjust the air gap 13, and an arbitrary wavelength can be selected.

An anti-reflection coating film 41 for preventing reflection is formed on the back surface of the substrate 1 of the demultiplexing array section 40.

In each of the demultiplexing Fabry-Perot interferometers 10A of the modulation array section 50, the upper distributed Bragg reflector 12A has a membrane structure supported by a flexible arm with respect to the lower distributed Bragg reflector 11A. It is,
On the upper distributed Bragg reflector 12A, a movable-side driving electrode 15A for drawing it toward the substrate by electrostatic force
Is formed, and a fixed-side drive electrode 14A is formed at a position of the substrate opposed to this. Fixed side drive electrode 14
A and the movable-side drive electrode 15A constitute an electrostatic actuator as a drive means for modulation, and a modulation control voltage E2 applied between the fixed-side and movable-side drive electrodes 14A and 15A.
By applying the (modulation signal voltage), the upper distributed Bragg reflector 12A can be vibrated to execute light modulation.
However, when light detection is performed without performing modulation, a DC voltage for wavelength selection is used for E2.

The function of the device shown in FIG. 7 is briefly shown in the block diagram of FIG. In the case of receiving the light shown in FIG. 7A, the air gap 13 of the Fabry-Perot interferometer 10 of the stacked upper demultiplexing array unit 40 is controlled by applying the wavelength selection control voltage E1 (DC voltage). Then, the center wavelength λi of the transmitted optical signal is selected from the incident optical signals 44 (wavelengths λ _{1 to} λn). The modulation array unit 50
Integrated on photodiode 31 at
The Perot interferometer 10A also controls the air gap 13A with the control voltage E2 (DC voltage) so as to transmit light of the same wavelength λi. As a result, an electric signal 46 corresponding to the light intensity of the wavelength λi is obtained, and since the elements shown in FIG. 7 are arranged in an array, signals can be received in multi-channels as in the second embodiment.

In the case of transmitting the optical signal shown in FIG. 8B, this means that information is put back on the reflected optical signal 45, but
It works as follows. Stacked upper demultiplexing array unit 4
The zero Fabry-Perot interferometer 10 selects the center wavelength λi of the transmitted optical signal among the incident optical signals 44 (wavelengths λ _{1 to} λn) by controlling the air gap 13 by applying the wavelength selection control voltage E1. Then, a modulation control voltage E2 of an AC voltage corresponding to information to be transmitted is applied to the Fabry-Perot interferometer 10A integrated on the photodiode 31 in the modulation array unit 50, and the distributed Bragg reflector 12A on the upper side is applied. Vibrate. Thereby, the lower distributed Bragg reflector 11, the air gap 13, and the upper distributed Bragg reflector 1 functioning as a filter of the upper demultiplexing array unit 40.
The incident light signal 44 passing through 2 is modulated here and returns. For example, information can be given to the reflected light signal 45 by oscillating the Fabry-Perot interferometer 10A used as a modulator at about 5 MHz.

Therefore, when this structure is used on the communication terminal side, a signal can be put on the input light and reflected, so that the signal can be transmitted from the terminal side even if there is no expensive light source on the terminal side. There is an advantage.

In the present embodiment, the characteristics of the photodiode itself are not particularly taken into consideration, so that a simple PN junction photodiode is used as described above. Of course, in order to improve the response speed of the photodiode itself, the PIN photodiode is used. A diode may be formed and used.

According to the third embodiment, it is possible to function as a photodetector that selects and receives specific light, and further selects and reflects specific light, and reflects reflected light. It also functions as an optical modulator that can be modulated. Therefore, a multi-wavelength filter array in which a photodetector, a modulator, and a duplexer can be integrated in the same chip can be configured. In particular, since a signal can be put on the input light and reflected, there is an advantage that the signal can be sent from the terminal side even if there is no expensive light source on the terminal side.

In the third embodiment, the air gap of the demultiplexing array section 40 can be replaced with a fixed intermediate layer of a low-refractive index material having different thicknesses.

In the first and second embodiments, the case where the number of elements is eight is illustrated, and an example is shown in which the gap is adjusted to selectively transmit light of eight wavelengths. However, of course, the number of elements can be increased or decreased. Also in the third embodiment, the number of elements constituting the array can be appropriately increased or decreased.

In the distributed Bragg reflector of each embodiment, a SiN film is used as the high refractive index film and a SiN film is used as the low refractive index film.
Although the ON film has been exemplified, an SiO ₂ film may be used as the low refractive index film. Further, any other film configuration may be used as long as the material allows transmission of light to be demultiplexed.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0052]

As described above, according to the multi-wavelength filter array according to the present invention, Fabry-Perot interference using two distributed Bragg reflectors formed by micromachining and formed through an air gap as mirrors. By using the meter as a wavelength filter and forming an array of the filters, a duplexer having excellent wavelength resolution can be miniaturized. Also,
By integrating with a light receiving element, a light detecting function can also be provided. Further, by overlapping and using wavelength filters manufactured on different substrates, functions such as a duplexer, a modulator, and a photodetector can be integrated.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a first embodiment of a multi-wavelength filter array according to the present invention, showing a case where an optical demultiplexer is configured.

FIG. 2 is a perspective view of the first embodiment.

FIG. 3 is an enlarged cross-sectional view illustrating a configuration of a Fabry-Perot interferometer according to the first embodiment.

FIG. 4 is a graph showing the relationship between the number of layers of the Fabry-Perot interferometer and the wavelength resolution in the first embodiment.

FIG. 5 is a graph showing the relationship between the wavelength and the transmitted light intensity when the air gap of the Fabry-Perot interferometer according to the first embodiment is changed.

FIG. 6 is a front sectional view showing a configuration in which an optical demultiplexer and a photodetector are integrated according to a second embodiment of the present invention.

FIG. 7 is a third embodiment of the present invention, which is an optical demultiplexer;
FIG. 3 is a front sectional view showing a configuration in which a photodetector and a light modulator are integrated.

FIG. 8 is an explanatory diagram showing the operation of the third embodiment.

[Explanation of symbols]

 1, 1A substrate 3 lens system 4, 5 optical fiber 10, 10A Fabry-Perot interferometer 11, 11A, 12, 12A distributed Bragg reflector 13, 13A air gap 14, 14A fixed-side drive electrode 15, 15A movable-side drive Electrode for 20 Silicon nitride film 21 Silicon oxynitride film 31 Photodiode 40 Array part for demultiplexing 41 Anti-reflection coating film 50 Array part for modulation

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Osamu Shinoura 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation F-term (reference) 2H041 AA02 AA21 AB10 AB14 AB15 AB16 AB38 AC06 AZ03 AZ05 AZ08

Claims (6)

[Claims] 1. A plurality of Fabry-Perot interferometers comprising first and second distributed Bragg reflectors integrated on a substrate are arranged on the substrate, and the first and second distributed Bragg reflectors are arranged on the substrate. A multi-wavelength filter array, wherein the separation distances are variably controllable or set to different values. 2. A plurality of demultiplexing Fabry-Perot interferometers comprising first and second distributed Bragg reflectors integrated on a first substrate are arranged on the first substrate, wherein the first and second distributed Fabry-Perot interferometers are arranged on the first substrate. A demultiplexing array unit in which the distance separating the second distributed Bragg reflector is set to be variably controllable or different from each other; third and fourth distributed Bragg reflectors integrated on a second substrate Array comprising a plurality of modulator Fabry-Perot interferometers each of which is arranged on the second substrate, and a modulation driving means for oscillating the fourth distributed Bragg reflector with a modulation signal. A multi-wavelength filter array, characterized in that the branching array unit is arranged on the light incident side of the modulation array unit. 3. The multi-wavelength filter array according to claim 1, further comprising a demultiplexing drive unit that independently and variably controls a distance separating the first and second distributed Bragg reflectors. 4. The method according to claim 1, wherein the substrate is a germanium substrate, and the Fabry-Perot interferometer is integrated on a photodiode formed on the germanium substrate.
4. The multi-wavelength filter array according to 2 or 3. 5. The film thickness of each film constituting the distributed Bragg reflector is λ (1 + 2m) / 4n (where m: 1) with respect to the refractive index n of each film and the center wavelength λ of light to be selected. 0 or a natural number), and the distance separating the distributed Bragg reflectors forming the Fabry-Perot interferometer is λ / 2n ₀ (where n _{0 is} the refractive index of the medium separating the distributed Bragg reflectors). The multi-wavelength filter array according to claim 1, 2, 3, or 4. 6. The multi-layer reflector according to claim 1, wherein said distributed Bragg reflector comprises a high refractive index silicon nitride film and a low refractive index silicon oxide or silicon oxynitride film. Wavelength filter array.