CN121112881A - Interferometric measuring device, optical surface shape measurement method and optical measurement system - Google Patents

Interferometric measuring device, optical surface shape measurement method and optical measurement system

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Publication number
CN121112881A
CN121112881A CN202511374880.3A CN202511374880A CN121112881A CN 121112881 A CN121112881 A CN 121112881A CN 202511374880 A CN202511374880 A CN 202511374880A CN 121112881 A CN121112881 A CN 121112881A
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CN
China
Prior art keywords
light
mirror
optical fiber
fiber coupler
path
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202511374880.3A
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Chinese (zh)
Inventor
张文喜
焦琪璐
朱聪慧
伍洲
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Aerospace Information Research Institute of CAS
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Aerospace Information Research Institute of CAS
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Application filed by Aerospace Information Research Institute of CAS filed Critical Aerospace Information Research Institute of CAS
Priority to CN202511374880.3A priority Critical patent/CN121112881A/en
Publication of CN121112881A publication Critical patent/CN121112881A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02015—Interferometers characterised by the beam path configuration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

The invention provides an interferometry device, an optical surface shape measurement method and an optical measurement system, which can be applied to the technical field of optical precision measurement. The device comprises a light source module (1) used for generating measuring light and reference light, a double-core optical fiber coupler (4) comprising an outgoing end face and a reflecting face, the double-core optical fiber coupler (4) used for outgoing the measuring light from the outgoing end face to a standard mirror (5) and reflecting the measuring light returned by the standard mirror (5) from the reflecting face to an imaging mirror (7) and outgoing the reference light from the outgoing end face to the imaging mirror (7), the standard mirror (5) arranged in an outgoing light path of the measuring light output by the double-core optical fiber coupler (4), the imaging mirror (7) arranged in an outgoing light path of the reference light output by the double-core optical fiber coupler (4) and in a reflecting light path of the reflecting face, and a detector (8) used for receiving the measuring light output by the imaging mirror (7) and the reference light and generating interference signals based on the measuring light and the reference light.

Description

Interferometry device, optical surface shape measurement method, and optical measurement system
Technical Field
The present invention relates to the field of optical precision measurement technologies, and in particular, to an interferometry device, an optical surface shape measurement method, and an optical measurement system.
Background
The full-view heterodyne phase shifting technology is widely applied to the interferometry fields of surface shapes, transmitted wave fronts and the like, mainly adopts a short coherence technology when applied to a Fizeau interferometer, has complex optical path matching operation, is applied to the effects of parasitic waves and component shunt crosstalk, which are reflected by parallel light paths through front and rear surfaces of a flat plate, of a Tasman-Green and Mach-Zehnder structure, and has the effects of reference surface shapes on measurement results.
Disclosure of Invention
In view of the above problems, the present invention provides an interferometry device, an optical surface shape measurement method, and an optical measurement system for solving the technical problem that a reference surface shape affects a measurement result.
According to a first aspect of the present invention, there is provided a light source module 1 for generating two light beams having a predetermined frequency difference, the two light beams including measurement light and reference light;
A twin-core optical fiber coupler 4 including an exit end face and a reflecting face, the twin-core optical fiber coupler 4 being configured to exit the measurement light from the exit end face to a standard mirror 5, and reflect the measurement light returned by the standard mirror 5 from the reflecting face to an imaging mirror 7, and to exit the reference light from the exit end face to the imaging mirror 7;
The standard mirror 5 is arranged in an outgoing light path of the measuring light output by the double-core optical fiber coupler 4;
The imaging mirror 7 is arranged in an outgoing light path of the reference light output by the double-core optical fiber coupler 4 and in a reflection light path of the reflection surface;
And a detector 8 for receiving the measurement light and the reference light output from the imaging mirror 7 and generating an interference signal based on the measurement light and the reference light.
Optionally, the apparatus further includes:
a first optical waveguide 2 for transmitting a path of light beam from the light source module 1 as the measurement light;
A second optical waveguide 3 for transmitting another light beam from the light source module 1 as the reference light.
Optionally, the light source module 1 includes:
a laser 100 for generating laser light;
the polarization maintaining optical fiber 110 comprises an input end and two output ends, wherein the input end is connected with the laser 100, and the polarization maintaining optical fiber 110 is used for dividing the laser into a first path of light beam and a second path of light beam;
A cascade acousto-optic frequency shifter 120, connected to the first output end of the polarization maintaining optical fiber 110, for shifting the frequency of the first path of light beam to generate the measurement light;
an electrically adjustable optical fiber attenuator 130 is connected to the second output end of the polarization maintaining optical fiber 110, and is used for adjusting the light intensity of the second path of light beam to generate the reference light.
Optionally, the exit end face of the dual-core optical fiber coupler 4 is located at the incident point of the standard optical element 5.
Optionally, the reflecting surface position of the dual-core fiber coupler 4 and/or the exit point position of the reference light are located at the focal point of the imaging mirror 7.
Optionally, the apparatus further includes:
And the mirror to be measured 6 is arranged in an emergent light path of the standard mirror 5 and is used for reflecting the measuring light emergent from the standard mirror 5 so as to enable the measuring light to return along the emergent light path.
Optionally, the first optical waveguide 2 and the second optical waveguide 3 are two independent single-mode polarization maintaining optical fibers respectively;
The first optical waveguide (2) and the second optical waveguide (3) are arranged in the same structure.
A second aspect of the invention provides a method of optical profile measurement using an interferometry apparatus according to the first aspect, the method comprising:
Generating, by the light source module 1, two light beams having a predetermined frequency difference, the two light beams including measurement light and reference light;
Introducing the measuring light and the reference light into a dual-core optical fiber coupler 4;
the measuring light is emitted to a standard mirror 5 through the double-core optical fiber coupler 4, is processed by the standard mirror 5 and then is guided to a region to be measured, measuring light returned from the region to be measured is received, and then the measuring light is reflected to an imaging mirror 7 through a reflecting surface of the double-core optical fiber coupler 4;
The reference light is emitted to the imaging mirror 7 through the two-core optical fiber coupler 4;
processing the returned measuring light and reference light by the imaging mirror 7 and guiding the processed measuring light and reference light to a detector 8;
The measurement light is interfered with a reference light by the detector 8 to generate an interference signal.
Optionally, the method includes:
Demodulating the interference signal to obtain the phase change information of the region to be detected.
The reference beam is processed by the reference light path module to generate and output a first indicating beam and a second indicating beam;
A third aspect of the present invention provides an optical system comprising:
An interferometry apparatus according to the first aspect, and
The to-be-detected piece 6 is arranged in the emergent light path of the standard mirror 5;
wherein the interferometry device is used for performing non-contact measurement on the surface shape, displacement or optical characteristics of the to-be-measured member 6.
Drawings
The foregoing and other objects, features and advantages of the invention will be apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:
FIG. 1 schematically illustrates a block diagram of an interferometric device according to an embodiment of the invention;
fig. 2 schematically illustrates a block diagram of a light source module according to an embodiment of the present invention;
FIG. 3 schematically illustrates a block diagram of an interferometric device for planar surface shape measurement in accordance with an embodiment of the present invention;
FIG. 4 schematically illustrates a block diagram of an interferometric device for transmitting a wavefront through an element, in accordance with an embodiment of the present invention;
fig. 5 schematically shows a flow chart of a beam alignment method according to an embodiment of the invention.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be understood that the description is only illustrative and is not intended to limit the scope of the invention. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.
All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.
Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a convention should be interpreted in accordance with the meaning of one of skill in the art having generally understood the convention (e.g., "a system having at least one of A, B and C" would include, but not be limited to, systems having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). Where a formulation similar to at least one of "A, B or C, etc." is used, in general such a formulation should be interpreted in accordance with the ordinary understanding of one skilled in the art (e.g. "a system with at least one of A, B or C" would include but not be limited to systems with a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). It should also be appreciated by those skilled in the art that virtually any disjunctive word and/or phrase presenting two or more alternative items, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the items, either of the items, or both. For example, the phrase "a or B" should be understood to include the possibility of "a" or "B", or "a and B".
FIG. 1 schematically illustrates a block diagram of an interferometric measuring device according to an embodiment of the invention.
As shown in fig. 1, the interferometry apparatus includes a light source module 1, a two-core optical fiber coupler 4, a standard mirror 5, an imaging mirror 7, and a detector 8.
The light source module 1 is used for generating two light beams with a preset frequency difference, wherein the two light beams comprise measuring light and reference light. The twin-core optical fiber coupler 4 includes an exit end face and a reflecting face, and the twin-core optical fiber coupler 4 is configured to exit the measurement light from the exit end face to the standard mirror 5, and reflect the measurement light returned by the standard mirror 5 from the reflecting face to the imaging mirror 7, and to exit the reference light from the exit end face to the imaging mirror 7. And a standard mirror 5 arranged in the outgoing light path of the measuring light output by the double-core optical fiber coupler 4. The imaging mirror 7 is disposed in the outgoing light path of the reference light output from the twin-core optical fiber coupler 4 and in the reflection light path of the reflection surface. And a detector 8 for receiving the measurement light and the reference light output from the imaging mirror 7 and generating an interference signal based on the measurement light and the reference light.
According to the embodiment of the invention, through the optical path design of the dual-core optical fiber coupler and the standard mirror, the system can guide the returned measuring light by utilizing the reflecting surface, the multi-pose measurement (such as rotation or translation) of the piece to be measured or the system is realized, the corresponding absolute measurement algorithm (such as a shift average method) is adopted, the real surface shape error of the surface to be measured is accurately separated from the mixed result containing the transmission wavefront error of the system, and the end face of the optical fiber 4 directly emits high-quality reference light. Therefore, the fundamental limitation that the reference surface shape error is directly transmitted to the measurement result in the traditional interferometry is fundamentally overcome, and the accuracy and the reliability of the measurement are obviously improved.
In some embodiments of the invention, the exit end face of the dual-core fiber coupler 4 is located at the point of incidence of the standard optical element 5.
In some embodiments of the invention, the reflecting surface position of the twin-core fiber coupler 4 and/or the exit point position of the reference light is located at the focal point of the imaging mirror 7.
In some embodiments of the present invention, the interferometry device further includes a mirror to be measured 6 disposed in an outgoing light path of the standard mirror 5, and configured to reflect the measurement light outgoing from the standard mirror 5, so that the measurement light returns along the outgoing light path.
In some embodiments of the invention, as shown in FIG. 1, the interferometry apparatus further comprises a first optical waveguide 2 and a second optical waveguide 3. The first optical waveguide 2 is for transmitting one path of light beam from the light source module 1 as measurement light. The second optical waveguide 3 is for transmitting another light beam from the light source module 1 as reference light.
Wherein the first optical waveguide 2 and the second optical waveguide 3 are two independent single-mode polarization maintaining optical fibers respectively. The first optical waveguide 2 and the second optical waveguide 3 may be disposed within the same structure such that the environments experienced by the reference light and the measurement light are highly uniform, and for example, the environments may be vibration, temperature change, stress, and the like.
According to the embodiment of the present invention, on the one hand, the reference light and the measurement light are transmitted in two side-by-side cores (the first optical waveguide 2 and the second optical waveguide 3) of the same structure after exiting from the light source module until exiting from the exit end face of the two-core optical fiber. The environments experienced by the reference light and the measurement light are highly consistent. After the reference light is emitted, the reference light directly goes to the imaging lens, and the measuring light is reflected by the standard lens and the to-be-measured piece and then goes to the same imaging lens, so that non-common-path errors can be greatly restrained, and the immunity to environmental disturbance is extremely strong. On the other hand, the spectroscopic function is internally performed by the optical fiber coupler. The problem of parasitic interference caused by the reflection of the front and rear surfaces of the flat spectroscope is thoroughly eliminated from the physical structure. In addition, the measuring light path adopts a divergent light path form directly emitted from the end face of the optical fiber, and compared with a parallel light path, the measuring light path has lower sensitivity to residual parasitic reflection light generated on the optical surface in the system, and the influence of parasitic interference on a measuring result is further weakened.
In some embodiments of the present invention, the light source module may be any heterodyne interference light source such as a narrow linewidth dual-frequency heterodyne light source or a short coherence dual-frequency heterodyne light source. The short coherent light source can eliminate the influence of other light beams on the measurement result, and the narrow linewidth light source can improve the coherence length, so that the device is suitable for the measurement of a measured piece with a large optical path range and a long-focus large-caliber element.
In some embodiments of the present invention, the phase shift mode is heterodyne phase shift, mechanical phase shift, wavelength phase shift or polarization phase shift, and the heterodyne phase shift may also be electro-optic phase shift or frequency shift.
In some embodiments, the phase resolving method may be a heterodyne demodulation method or an N-step phase shifting method, among other various phase resolving methods.
In some embodiments, heterodyne phase shifting may be achieved by an acousto-optic frequency shifter or an electro-optic frequency shifter.
In some embodiments, the signal relationship on the detector 8 of two beams (a first index beam and another measuring beam, a second index beam and a measuring beam) having a predetermined relative phase relationship is expressed as:
wherein, the For the intensity of the background light,In order to modulate the intensity of the light,For the difference frequency to be the frequency of the difference,For the moment of sampling,Is the image plane of the mirror 6 to be measuredPhase information introduced by the profile at the location.
Setting the sampling frame frequency and the difference frequency of the detector 8 to match to finish the acquisition of the N+1 step-shifted measurement image, wherein the following formula is shown:
Wherein N is the number of phase-shifting steps, For the i-th step of the interference intensity acquired by the detector 8,The sampling instants corresponding to the i-th phase shift are provided for the detector 8.
The calculated phase is shown in the following formula:
fig. 2 schematically illustrates a structure diagram of a light source module according to an embodiment of the present invention.
As shown in fig. 2, the light source module 1 includes a laser 100 for generating laser light, a polarization maintaining optical fiber 110 including an input end and two output ends, the input end connected to the laser 100, the polarization maintaining optical fiber 110 for dividing the laser light into a first path of light beam and a second path of light beam, a cascade acousto-optic frequency shifter 120 connected to the first output end of the polarization maintaining optical fiber 110 for shifting the frequency of the first path of light beam to generate a measuring light beam, and an electrically adjustable optical fiber attenuator 130 connected to the second output end of the polarization maintaining optical fiber 110 for adjusting the light intensity of the second path of light beam to generate a reference light beam.
The laser 100 emits a narrow linewidth light beam, the light beam is divided into two paths through the polarization maintaining one-to-two optical fibers 110, one path of the light beam passes through the cascade acousto-optic frequency shifter 120, the cascade acousto-optic frequency shifter 120 is packaged by the cascade acousto-optic frequency shifters, difference frequency light is generated after frequency shifting, the frequency is between a few Hz and a few hundred Hz, and the light beam after frequency shifting is coupled into the single-mode polarization maintaining optical fiber 4 to form measuring light. The other path of the light passes through the optical fiber electric adjustable attenuation sheet 130, the light intensity of the light can be adjusted through an electric signal to be matched with the other path of the light, the contrast of interference fringes is ensured, and the emergent light of the optical fiber electric adjustable attenuation sheet 130 is coupled into the first output end 2 and the second output end 3 to form reference light.
According to the embodiment of the invention, the narrow linewidth double-frequency heterodyne light source 1 generates two paths of light beams, one of the light beams is optically coupled into the first optical waveguide 2 as measurement light, and the measurement light is emitted to the standard mirror 5 through the double-core optical fiber coupler 4, wherein the emergent end face of the double-core optical fiber coupler 4 is positioned at the designed incident point 5 of the standard mirror 5, so that the effective F number of the standard mirror is ensured. The standard mirror emits high-quality spherical waves, the spherical waves reach the mirror 6 to be detected, the spherical waves return to the standard mirror 5 in an original path through the mirror 6 to be detected, reach the double-core optical fiber coupler 4, reflect through the double-core optical fiber coupler 4, reach the imaging mirror 7, reach the detector 8 through collimation of the imaging mirror 7, and the reflection point of the double-core optical fiber emitting head is located at the focal point of the imaging mirror 7, so that the measuring light reaching the detector 8 is collimated light.
According to the embodiment of the invention, the other beam generated by the light source module 1 is optically coupled into the second optical waveguide 3 as the reference light, and is emitted through the dual-core optical fiber coupler 4 to directly reach the imaging mirror 7, and the emitting end of the dual-core optical fiber coupler 4 is positioned at the focal position of the imaging mirror 7, so that the reference light reaching the detector 8 is collimated light.
It will be appreciated that the measurement light interferes with the reference light at the detector 8 to calibrate the base surface shape of the standard mirror 5 and the imaging mirror 7, and has great applicability in absolute measurement.
In some embodiments, the standard mirror 6 is replaced and the planar element and the element transmitted wavefront can be measured, as shown in figures 3 and 4 below, where the element 9 can be a standard flat crystal or planar mirror.
Fig. 5 schematically shows a flow chart of an optical profile measurement method according to an embodiment of the invention.
As shown in fig. 5, the method includes operations S510-S550. The method may be implemented using the interferometry apparatus shown in FIG. 1.
In operation S510, two light beams having a predetermined frequency difference, including measurement light and reference light, are generated by the light source module 1.
In operation S520, the measurement light and the reference light are introduced into the dual-core optical fiber coupler 4.
In operation S530, the measurement light is emitted to a standard mirror 5 through the dual-core fiber coupler 4, is processed by the standard mirror 5, and is directed to a region to be measured, and the measurement light returned from the region to be measured is received, and is reflected to an imaging mirror 7 by the reflecting surface of the dual-core fiber coupler 4.
In operation S540, the reference light is emitted to the imaging mirror 7 through the two-core optical fiber coupler 4.
In operation S550, the returned measuring light and reference light are processed by the imaging mirror 7 and directed to a detector 8.
In operation S560, the measurement light is interfered with the reference light at the detector 8 to generate an interference signal.
In some embodiments, the interference signal may be demodulated to obtain phase change information of the area under test.
The embodiment of the invention also provides an optical measurement system, which comprises the interferometry device shown in figure 1 and at least one piece to be measured. The measuring beam generated by the interferometry device is guided to the piece to be measured, and returns to the interferometry device to perform interferometry, so as to perform non-contact measurement on the surface shape, displacement or optical characteristic of the piece to be measured 6.
Any number of modules, units, or at least some of the functionality of any number of the modules, units, or units may be implemented in one module in accordance with embodiments of the invention. Any one or more of the modules, units according to embodiments of the invention may be implemented as a split into multiple modules. Any one or more of the modules, units, or units according to embodiments of the invention may be implemented at least in part as a hardware circuit, such as a Field Programmable Gate Array (FPGA), a Programmable Logic Array (PLA), a system on a chip, a system on a substrate, a system on a package, an Application Specific Integrated Circuit (ASIC), or in any other reasonable manner of hardware or firmware that integrates or packages the circuit, or in any one of or in any suitable combination of three of software, hardware, and firmware. Or one or more of the modules, units according to embodiments of the invention may be at least partly implemented as computer program modules which, when run, may perform the corresponding functions.
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams or flowchart illustration, and combinations of blocks in the block diagrams or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
Those skilled in the art will appreciate that the features recited in the various embodiments of the invention and/or in the claims may be combined in various combinations and/or combinations, even if such combinations or combinations are not explicitly recited in the invention. In particular, the features recited in the various embodiments of the invention and/or in the claims can be combined in various combinations and/or combinations without departing from the spirit and teachings of the invention. All such combinations and/or combinations fall within the scope of the invention.
While the present invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents. The scope of the invention should, therefore, be determined not with reference to the above-described embodiments, but instead should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims (10)

1. An interferometry device, the device comprising:
a light source module (1) for generating two light beams having a predetermined frequency difference, the two light beams including measurement light and reference light;
-a dual-core fiber coupler (4) comprising an exit end face and a reflecting face, the dual-core fiber coupler (4) being adapted to exit the measurement light from the exit end face to a standard mirror (5) and reflect the measurement light returned by the standard mirror (5) from the reflecting face to an imaging mirror (7), and to exit the reference light from the exit end face to the imaging mirror (7);
the standard mirror (5) is arranged in an emergent light path of the measuring light output by the double-core optical fiber coupler (4);
The imaging mirror (7) is arranged in an emergent light path of the reference light output by the double-core optical fiber coupler (4) and in a reflection light path of the reflection surface;
and a detector (8) for receiving the measurement light and the reference light output from the imaging mirror (7) and generating an interference signal based on the measurement light and the reference light.
2. The interferometry device of claim 1, wherein the device further comprises:
a first optical waveguide (2) for transmitting a beam of light from the light source module (1) as the measurement light;
And a second optical waveguide (3) for transmitting another light beam from the light source module (1) as the reference light.
3. Interferometry device according to claim 1, wherein the light source module (1) comprises:
a laser (100) for generating laser light;
The polarization maintaining one-to-two optical fiber (110) comprises an input end and two output ends, wherein the input end is connected with the laser (100), and the polarization maintaining one-to-two optical fiber (110) is used for dividing the laser into a first path of light beam and a second path of light beam;
the cascade acousto-optic frequency shifter (120) is connected with the first output end of the polarization maintaining one-to-two optical fiber (110) and is used for shifting the frequency of the first path of light beam to generate the measuring light;
And the electrically adjustable optical fiber attenuation sheet (130) is connected with the second output end of the polarization maintaining optical fiber (110) and is used for adjusting the light intensity of the second path of light beam so as to generate the reference light.
4. Interferometry device according to claim 1, characterized in that the exit end face of the dual-core fiber coupler (4) is located at the point of incidence of the standard optical element (5).
5. Interferometry device according to claim 1, characterized in that the reflecting surface position of the dual-core fiber coupler (4) and/or the exit point position of the reference light is located at the focal point of the imaging mirror (7).
6. The interferometry device of claim 1, wherein the device further comprises:
And the mirror to be measured (6) is arranged in an emergent light path of the standard mirror (5) and is used for reflecting the measuring light emergent from the standard mirror (5) so as to enable the measuring light to return along the emergent light path.
7. Interferometry apparatus according to claim 1, wherein the first optical waveguide (2) and the second optical waveguide (3) are two independent single-mode polarization maintaining fibers, respectively;
The first optical waveguide (2) and the second optical waveguide (3) are arranged in the same structure.
8. An optical profile measuring method, implemented using the interferometry device according to any of claims 1-7, comprising:
Generating, by a light source module (1), two light beams having a predetermined frequency difference, the two light beams including measurement light and reference light;
Introducing the measuring light and reference light into a dual-core optical fiber coupler (4);
The measuring light is emitted to a standard mirror (5) through the double-core optical fiber coupler (4), is processed by the standard mirror (5) and then is guided to a region to be measured, measuring light returned from the region to be measured is received, and then the measuring light is reflected to an imaging mirror (7) through a reflecting surface of the double-core optical fiber coupler (4);
-emitting the reference light to the imaging mirror (7) through the twin-core fiber coupler (4);
Processing the returned measuring light and reference light with the imaging mirror (7) and guiding to a detector (8);
the measuring light is interfered with a reference light on the detector (8) to generate an interference signal.
9. The optical profile measurement method according to claim 8, characterized in that the method comprises:
Demodulating the interference signal to obtain the phase change information of the region to be detected.
10. An optical measurement system, comprising:
an interferometry device according to any of claims 1-7, and
The piece to be detected (6) is arranged in the emergent light path of the standard mirror (5);
The interferometry device is used for carrying out non-contact measurement on the surface shape, displacement or optical characteristics of the to-be-measured piece (6).
CN202511374880.3A 2025-09-25 2025-09-25 Interferometric measuring device, optical surface shape measurement method and optical measurement system Pending CN121112881A (en)

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