Laser Synthesis Wavelength Measurement Interferometer Based on Fiber Coupling Optimization

Abstract

This invention provides a laser synthesis wavelength measurement interferometer based on optimized fiber coupling. The interferometer includes: a composite laser source, a fiber coupler assembly, a fiber beam splitter assembly, a polarization beam splitter assembly, an adjustable optical path reference fiber, an adjustable optical path measurement fiber, a photodetector assembly, and an electronic control system, all interconnected. The composite laser source emits two laser beams with wavelengths λ1 and λ2 respectively. The fiber coupler assembly includes a first fiber coupler, a second fiber coupler, and a third fiber coupler. The fiber beam splitter assembly includes a first fiber beam splitter and a second fiber beam splitter. The polarization beam splitter assembly includes a first polarization beam splitter and a second polarization beam splitter. The photodetector assembly includes a first photodetector, a second photodetector, and a third photodetector. This invention improves the measurement accuracy of the interferometer, and damaged parts of the interferometer can be replaced individually, facilitating maintenance by repair personnel.

Description

Technical Field

[0001] This utility model relates to the technical field of wavelength measurement, and more specifically, to a laser synthesis wavelength measurement interferometer based on fiber coupling optimization. Background Technology

[0002] The Michelson laser interferometer is a high-precision measuring device designed based on the wave nature of light and the principle of interference.

[0003] The core technology utilizes a physical process of "spectral dispersion-propagation-recombination-interference" to transform minute displacements or changes in physical quantities that are difficult to observe directly into visible changes in light intensity, exhibiting a "through-and-through" pattern, thereby achieving nanometer-level precision measurements. Throughout the measurement process, such as... Figure 2 As shown, a laser source first emits a highly monochromatic beam with excellent coherence; helium-neon lasers are commonly used today. When this beam is incident on a beam splitter, which is an optical mirror coated with a semi-transparent, semi-reflective film, it is precisely split into two beams of approximately equal energy, following Fresnel's laws of reflection and transmission. One beam is called the transmitted beam, and the other is called the reflected beam. The transmitted beam passes through the beam splitter into the measuring arm, is reflected by a movable mirror at the end, and returns along the same path. The reflected beam is reflected by the surface of the beam splitter to the fixed arm, and is reflected by a fixed-position plane mirror, also returning. This entire process not only achieves the distribution of light energy but also creates the conditions for subsequent interference through path separation.

[0004] When two beams of light propagate along separate paths, the external physical quantity to be measured will directly or indirectly affect the reflector of the measuring arm, causing a change in its optical path length d. After the two beams of light return to the beam splitter and rejoin, the round-trip path of the light is 2d, and the optical path difference carries all the information of the physical quantity to be measured.

[0005] The two beams of light, after merging, produce a phase difference due to the optical path difference, and interfere according to the principle of superposition of light. When the two beams interfere constructively, the two peaks superimpose, resulting in maximum light intensity and displaying bright fringes. When the two beams interfere destructively, the peaks and troughs cancel each other out, and the light intensity approaches zero, displaying dark fringes. Bright and dark fringes are arranged in alternating circular patterns from the inside out on the display screen, which is typically made of a single piece of frosted glass. The interference result appears on the display screen as alternating bright and dark interference fringes, and their spatial distribution and variation are directly related to the variation pattern of the optical path difference. When the length of the measuring arm d changes, the optical path difference changes by N wavelengths corresponding to the number of interference fringe shifts. Therefore, the change in optical path length satisfies:

[0006] (1)

[0007] In equation (1), The wavelength of the laser emitted by the laser source;

[0008] Therefore, the relationship between the movement d of the measuring arm and the number N of the "through" and "through" stripes can be further solved as follows:

[0009] (2)

[0010] The above methods can basically achieve large-scale displacement measurements at the millimeter level, but due to the need for finer subdivision of interference fringes...

[0011] The sinusoidal error and the first-order nonlinear error caused by polarization state errors such as non-orthogonality of polarized light, ellipticization, and polarization leakage greatly limit further improvements in measurement accuracy.

[0012] Therefore, based on the principles provided by the Michelson laser interferometer, we developed a laser-synthesized wavelength nanometer interferometer to correct the shortcomings of the Michelson laser interferometer. Utility Model Content

[0013] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0014] Therefore, the purpose of this invention is to propose a laser synthesis wavelength measurement interferometer based on fiber coupling optimization.

[0015] To achieve the above objectives, the present invention provides a laser synthesis wavelength measurement interferometer based on fiber coupling optimization. The interferometer includes: a composite laser source, a fiber coupler assembly, a fiber beam splitter assembly, a polarization beam splitter assembly, an adjustable optical path reference fiber, an adjustable optical path measurement fiber, a photodetector assembly, and an electronic control system, all interconnected. The composite laser source emits two beams with wavelengths of... The laser;

[0016] The fiber optic coupler assembly includes: a first fiber optic coupler, a second fiber optic coupler, and a third fiber optic coupler; the fiber optic beam splitter assembly includes: a first fiber optic beam splitter and a second fiber optic beam splitter; the polarization beam splitter assembly includes: a first polarization beam splitter and a second polarization beam splitter; the photodetector assembly includes: a first photodetector, a second photodetector, and a third photodetector.

[0017] Wherein, the output end of the composite laser source is connected to the input end of the first fiber coupler; the output end of the first fiber coupler is connected to the input end of the first fiber beam splitter; the first output end of the first fiber beam splitter is connected to the input end of the adjustable optical path reference fiber; and the second output end of the first fiber beam splitter is connected to the input end of the first polarization beam splitter.

[0018] The output end of the adjustable optical path reference fiber is connected to the first input end of the third fiber coupler; the first output end of the first polarization beam splitter is connected to the first input end of the second fiber coupler; the second output end of the first polarization beam splitter is connected to the input end of the adjustable optical path measurement fiber; and the output end of the adjustable optical path measurement fiber is connected to the second input end of the second fiber coupler.

[0019] The output of the second fiber coupler is connected to the second input of the third fiber coupler; the output of the third fiber coupler is connected to the input of the second polarization beam splitter; the first output of the second polarization beam splitter is connected to the input of the first photodetector; the second output of the second polarization beam splitter is connected to the input of the second fiber beam splitter; the first output of the second fiber beam splitter is connected to the input of the second photodetector; the second output of the second fiber beam splitter is connected to the input of the third photodetector; the first photodetector, the second photodetector, and the third photodetector are electrically connected to the electronic control system.

[0020] The beneficial effects of this utility model are:

[0021] The laser synthesis wavelength measurement interferometer based on fiber coupling optimization of this invention has the following technical advantages:

[0022] (1) The measurement accuracy of this interferometer is improved due to the enclosed environment of the optical fiber;

[0023] (2) Since each fiber optic segment is replaceable, the damaged part of the interferometer can be replaced individually, which facilitates maintenance operations for maintenance personnel;

[0024] (3) The combination of photoelectric and optical technologies makes the measurement method of the interferometer more convenient and the measurement results more reliable.

[0025] (4) The interferometer is not expensive to manufacture and has a very promising market promotion value.

[0026] Additional aspects and advantages of this invention will become apparent from the description which follows, or may be learned by practice of this invention. Attached Figure Description

[0027] Figure 1 A schematic block diagram of a laser synthesis wavelength measurement interferometer based on fiber coupling optimization according to an embodiment of the present invention is shown.

[0028] Figure 2A schematic diagram of a Michelson laser interferometer according to an embodiment of the present invention is shown;

[0029] Among them, 1 is a laser synthesis wavelength measurement interferometer based on fiber coupling optimization, 11 is a composite laser source, 12 is a fiber coupler assembly (not shown in the figure), 13 is a fiber beam splitter assembly (not shown in the figure), 14 is a polarization beam splitter assembly (not shown in the figure), 15 is a reference fiber with adjustable optical path, 16 is a measurement fiber with adjustable optical path, 17 is a photodetector assembly (not shown in the figure), 18 is an electronic control system, 121 is a first fiber coupler, 122 is a second fiber coupler, 123 is a third fiber coupler, 131 is a first fiber beam splitter, 132 is a second fiber beam splitter, 141 is a first polarization beam splitter, 142 is a second polarization beam splitter, 171 is a first photodetector, 172 is a second photodetector, and 173 is a third photodetector. Detailed Implementation

[0030] In order to better understand the above-mentioned objectives, features and advantages of this utility model, such as Figure 1 and Figure 2 As shown in the accompanying drawings and specific embodiments, the present invention will be further described in detail below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0032] Figure 1 A schematic block diagram of a laser synthesis wavelength measurement interferometer based on fiber coupling optimization according to an embodiment of the present invention is shown. Figure 1 As shown, the laser synthesis wavelength measurement interferometer 1 based on fiber coupling optimization includes: a composite laser source 11, a fiber coupler assembly 12 (not shown), a fiber beam splitter assembly 13 (not shown), a polarization beam splitter assembly 14 (not shown), a reference fiber 15 with adjustable optical path, a measurement fiber 16 with adjustable optical path, a photodetector assembly 17 (not shown), and an electronic control system 18, all interconnected. The composite laser source emits two beams with wavelengths of... The laser;

[0033] The fiber optic coupler assembly 12 includes a first fiber optic coupler 121, a second fiber optic coupler 122, and a third fiber optic coupler 123; the fiber optic beam splitter assembly 13 includes a first fiber optic beam splitter 131 and a second fiber optic beam splitter 132; the polarization beam splitter assembly 14 includes a first polarization beam splitter 141 and a second polarization beam splitter 142; the photodetector assembly 17 includes a first photodetector 171, a second photodetector 172, and a third photodetector 173.

[0034] The output end of the composite laser source 11 is connected to the input end of the first fiber coupler 121; the output end of the first fiber coupler 121 is connected to the input end of the first fiber beam splitter 131; the first output end of the first fiber beam splitter 131 is connected to the input end of the adjustable optical path reference fiber 15; and the second output end of the first fiber beam splitter 131 is connected to the input end of the first polarization beam splitter 141.

[0035] The output end of the adjustable optical path reference fiber 15 is connected to the first input end of the third fiber coupler 123; the first output end of the first polarization beam splitter 141 is connected to the first input end of the second fiber coupler 122; the second output end of the first polarization beam splitter 141 is connected to the input end of the adjustable optical path measurement fiber 16; the output end of the adjustable optical path measurement fiber 16 is connected to the second input end of the second fiber coupler 122.

[0036] The output of the second fiber coupler 122 is connected to the second input of the third fiber coupler 123; the output of the third fiber coupler 123 is connected to the input of the second polarization beam splitter 142; the first output of the second polarization beam splitter 142 is connected to the input of the first photodetector 171; the second output of the second polarization beam splitter 142 is connected to the input of the second fiber beam splitter 132; the first output of the second fiber beam splitter 132 is connected to the input of the second photodetector 172; the second output of the second fiber beam splitter 132 is connected to the input of the third photodetector 173; the first photodetector 171, the second photodetector 172, and the third photodetector 173 are respectively electrically connected to the electronic control system 18.

[0037] The composite laser source 11 is used to emit two beams with wavelengths of respectively. The laser;

[0038] The first fiber coupler 121 is used to receive the two beams with wavelengths of respectively The laser, and the two beams with wavelengths respectively The lasers are coupled together to emit the coupled laser. ;

[0039] The first fiber beam splitter 131 is used to receive the coupled laser beam. and the coupled laser The laser beams are divided into two groups of equal intensity: a first group and a second group. Both groups contain two wavelengths. The laser;

[0040] The first fiber beam splitter 131 is also used to transmit the first group of lasers and the second group of lasers to the adjustable optical path reference fiber 15 and the first polarization beam splitter 141, respectively.

[0041] The adjustable optical fiber 15 is used to receive the first group of lasers and adjust the optical path of the first group of lasers.

[0042] The adjustable optical path reference fiber 15 is also used to transmit the first set of lasers after the optical path is adjusted as a reference arm to the third fiber coupler 123.

[0043] The first polarization beam splitter 141 is used to receive the second group of laser beams and split the second group of laser beams into two beams with wavelengths of respectively. The laser;

[0044] The first polarization beam splitter 141 is also used to split the wavelength of the first beam into... The laser is emitted to the second fiber coupler 122, and the wavelength of the first split is... The laser is emitted into the adjustable optical path measuring fiber 16;

[0045] The adjustable optical path measuring fiber 16 is used to receive the wavelength divided in the first step. The laser, and the wavelength of the first segment is... The laser's optical path is adjusted;

[0046] The adjustable optical path measuring fiber 16 is also used to transmit the wavelength after the optical path is adjusted to... The laser is emitted as a measuring arm to the second fiber coupler 122;

[0047] The second fiber coupler 122 is also used to receive wavelengths of The measuring arm and the first wavelength segmented are The laser, and the wavelength is The measuring arm and the first wavelength segmented are The lasers are coupled together to emit the coupled laser. ;

[0048] The third fiber coupler 123 is used to receive the reference arm and the coupled laser. and the reference arm and the coupled laser They are coupled together to emit the coupled laser. ;

[0049] The second polarization beam splitter 142 is used to receive the coupled laser beam. and the coupled laser The second split into two beams with wavelengths of... The laser;

[0050] The second polarization beam splitter 142 is also used to split the second wavelength into... The laser light is emitted to the first photodetector 171, and the second wavelength is divided into... The laser is emitted to the second fiber beam splitter 132;

[0051] The second fiber optic beam splitter 132 is used to receive the second split wavelength. The laser, and the second division into wavelengths of The laser beam is divided into two groups: a third group and a fourth group, both with equal intensity; the third and fourth groups of laser beams are of wavelength... The laser;

[0052] The second fiber beam splitter 132 is also used to transmit the third group of lasers and the fourth group of lasers to the second photodetector 172 and the third photodetector 173, respectively;

[0053] The first photodetector 171 is used to receive the wavelength divided in the second step. The system receives the laser signal, converts the received laser signal into a corresponding electrical signal, and then sends the corresponding electrical signal to the electronic control system.

[0054] The second photodetector 172 is used to receive the third group of lasers, convert the received laser signals into corresponding electrical signals, and then send the corresponding electrical signals to the electronic control system;

[0055] The third photodetector 173 is used to receive the fourth group of lasers, convert the received laser signals into corresponding electrical signals, and then send the corresponding electrical signals to the electronic control system.

[0056] The electronic control system 18 is used to receive electrical signals sent by the first photodetector 171, the second photodetector 172, and the third photodetector 173, respectively, process the received electrical signals, and then substitute the processed electrical signals into a pre-edited correction and compensation system so that the pre-edited correction and compensation system can directly obtain the small displacement that we want to measure. The correction and compensation system is the system that edits in the corresponding formulas from formula (12) to formula (18) below.

[0057] In this embodiment, the laser synthesized wavelength measurement interferometer 1 based on fiber coupling optimization employs the principle of synthesized wavelength interference fringe subdivision to enable a dual-frequency laser with a large frequency difference to output two orthogonally linearly polarized beams. The two beams have wavelengths of... The laser beams, after exiting the composite laser source 11, are coupled together by the first fiber coupler 121 and then directed towards the first fiber beam splitter 131. After passing through the first fiber beam splitter 131, they are split into two groups of laser beams with equal intensity. The first group passes through the adjustable optical path reference fiber 15 and reaches the third fiber coupler 123, becoming the reference arm. The second group is directed towards the first polarization beam splitter 141, which re-splits the coupled laser beams. and , Directed towards the second fiber optic coupler 122, The measuring fiber 16, which allows for adjustable optical path length, is also directed to the second fiber coupler 122, becoming a measuring arm. In the second fiber optic coupler 122 with The two sets of coupled lasers from the reference arm and the measuring arm are recoupled in the third fiber coupler 123 and directed towards the second polarization beam splitter 142. The second polarization beam splitter 142 then splits the coupled lasers into two beams. and , Sensed by the first photodetector 171, The light is transmitted into the second fiber optic beam splitter 132, which then directs it to the second photodetector 172 and the third photodetector 173, respectively. Finally, the signals output by the first photodetector 171, the second photodetector 172, and the third photodetector 173 are controlled by the electronic control system 18. The optical signals received by the first photodetector 171, the second photodetector 172, and the third photodetector 173 are converted into corresponding electrical signals in their respective detectors and then sent to the electronic control system 18. The electronic control system 18 processes the received electrical signals and then feeds them into a pre-edited correction and compensation system. This pre-edited correction and compensation system can directly obtain the minute displacement that we want to measure. This minute displacement is the minute displacement of the adjustable optical path measuring fiber 16. (This will be explained later in the section on the principle of the laser synthesis wavelength measurement interferometer 1 based on fiber coupling optimization).

[0058] The correction and compensation system is the system that edits in the corresponding formulas from formula (12) to formula (18) in the following formulas.

[0059] The principle of the laser synthesis wavelength measurement interferometer 1 based on fiber coupling optimization is explained in detail below.

[0060] The laser synthesis wavelength measurement interferometer 1 based on fiber coupling optimization employs the principle of synthesized wavelength interference fringe subdivision to enable a dual-frequency laser with a large frequency difference to output two orthogonally linearly polarized beams. For example... Figure 1 As shown, the wavelength is The beam is directed toward a reference interferometer composed of a first fiber coupler 121, a first fiber beam splitter 131, a first polarization beam splitter 141, a second fiber coupler 122, a third fiber coupler 123, a second polarization beam splitter 142, and a first photodetector 171; the wavelength is... The beam is directed toward a measuring interferometer consisting of a first fiber coupler 121, a first fiber beam splitter 131, a first polarization beam splitter 141, a measuring fiber 16 with adjustable optical path 16, a second fiber coupler 122, a third fiber coupler 123, a second polarization beam splitter 142, a second fiber beam splitter 132, a second photodetector 172, and a third photodetector 173.

[0061] The interference signal is reflected by the second polarization beam splitter 142 and then detected by the first photodetector 171. The interference signal is split into two paths after passing through the second polarization beam splitter 142 and directed to the second photodetector 172 and the third photodetector 173 respectively. By setting the center positions of the second photodetector 172 and the third photodetector 173 to be separated by a quarter of the interference fringe spacing, two interference signals with a phase difference of 90° are obtained, and the measurement is completed.

[0062] Next, the principle will be described in detail. The adjustable optical path of the reference fiber 15 between the first fiber beam splitter 131 and the third fiber coupler 123 is called the reference arm optical path of the reference interferometer. Although the first fiber beam splitter 131 and the first polarization beam splitter 141 are in the measurement optical path, their positions do not actually change, so they are referred to as the fixed optical path of the reference interferometer, or simply the fixed optical path. ,remember The optical path difference is used as a reference in the interferometer.

[0063] As can be seen from the optical path diagram, when we set the wavelength to... The laser is adjusted so that its optical path length between the adjustable reference fiber 15 and the first polarization beam splitter 141 and the second fiber coupler 122 is multiple of the optical path length. At this time, the first photodetector 171 receives the wavelength. The phase of the interference signal is:

[0064] (3)

[0065] Figure 1 In the optical path shown, since the optical paths of the reference interferometer and the measuring interferometer overlap in the aforementioned reference arm optical path and fixed optical path, it is recorded as follows: To adjust the measurement optical path of the measuring fiber 16, the optical path difference in the measuring interferometer is: The wavelength received by the second photodetector 172 The phase of the interference signal is:

[0066] (4)

[0067] set up for and The phase difference between the two interference signals is:

[0068] (5)

[0069] For the synthesized wavelength:

[0070] (6)

[0071] It should be noted that the above-mentioned and They are perpendicular and orthogonal, therefore formed by them Unlike the real composite wavelength produced by typical optical beat frequency waves, here... Wavelengths that cannot be detected by photodetectors are called "virtual composite wavelengths".

[0072] When the measuring fiber 16, which can adjust the optical path, moves a tiny displacement... At that time, wavelength As the optical path changes, the phase difference between the two interference signals becomes the following equation:

[0073] (7)

[0074] In order to measure this tiny displacement The reference mirror can be moved. make Return to ,Right now And the reference mirror moves. Then, the phase difference between the two interference signals becomes as shown in the following equation:

[0075] (8)

[0076] Due to the movement of the reference mirror Post-satisfaction Combining the above formula, we have:

[0077] (9)

[0078] The optical path length in an optical fiber is determined by its refractive index and physical length, where n is the effective refractive index of the optical fiber. This represents the physical length of the optical fiber. Optical path length in an optical fiber:

[0079] (10)

[0080] In the principle described above, a composite wavelength is introduced to solve the phase ambiguity problem:

[0081] (11)

[0082] For ease of derivation, the relationship between optical path difference and phase difference in the above formula will be repeated once more in this principle:

[0083]

[0084] (12)

[0085]

[0086] Since the optical path length changes at this point, it should be multiplied by the effective refractive index (n) over all physical lengths of the optical path.

[0087] That is:

[0088] (13)

[0089] The above formula should be changed to:

[0090] (14)

[0091] In addition, we need to consider the potential increase in errors caused by the introduction of optical fibers. These errors will be explained one by one below, and solutions will be proposed.

[0092] To address the phase difference issue caused by birefringence in optical fibers, compensation or calibration is necessary to eliminate the error. The refractive index difference is... All optical paths that encounter this situation are collectively referred to as :

[0093] (15)

[0094] At the same time, the effects of temperature and strain on fiber length should also be taken into account. The coefficient of thermal expansion is For the changed temperature, The original length of each optical path segment, The actual length of each optical path after the change:

[0095] (16)

[0096] Furthermore, phase correction for fiber dispersion needs to be considered, where the group velocity refractive index is... The length of each optical path is Each wavelength is The corrected phase is :

[0097] (17)

[0098] (18)

[0099] The above formulas allow for a systematic analysis of the interferometer data and error correction after the synthesized wavelength is fiberized.

[0100] The technical solution of this utility model will be demonstrated below with a specific embodiment.

[0101] I. Experimental Setup

[0102] The experimental setup consists of two parts. The first part is the fiber optic circuit, which includes five 50:50 beam splitters, two polarization beam splitters corresponding to the wavelengths, two light sources corresponding to the wavelengths, and four pairs of optical fibers with variable lengths.

[0103] The first part is composed of fiber optics. The second part is the electronic control section, which mainly consists of three photodetectors, three STM32 boards, and three OLED screens.

[0104] It is formed by connecting the links.

[0105] II. Data Measurement and Analysis

[0106] This experiment set up three control groups and one reference group, according to the formula. It is known that the required correspondence needs to be set. Calculations show that, under these experimental conditions, The value is -0.154, therefore the corresponding experimental group is set up (as shown in Table 1 below):

[0107] Table 1. Data from the three control groups and one reference group.

[0108]

[0109] Analyze the values ​​in Table 1. For bright ring reference values, The measured value is for the bright ring. This is the reference value for the bright ring. For the measurement value of the bright ring:

[0110] (19)

[0111] The bright ring error was 0.833% and the dark ring error was 0.755%. Since the measured red light wavelength was 650 mm, the bright ring error of 0.833% and the dark ring error of 0.755% indicate that the difference from the predicted value is very small, and general measurement work can be completed. The measurement error is around 3.25 mm, thus completing the expected experiment.

[0112] Then, the uncertainty was assessed, including To measure the displacement of the arm length The average value, Displacement for reference arm length The average value, and The uncertainties for the two are as follows:

[0113] (20)

[0114] (twenty one)

[0115] Calculated from the above formula, It is 0.882. It is 0.032.

[0116] III. Conclusion

[0117] We conclude that: (1) By changing the optical path of the measuring arm, the measured data meets the expected results, that is, by reducing the interference of uncertain factors on the accuracy, we successfully converted it into an interference phenomenon under closed conditions. (2) The expected experimental goal was achieved. By measuring the small displacement through the interference of light, the small displacement at this time can be calculated in a controllable manner with an accuracy of 3.25 nm.

[0118] IV. Production Costs

[0119] The manufacturing cost of this specific embodiment is shown in Table 2.

[0120] Table 2 Production Cost Details

[0121]

[0122] In summary, the laser synthesis wavelength measurement interferometer 1 based on fiber coupling optimization provided by this utility model has the following technical advantages: (1) The measurement accuracy of this interferometer is improved due to the closed environment of the optical fiber;

[0123] (2) Since each fiber optic segment is replaceable, the damaged part of the interferometer can be replaced individually, which is convenient for maintenance personnel. (3) The combination of photoelectric and optical technologies makes the measurement method of the interferometer more convenient and the measurement results more reliable. (4) The manufacturing cost of the interferometer is not high, and it has a very promising market promotion value.

[0124] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A laser synthetic wavelength measurement interferometer based on fiber coupling optimization, characterized in that, include: The system comprises an interconnected composite laser source, an optical fiber coupler assembly, an optical fiber beam splitter assembly, a polarization beam splitter assembly, an adjustable optical path reference fiber, an adjustable optical path measurement fiber, a photodetector assembly, and an electronic control system; wherein the composite laser source emits two laser beams with wavelengths of λ1 and λ2 respectively. The fiber optic coupler assembly includes: a first fiber optic coupler, a second fiber optic coupler, and a third fiber optic coupler; the fiber optic beam splitter assembly includes: a first fiber optic beam splitter and a second fiber optic beam splitter; the polarization beam splitter assembly includes: a first polarization beam splitter and a second polarization beam splitter; the photodetector assembly includes: a first photodetector, a second photodetector, and a third photodetector. Wherein, the output end of the composite laser source is connected to the input end of the first fiber coupler; the output end of the first fiber coupler is connected to the input end of the first fiber beam splitter; the first output end of the first fiber beam splitter is connected to the input end of the adjustable optical path reference fiber; and the second output end of the first fiber beam splitter is connected to the input end of the first polarization beam splitter. The output end of the adjustable optical path reference fiber is connected to the first input end of the third fiber coupler; the first output end of the first polarization beam splitter is connected to the first input end of the second fiber coupler; the second output end of the first polarization beam splitter is connected to the input end of the adjustable optical path measurement fiber; and the output end of the adjustable optical path measurement fiber is connected to the second input end of the second fiber coupler. The output end of the second fiber coupler is connected to the second input end of the third fiber coupler; the output end of the third fiber coupler is connected to the input end of the second polarization beam splitter; the first output end of the second polarization beam splitter is connected to the input end of the first photodetector; the second output end of the second polarization beam splitter is connected to the input end of the second fiber beam splitter; the first output end of the second fiber beam splitter is connected to the input end of the second photodetector; the second output end of the second fiber beam splitter is connected to the input end of the third photodetector; the first photodetector, the second photodetector, and the third photodetector are respectively electrically connected to the electronic control system.

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