CN103900680B - A kind of device utilizing light source to suppress polarization crosstalk to measure noise and detection method - Google Patents

Abstract

The invention provides a device and a detection method for suppressing polarization crosstalk measurement noise by using a light source. The device consists of a wide-spectrum light source, a polarization device to be tested, an optical path correlator, a differential detection device, a photoelectric signal conversion and a signal recording device. Ratio polarizing device; the method is: a polarization state controller is connected between the light source and the polarizing device, and the polarizing angle of the linearly polarized light and the polarizing device are strictly coincident by adjusting the polarization state of the output light of the light source. The device combines a high polarization light source with a high extinction ratio polarization device to suppress the measurement noise in the optical coherence domain polarimeter by increasing the extinction ratio of the signal light injected into the device under test, and improve the measurement accuracy of the polarization characteristics of the device . The invention has the advantages of simple structure, excellent performance and easy adjustment, and can be widely used in the fields of high-precision measurement and analysis of optical properties of optical fiber type polarization maintaining devices and the like.

Description

A device and detection method for suppressing polarization crosstalk measurement noise by using light source

technical field

The invention relates to an optical fiber measurement device, in particular to a device for suppressing polarization crosstalk measurement noise by using a light source.

Background technique

Optical coherent domain polarization detection (OCDP) based on the principle of white light interference is one of the most promising optical fiber measurement technology solutions. According to the principle of white light interference, the structure of full polarization-maintaining optical fiber is adopted, and the optical fiber device can be coiled and the performance of the device is stable. The whole experimental device has the characteristics of small size and high stability. Optical coherent domain polarization (OCDP) compensates the optical path through the scanning Michelson interferometer to realize the interference between different coupling modes. It can locate the position of the internal defect of the optical fiber such as the mode coupling point, and analyze the coupling strength of the point by using the interference intensity. Therefore, OCDP technology has been successfully applied in the fields of polarization extinction ratio test, fiber optic gyro ring test, polarization maintaining fiber accuracy, polarization maintaining fiber manufacturing, polarization maintaining fiber axis alignment, device extinction ratio test, etc. And other similar technologies, such as Optical Time Domain Reflectometry (OTDR), Polarization Time Domain Reflectometry (POTDR), Optical Low Coherence Reflectometry (OLCR), Optical Frequency Domain Reflectometry (OFDR), Optical Coherent Domain Reflectometry (OCDR) Compared with other distributed detection methods and technologies, OCDP technology has simple structure (based on Mach-Zehnder or Michelson interferometer), high spatial resolution (several centimeters), large measurement range (several kilometers), ultra-high measurement sensitivity (coupling -90 ^～ -100dB), large dynamic range (10 ⁹ ～10 ¹⁰ ), etc. It is an inevitable trend for OCDP technology to develop into a high-precision, general-purpose testing technology and system in the future.

As early as the 1980s, foreign countries have started research on improving the accuracy of polarization detection. In the early 1990s, Herve Lefevre et al. of France (who first disclosed the OCDP system Method for the detection of polarization coupling in birefringent topical system and application of this method to the assembly of the components of the components of an optical system, US4893931 based on the principle of white light interference), which used superluminescent light-emitting diodes (SLD) as the light source and spatial interference optical path as the optical path correlation measurement structure. According to this patent, French Photonetics company has developed two types of OCDP test systems, WIN-P125 and WIN-P400, which are mainly used for the analysis of polarization characteristics of shorter (500m) and longer (1600m) polarization-maintaining optical fibers. Its main performances are polarization crosstalk sensitivity of -70dB and dynamic range of 70dB. The ICD800 launched by Korean Fiberpro is mainly used to replace the WIN-P series OCDP system, the spatial resolution is 10cm, the length of the scanning polarization-maintaining fiber is increased to 1000m, and the sensitivity is increased to -80dB.

In 2011, Yao Xiaotian and others from General Photonics Corporation of the United States disclosed an all-fiber measurement system (Measuring Distributed Polarization Crosstalkin Polarization Maintaining Fiber and Optical Birefringent Material, US20110277552) for measuring distributed polarization crosstalk in polarization maintaining fibers and optical birefringent materials. An optical path retarder is added before the detector to suppress the quantity and amplitude of stray white light interference signals during polarization crosstalk measurement. This method can improve the polarization crosstalk sensitivity of the all-fiber measurement system to -95dB, but maintain the dynamic range at 75dB.

In the same year, Zhang Hongxia of Tianjin University and others disclosed a detection method and detection device for the polarization extinction ratio of an optical polarization device (Chinese patent application number: CN201110052231.3). Coupling strength, the polarization extinction ratio is derived. The device is suitable for various optical polarization devices such as polarization-maintaining fiber, polarization-maintaining fiber coupler, and polarizer. Compared with the scheme of HerveLefevre et al., its technical performance and index are similar.

In 2012, the applicant disclosed an all-fiber test device for polarization crosstalk measurement of optical devices (Chinese patent application number: CN201210379406). This invention uses an all-fiber test device with high measurement accuracy and good temperature and vibration stability. High-precision measurement and analysis of polarization performance of optical devices. In the same year, the applicant disclosed a device and method for improving the performance of polarization crosstalk measurement of optical devices (Chinese patent application number: CN201210379407). This invention uses a Mach-Zehnder optical path correlator with polarization beam splitting function, and uses a fiber optic rotary connector , can greatly suppress the noise amplitude, and improve the sensitivity and dynamic range of the polarization crosstalk measurement to -95dB and 95dB respectively.

In the optical coherent domain polarization measurement technology, the polarization performance of the device under test—the polarization crosstalk information is mainly reflected in the peak amplitude of the interference signal and the optical path position: the former is proportional to the power coupling factor amplitude of the crosstalk, and the latter is related to the device Corresponds to where the crosstalk occurs in the middle. In an ideal situation, after the pure linearly polarized light emitted by the light source passes through the device under test, only one polarization coupling occurs at the defect, and its power is proportional to the power of the transmitted light and the size of the crosstalk. If the light source does not have ideal linear polarization characteristics, while the main polarization direction (long axis of elliptically polarized light) causes polarization crosstalk, polarization coupling will also occur in its orthogonal polarization direction (short axis of elliptically polarized light) , and the interference peak at this time is usually considered as optical noise for the measurement. The overlapping of optical noise and the polarization crosstalk signal of the device will inevitably lead to misjudgment of the performance of the device under test, and then have a serious impact on the accuracy of polarization measurement in the optical coherence domain. If the light energy in the vertical direction of the light source is not limited, the amount of optical noise will increase and the amplitude will increase, which will cause the polarization crosstalk signal of high-performance devices to be indistinguishable, and equivalently reduce the measurement sensitivity.

If in the existing all-fiber test device, by changing the structure and composition of the light source, the introduction of polarization noise is suppressed at the source, and efforts are made to increase the degree of polarization of the light source, so that the tiny polarization coupling strength of the vertical light component in the elliptically polarized light of the light source is sufficiently low To achieve the purpose of suppressing optical noise and improving the measurement accuracy of the system, it has great practical value for optical coherent polarization measurement.

Contents of the invention

The purpose of the present invention is to provide a device that can improve the measurement accuracy of the polarization characteristics of the device, has a simple structure, excellent performance, and is easy to adjust, and uses a light source to suppress polarization crosstalk measurement noise. Another object of the present invention is to provide a method for suppressing polarization crosstalk measurement noise by using a light source.

The purpose of the present invention is achieved like this:

The device for suppressing polarization crosstalk measurement noise by using a light source of the present invention includes a wide-spectrum light source 100, a polarization device to be measured 110, an optical path correlator 120, a differential detection device 130, and a photoelectric signal conversion and signal recording device 140; the wide-spectrum light source 100 includes A low-coherence light source 101 with a high degree of polarization, a polarization state controller 102, and a polarizing device 103. The low-coherence light source 101 with a high degree of polarization is adjusted by the polarization state controller 102 and then connected to the polarization device 103 to output linearly polarized light with a high degree of polarization; The linearly polarized light of the degree of polarization enters the optical path correlator 120 through the first rotary connector 111, the optical fiber device 112 to be tested, the second rotary connector 113, and the polarizer 114 in sequence; the polarizer 114 passes through the input port 1a and the first 1 Coupler 121 is connected, and the output ports 1c and 1d of the first coupler 111 are respectively connected with the scanning arm 1A and the reference arm 1B in the two interference arms of the optical path correlator 110; the light scans through the displacement scanning device 125, and the reference The light in the arm 1B merges and interferes at the two input ports 1e and 1f of the second coupler 122; the two output ends of the second coupler 122 are finally connected to the differential detection device 130; after the difference, the signal is input to the interference signal detection and The processing device 140 performs the analysis.

The device of the present invention for suppressing polarization crosstalk measurement noise by light source may also include:

1. The polarization state controller 102 is composed of an input optical fiber 2a, a first optical fiber ring 21, a second optical fiber ring 22, a third optical fiber ring 23, and an output optical fiber 2b, and both the input optical fiber 2a and the output optical fiber 2b are single-mode optical fiber.

2. The polarization state controller 102 is composed of an input optical fiber 3a, an optical fiber squeezer 31, an optical fiber twister 32, and an output optical fiber 3b. Polarization control is realized by extrusion and twisting, and its input optical fiber 3a and output optical fiber 3b are both single-mode fiber.

3. The polarizer 103 is a waveguide polarizer 6 made of lithium niobate crystal material, the waveguide chip 62 only supports the transmission of a guided mode in one polarization direction, and has a very high extinction ratio, ≥80dB; input The optical fiber 61 is a single-mode optical fiber, and the output optical fiber 63 is a polarization-maintaining optical fiber.

The method for utilizing the light source to suppress the polarization crosstalk measurement noise of the present invention is:

1. Inject the wide spectral range and highly linearly polarized light emitted by the high-polarization low-coherence light source 101 into the 1×2 fiber coupler 104, connect the first output end to the first photodetector 105, and perform corresponding state monitoring, The second output terminal is connected to the polarization state controller 102 and the polarization device 103;

2. Adjust the polarization state controller 102 to change the long-axis angle of the output light of the low-coherence light source 101 with high polarization degree, so that the light intensity reaches the maximum after passing through the polarizing device 103;

3. Adjust the angle between the waveguide chip 62 and the output optical fiber 63, so that the two are aligned in the direction of the fast axis or the slow axis, and welded at the solder joint 106, and the error is less than 0.2°;

4. The linearly polarized light emitted by the low-coherence light source 101 with a high degree of polarization after being adjusted by related devices passes through the polarization device 110 to be tested, the optical path correlator 120, and the differential detection device 130 in sequence, and the signal after the difference is input to the interference signal detection and detection device. The processing device 140 performs the analysis.

The invention mainly introduces a light source structure with the function of suppressing polarization crosstalk measurement noise. The wide-spectrum light source is a low-coherence light source with a high degree of polarization. A polarizing device with a high extinction ratio is placed behind the light source; a polarization state controller is connected between the light source and the polarizing device. By adjusting the polarization state of the output light of the light source, the linearly polarized light Strictly coincides with the polarizing angle of the polarizer. The device combines a high polarization light source with a high extinction ratio polarization device to suppress the measurement noise in the optical coherence domain polarimeter by increasing the extinction ratio of the signal light injected into the device under test, and improve the measurement accuracy of the polarization characteristics of the device . The invention has the advantages of simple structure, excellent performance, easy adjustment, etc., and can be widely used in the fields of high-precision measurement and analysis of the optical performance of fiber-optic polarization-maintaining devices.

The invention is a technical improvement of the light source structure in an all-fiber test device (OCDP) for polarization crosstalk measurement of typical optical devices, so that it has the function of suppressing polarization crosstalk measurement noise.

Ideally, only when the light input into the optical coherent domain polarization measurement device is strictly linearly polarized light, that is, the extinction ratio PER _s = ∞, can the test extinction ratio PER of the test device be equal to the real extinction ratio PER _chip of the device . However, this ideal situation cannot be realized. By continuously increasing the extinction ratio of the light source output, the test extinction ratio is continuously approaching the real value of the device.

In a typical all-fiber test device for polarization crosstalk measurement of optical devices (Fig. 4), the light source part only has a wide-spectrum light source SLD and a fiber polarizer. It is difficult for the emitted natural light 5a to form theoretically linearly polarized light after passing through the fiber polarizer P1, but an elliptically polarized light (5b) with a smaller ellipticity angle _θ1 . Its extinction ratio is

${\mathrm{<span\; class="notranslate">\; PER</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 101</span>}\mathrm{<span\; class="notranslate">\; g</span>}{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

The ellipticity angle _θ1 is closely related to the characteristics of the fiber polarizer P1. The elliptically polarized light with θ ₁ is directly sent to the optical path correlator through the polarization device to be tested for testing, and the obtained test extinction ratio PER is greatly affected by PER ₁ . Moreover, the polarization degree of domestic SLD light sources is about 40%, and it fluctuates with changes in the external environment, which will lead to polarization phase errors.

In the device using a light source to suppress polarization crosstalk measurement noise (see Figure 1), the broadband light source is a polarized light source with a high degree of polarization, and the light emitted by it can already be regarded as elliptically polarized light with a small ellipticity angle θ ₂ 5c, through the axis adjustment of the polarization state controller, the long axis passes through the polarization device P2, and the ideal linearly polarized light (5d) is obtained. The total extinction ratio is

PER ₂ =PER _s +PER _p (2) Among them, PER _s is the extinction ratio of the polarized light source, and PER _p is the extinction ratio of the polarizing device.

From the formula (1), the test extinction ratio PER is affected by the performance of the fiber polarizer, and the low-quality fiber polarizer directly reduces the accuracy of the test extinction ratio PER; from the formula (2), the test extinction ratio PER is affected by the polarized light source The performance of the sum of the extinction ratio of the polarizer and the polarization device, through the selection of the two, can continuously improve the accuracy of the test extinction ratio PER, reduce the influence of other noises, and make the test results approach the real extinction ratio PER _chip .

Through the improvement of the light source structure, the combination of high polarization light source and fiber optic polarization device with high extinction ratio improves the polarization characteristics of the light source and related devices from the root, and improves the quality of polarized light input into the polarization device under test: from a lower 40dB Increased to over 98dB. The purpose of suppressing the overall polarization crosstalk noise of the system and improving the measurement accuracy of the polarization crosstalk of the optical coherent domain polarimeter is achieved.

Compared with prior art, the present invention has following advantage:

(1) Compared with the low-polarization wide-spectrum light source, this scheme uses a high-polarization wide-spectrum light source. Starting from the source, the polarization performance of the test light source is improved, and the suppression effect on the optical noise of the test system is obvious;

(2) Using a high-performance polarizer and combining it with a high-polarization low-coherence light source further improves the polarization performance of the signal light injected into the device under test, and greatly suppresses the probability and magnitude of optical noise. Without changing other hardware, the sensitivity and accuracy of polarization measurement in the optical coherent domain are improved;

(3) The full-fiber polarization state modulation device is used, and there is no breakpoint in the optical path, which can realize the adjustment of the full polarization state of the light source without introducing new optical noise;

(4) The test system adopts an all-fiber optical path, which has the advantages of small size, high measurement accuracy, good temperature stability and anti-vibration stability.

Description of drawings

FIG. 1 is a device and method for suppressing polarization crosstalk measurement noise by using a light source;

Fig. 2 is a schematic diagram of a three-rotating paddle polarization controller with an all-fiber structure;

3 is a schematic diagram of an in-line polarization controller with an all-fiber structure;

Fig. 4 is a schematic diagram of an all-fiber test device for measuring polarization crosstalk of a typical optical device;

Fig. 5 is a schematic diagram of the change of the polarization characteristics of the light source through the polarizing device;

Fig. 6 is a schematic structural diagram of a waveguide polarizer made of lithium niobate crystal material.

detailed description

The present invention will be described in more detail below with examples in conjunction with the accompanying drawings, but the protection scope of the present invention should not be limited by this.

Referring to FIG. 1 , the device for suppressing polarization crosstalk measurement noise by using a light source of the present invention includes a broadband light source 100 , a polarizing device 110 to be measured, an optical path correlator 120 , a differential detection device 130 , and a photoelectric signal conversion and signal recording device 140 .

The wide-spectrum light source 100 is composed of a low-coherent light source 101 with a high degree of polarization, a polarization state controller 102, and a polarizing device 103; sum of extinction ratios.

The low-coherence light source 101 with a high degree of polarization has a wide spectral range and high linearly polarized light (extinction ratio ≥ 18dB) output; the external output fiber is a single-mode fiber.

The polarizer 103 is a waveguide polarizer 6 made of lithium niobate crystal material; the waveguide chip 62 only supports the transmission of a guided mode in one polarization direction, and has a very high extinction ratio (≥80dB); the input fiber 61 is A single-mode fiber, the output fiber 63 is a polarization-maintaining fiber.

The low-coherent light source 101 with a high degree of polarization is regulated by a polarization state controller 102 and connected with a polarizing device 103 to output linearly polarized light with a high degree of polarization.

In the optical coherent domain polarization measurement device, the linearly polarized light emitted by the low-coherence light source 101 with a high degree of polarization after being adjusted by related devices passes through the first rotary connector 111, the optical fiber device 112 to be tested, the second rotary connector 113, The polarizer 114 enters the optical path correlator 120; it is connected to the first coupler 121 through the input port 1a; the output ports 1c and 1d of the first coupler 111 are respectively connected to the The scanning arm 1A is connected to the reference arm 1B; the light is scanned by the displacement scanning device 125, and interferes with the light in the reference arm 1B at the two input ports 1e and 1f of the second coupler 112; the two outputs of the second coupler 112 The terminal is finally connected to the differential detection device 130; after the differential signal is input to the interference signal detection and processing device 140 for analysis.

A scheme of the polarization state controller 102 described in conjunction with FIG. 2 is a three-rotating paddle polarization controller with an all-fiber structure, which does not contain optical discontinuities; it consists of an input optical fiber 2a, a first optical fiber ring 21, a second optical fiber ring 22, the third optical fiber ring 23, and the output fiber 2b, which can convert the optical signal of any polarization state into other arbitrary polarization state optical signals in function; the structure is similar to a 1/4λ wave plate connected in series, a 1/4λ 2λ wave plate and a 1/4λ wave plate; all polarization state control can be realized through the mutual cooperation of three fiber ring swing adjustments; the input optical fiber 2a and output optical fiber 2b are both single-mode optical fibers.

Another scheme of the polarization state controller 102 described in conjunction with FIG. 3 is a squeezed twisted optical fiber structure, which is composed of an input optical fiber 3a, an optical fiber squeezer 31, an optical fiber twister 32, and an output optical fiber 3b; , to achieve polarization control; its input fiber 3a and output fiber 3b are both single-mode fibers.

A method for suppressing polarization crosstalk measurement noise by using a light source, characterized in that:

1) Inject the wide spectral range and highly linearly polarized light emitted by the high-polarization low-coherence light source 101 into the 1×2 fiber coupler 104, and connect the first output end to the first photodetector 105 for corresponding state monitoring, The second output terminal is connected to the polarization state controller 102 and the polarization device 103;

2) Adjust the polarization state controller 102 to change the long-axis angle of the output light of the low-coherence light source 101 with high polarization degree, so that the light intensity reaches the maximum after passing through the polarizing device 103;

3) Adjust the angle between the waveguide chip 62 and the output optical fiber 63 so that the two are aligned in the direction of the fast axis (or slow axis), and welded at the solder joint 106, with an error of less than 0.2°;

4) The linearly polarized light emitted by the low-coherence light source 101 with a high degree of polarization after being adjusted by related devices passes through the polarization device 110 to be tested, the optical path correlator 120, and the differential detection device 130 in sequence, and the signal after the difference is input to the interference signal detection and The processing device 140 performs the analysis.

The main device selection and parameters of the optical coherent domain polarization measurement device are as follows:

1) The central wavelength of the polarized light source is 1550nm, the half-spectrum width is greater than 30nm, the fiber output power is greater than 5mW, and the extinction ratio is 18dB;

2) Three-rotating paddle polarization controller with all-fiber structure, the fiber ring diameter is 27mm, the paddle rotation angle range is ±117.5°, and the bending loss is less than 0.1dB;

3) The polarization device is a waveguide polarizer made of lithium niobate crystal material. The front end of the pigtail is connected to a single-mode fiber, and the rear end is connected to a polarization-maintaining fiber. The fast axis of the waveguide is aligned with the fast axis of the polarization-maintaining fiber. The extinction ratio of the chip is 80dB;

4) The beam splitting ratio of 1×2 fiber coupler is 2:98, and the working wavelength is 1550nm;

5) The optical fiber device to be tested is a 200m Panda-type polarization-maintaining optical fiber;

6) The central wavelength of the movable optical mirror is 1550nm, the diameter is 20mm, the thickness is 2mm, and the average reflectivity is greater than 95%;

7) The operating wavelength of the three-port circulator is 1550nm, the insertion loss is 1dB, and the isolation is greater than 50dB;

8) The working wavelength of the collimating lens is 1550nm, and the insertion loss is 2dB, and the loss fluctuation is less than 0.2dB within the scanning range of the translation stage from 0 to 200mm;

9) The beam splitting ratio of the 2×2 fiber coupler is 50:50, and the working wavelength is 1550nm.

The working process of the test device is as follows:

The output light of the polarized light source 101 is split by the 1×2 fiber coupler 104, a small part of the energy is output from the detector 105 for monitoring, and most of the light reaches the polarization device 103 after the precise adjustment of the polarization state controller 102, and the output line of the polarization device 103 The polarized light is welded at 0° with the rear polarized optical fiber at the fast axis (or slow axis) at the welding point (106), so as to obtain relatively pure linearly polarized light.

Through the rotary connector 111, the precise 45° alignment is to the slow axis of the input end of the polarization-maintaining fiber of the device under test, and the optical signal is output through the pigtail through the 45° rotary connector 113; the light is mixed in the optical fiber analyzer 114, and passed through The 2×2 fiber coupler 121 is evenly divided into two beams, and enters the two arms of the optical path correlator 120; the light in the scanning arm 1A is scanned by the optical path of the displacement scanning device 125, and the optical path generated between the two arms is When the difference matches the transmission signal with different optical path differences to be measured, the difference detection device 130 outputs a white light interference signal; finally, after the difference, the signal is input to the interference signal detection and processing device 140 for result analysis. Its interference peak is proportional to the amplitude of the optical signal to be measured, and the corresponding optical path scanning position is proportional to the optical path of the signal to be measured.

From formula (2), the extinction ratio of light entering the device under test at 106 solder joints is PER ₂ =18+80=98dB.

It is worth noting that 1) the front end of the polarizing device 103 must be precisely aligned with the light passing through the polarization state controller 102: the long axis of the elliptically polarized light emitted by the polarized light source is highly coincident with the inherent fast axis (or slow axis) of the polarizing device, It is shown that the light intensity reaches the maximum value after the light passes through the polarizing device 103; 2) The rear end of the polarizing device 103 must be precisely aligned with the polarization-maintaining fiber at the welding point 106: the inherent fast axis (or slow axis) of both the polarizing device and the polarization-maintaining fiber axis) highly coincident.

The alignment accuracy of the polarizer has a great impact on the polarization state of the entire light source section. In order to improve the measurement accuracy of polarization crosstalk of optical coherence domain polarimeter, while improving the light source structure, attention should also be paid to the alignment error between each optical device.

Claims (4)

1. A device for suppressing polarization crosstalk measurement noise by using a light source, comprising a wide-spectrum light source (100), a polarization device to be measured (110), an optical path correlator (120), a differential detection device (130), an interference signal detection and A processing device (140); it is characterized in that: the wide-spectrum light source (100) includes a low-coherence light source (101) with a high degree of polarization, a polarization state controller (102), a polarization device (103), and a low-coherence light source with a high degree of polarization ( 101) Adjust the polarization state controller (102) and then connect with the polarization device (103) to output linearly polarized light with a high degree of polarization; the linearly polarized light with a high degree of polarization passes through the first rotary connector (111) and the optical fiber device to be tested in sequence (112), the second rotary connector (113), and the analyzer (114) enter the optical path correlator (120); the analyzer (114) is connected with the first coupler (121) through the input port (1a) , the output ports (1c), (1d) of the first coupler (111) are respectively connected to the scanning arm (1A) and the reference arm (1B) in the two interference arms of the optical path correlator (110); The scanning device (125) scans and interferes with the light in the reference arm (1B) at the two input ports (1e, 1f) of the second coupler (122); the two output ports of the second coupler (122) finally It is connected with the differential detection device (130); after the differential signal is input to the interference signal detection and processing device (140) for analysis, the polarizer (103) is a waveguide polarizer (6) made of lithium niobate crystal material , the waveguide chip (62) only supports the transmission of a guided mode in one polarization direction, and has a very high extinction ratio, ≥80dB; the input fiber (61) is a single-mode fiber, and the output fiber (63) is a polarization-maintaining fiber. 2. the device utilizing light source to suppress polarization crosstalk measurement noise according to claim 1, is characterized in that: described polarization controller (102) is input optical fiber (2a) by polarization controller, the first fiber ring ( 21), the second optical fiber ring (22), the third optical fiber ring (23), the polarization state controller output fiber (2b), the polarization state controller input fiber (2a) and the polarization state controller output fiber (2b) are both for single-mode fiber. 3. the device utilizing light source to suppress polarization crosstalk measurement noise according to claim 1, is characterized in that: described polarization controller (102) is input optical fiber (3a) by polarization controller, fiber squeezer ( 31), an optical fiber twister (32), and a polarization state controller output fiber (3b), the polarization control is realized by squeezing and twisting, the polarization state controller input fiber (3a) and the polarization state controller output fiber (3b) are both for single-mode fiber. 4. a method utilizing the device of claim 1 to suppress polarization crosstalk measurement noise utilizing light source to detect noise, is characterized in that: 1) Inject the wide spectral range and highly linearly polarized light emitted by the low-coherence light source (101) with high polarization degree into the 1×2 fiber coupler (104), and connect the first output end to the first photodetector (105), Carrying out corresponding state monitoring, the second output terminal is sequentially connected to a polarization state controller (102) and a polarization device (103); 2) adjusting the polarization state controller (102), changing the long-axis angle of the output light of the low-coherence light source (101) with high polarization degree, so that the light intensity reaches the maximum after passing through the polarizing device (103); 3) Adjusting the angle of the waveguide chip (62) and the output optical fiber (63), so that the two are aligned in the direction of the fast axis or the slow axis, and welded at the solder joint (106), the error is less than 0.2°; 4) The linearly polarized light emitted by the low-coherence light source (101) with a high degree of polarization after being adjusted by related devices passes through the polarization device to be measured (110), the optical path correlator (120), and the differential detection device (130) in sequence, and passes through the differential The final signal is input to the interference signal detection and processing device (140) for analysis.