A device for measuring distributed optical polarization crosstalk in an ultra-wide spectral range

Abstract

The present invention discloses a device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range. The device includes an ultra-wideband light source module, an optical path modulation and demodulation module, a signal detection and processing module, and a device under test. The ultra-wideband light source module provides input optical signals with different central wavelengths, which are injected into and emitted from the device under test at both ends. After passing through the ultra-wideband light source module, these signals are received by the optical path modulation and demodulation module. Based on the principle of white light interferometry, the device simultaneously obtains and converts ultra-wideband white light interference signals into electrical signals by adjusting the optical path difference of the optical path modulation and demodulation modules. The signal detection and processing module calculates the ultra-wideband polarization characteristics of the device under test corresponding to the ultra-wideband light source module based on the electrical signals. This device can effectively broaden the measurement wavelength range of distributed polarization crosstalk in optical devices, effectively improve measurement efficiency, and reduce measurement device costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical measurement, and relates to a device for measuring distributed polarization crosstalk of an optical device, and in particular to a device for measuring distributed optical polarization crosstalk in an ultra-wide spectral range. Background Art

[0002] Research on optical coherence domain polarization property measurement began in the 1990s and has been widely studied due to its advantages, including ultra-high polarization measurement sensitivity, high spatial resolution, wide measurement dynamic range, and measurable optical path length. In 2013, Yang Jun et al. from Harbin Engineering University published an all-fiber test device for polarization crosstalk measurement in optical devices (ZL201210379406.6). This device addresses several key technical challenges in high-precision white-light interferometry, maintaining a dynamic range of 95 dB for polarization crosstalk measurement while reducing the test system size and improving measurement stability. This device lays the foundation for high-precision measurement and analysis of distributed polarization crosstalk in optical devices.

[0003] Currently, the commonly used wavelength bands for fiber-optic communications are the 850nm band (850nm-Band), the O-band (Original Band: 1260-1360nm), the E-band (Extended-wavelength Band: 1360-1460nm), the S-band (Short-wavelength Band: 1460-1530nm), the C-band (Conventional Band: 1530-1565nm), the L-band (Long-wavelength Band: 1565-1625nm), and the U-band (Ultra-long-wavelength Band: 1625-1675nm). For inertial navigation systems, different types of fiber-optic gyros (FOGs) operate at different wavelengths. Measuring the polarization characteristics of the core optical components of FOGs operating at different wavelengths can accurately evaluate their performance. Integrated waveguide modulators and polarization-maintaining fiber rings, the core optical components of fiber gyros, operate in multiple wavelength bands, including 850nm, 1310nm, and 1550nm. Devices with different operating wavelengths are also customized for special needs. Testing and evaluating the distributed polarization crosstalk of fiber gyro core optical components, and thereby improving the manufacturing process, are of great significance for optimizing the performance of fiber gyro systems. In 2017, Yang Jun et al. from Harbin Engineering University disclosed a dual-channel simultaneous optical performance test device for Y-waveguide devices and a method for identifying and processing Y-waveguide polarization crosstalk (ZL201410535202.6). This method uses white-light interferometry to obtain the extinction ratio of integrated waveguide chips, enabling high-precision, wide-dynamic-range polarization characteristic testing and simultaneous measurement of distributed polarization crosstalk in two Y-waveguide channels. In 2020, Yang Jun and others from Harbin Engineering University disclosed a device and method for bidirectional simultaneous measurement of distributed polarization crosstalk in a polarization-maintaining fiber ring (ZL202010748503.2). This method uses white light interferometry technology to obtain distributed polarization crosstalk in a polarization-maintaining fiber ring, which can reduce the difference in forward and reverse measurements, and has high measurement accuracy and reliability. It can be used for bidirectional measurement of distributed polarization crosstalk, reciprocity evaluation, and ring symmetry evaluation of polarization-maintaining fiber rings.

[0004] However, the above-mentioned solutions for measuring the distributed polarization crosstalk of optical devices all measure the polarization characteristics of the optical device under an input optical signal of a single central wavelength provided by a broadband light source, and cannot meet the requirements for measuring the polarization characteristics of the optical device under input optical signals of different central wavelengths. The slight differences in the performance parameters of the same optical device at different central wavelengths will cause relatively serious measurement errors in the polarization characteristics measurement. Therefore, it is necessary to build a measurement device at the corresponding central wavelength of the optical device to measure its distributed polarization crosstalk. Considering the cost and measurement efficiency of building a measurement device, there is still a lack of an accurate and effective device that can simultaneously measure the distributed polarization crosstalk of optical devices over an ultra-wide spectral range. Summary of the Invention

[0005] To address the problem of measuring distributed polarization crosstalk in optical devices over an ultra-wide spectral range, the present invention provides a device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range. This device accurately and simultaneously measures the ultra-wideband polarization characteristics of the device under test across an ultra-wide spectral range, effectively expanding the wavelength range for measuring distributed polarization crosstalk in optical devices, improving measurement efficiency, and reducing measurement device costs.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A device for measuring distributed optical polarization crosstalk in an ultra-wide spectral range includes an ultra-wideband light source module, an optical path modulation and demodulation module, a signal detection and processing module, and a device to be measured, wherein:

[0008] The ultra-wideband light source module provides input optical signals with different central wavelengths, which are injected from both ends of the device under test and emitted from the device under test. After passing through the ultra-wideband light source module, they are received by the optical path modulation and demodulation module. Based on the principle of white light interferometry, by adjusting the optical path difference of the optical path modulation and demodulation modules, ultra-wideband white light interference signals are simultaneously obtained and converted into electrical signals. The signal detection and processing module calculates the ultra-wideband polarization characteristics of the device under test corresponding to the ultra-wideband light source module based on the electrical signals.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] 1. The measurement device of the present invention is based on a Mach-Zehnder interferometer. Based on the principle of symmetry, several optical wavelength division multiplexers are added to the optical path structure to effectively broaden the measurement wavelength range of distributed polarization crosstalk of optical devices. At the same time, the input optical signal is injected from both ends of the device to be measured, further doubling the measurement wavelength range of distributed polarization crosstalk of optical devices, simplifying the optical path structure and reducing the cost of the measurement device.

[0011] 2. When measuring the polarization characteristics of optical devices at different central wavelengths, the same optical path scanner and optical interferometer are used to reduce the inconsistency of ultra-wideband polarization characteristic measurements of optical devices and improve measurement accuracy.

[0012] 3. Without the need for complex measurement processes, the ultra-wide-band white light interference signal of the optical device can be obtained simultaneously, and the ultra-wide-band polarization characteristics of the device under test corresponding to the ultra-wide-band light source module can be obtained, thereby improving measurement efficiency.

[0013] 4. Use the differential detection method to eliminate the influence of the DC term of the white light interference signal and improve the signal-to-noise ratio of the device.

[0014] 5. The measuring device of the present invention is constructed using an optical fiber optical path, and has the advantages of being small in size, being almost unaffected by airflow and ambient light, and having good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the measurement device for distributed optical polarization crosstalk over an ultra-wide spectral range;

[0016] Figure 2 This is a schematic diagram of a white light coherent domain polarization measurement device based on Mach-Zehnder interferometer;

[0017] Figure 3 It is the optical transmission path diagram of the optical signal in the ultra-wideband light source module;

[0018] Figure 4 This is the signal separation path diagram of the ultra-wideband white light interference signal in the optical path modulation and demodulation module;

[0019] Figure 5 This is the schematic diagram of the dual-wavelength distributed optical polarization crosstalk simultaneous measurement device. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below with reference to the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0021] The present invention is a technical improvement to the optical coherence domain polarization measurement system (OCDP) based on the white light interference principle. The working principle of the white light coherence domain polarization measurement device based on Mach-Zehnder interferometer is as follows: Figure 2As shown, taking the measurement of the polarization characteristics of the polarization-maintaining fiber as an example, the broadband light source 51 provides highly stable broadband polarized light, and the input optical signal I0 after passing through the polarizer 52 is injected into the slow axis of the polarization-maintaining fiber 53 to be measured (the principle is the same for the fast axis). When the input optical signal 601 passes through the perturbation point 602 in the polarization-maintaining fiber 53 to be measured (formed by internal defects or external pressure, etc.), a part of the optical energy of the optical signal in the slow axis will be coupled to the orthogonal fast axis to form coupled light ρI0, where ρ is the polarization coupling coefficient, and the remaining transmitted light I0 (1-ρ) is still transmitted along the slow axis. When the optical signal is emitted from the output end of the polarization-maintaining fiber 53 to be measured, due to the linear birefringence Δn (for example: 5×10 -4 ), resulting in an optical path difference Δnl between the transmission light 603 in the slow axis and the coupled light 604 in the fast axis (the distance from the perturbation point 602 to the output end of the polarization-maintaining fiber 53 to be measured is l). After being polarized by the analyzer 54, the transmission light 603 and the coupled light 604 are evenly split into two parts by the third 2×2 fiber coupler 55. One portion of the optical signal is transmitted as a reference optical signal to the fourth 2×2 fiber coupler 56, while the other portion of the optical signal passes through the fiber circulator 231 and is transmitted to the fiber collimating lens 232. The optical signal received by the fiber collimating lens 232 is reflected by the optical path scanner 233, outputted from the fiber collimating lens 232, and transmitted as a scanned optical signal to the fourth 2×2 fiber coupler 56.

[0022] When the optical path difference is equal to Δnl, the peak amplitude of the white light interference signal formed by the interference of the reference light signal and the scanning light signal is When the optical path difference is equal to 0, the peak amplitude of the white light interference signal formed by the interference of the reference light signal and the scanning light signal is I main ∝I0, when the optical path difference is equal to -Δnl, the peak amplitude of the white light interference signal formed by the interference of the reference light signal and the scanning light signal is Compared with the case where the optical path difference is Δnl, this white light interference signal is symmetrical in the optical path and has the same amplitude.

[0023] The polarization coupling coefficient ρ can be obtained based on the white light interference signal amplitude I obtained by the optical path difference Δnl or -Δnl coupling , and the white light interference signal amplitude I is obtained when the optical path difference is 0 main Calculation yields:

[0024]

[0025] The fifth detector 57 detects the white light interference signal formed by the interference of the reference light signal and the scanning light signal and converts it into an electrical signal. The signal acquisition and processing unit 31 receives the electrical signal and transmits it to the computer 32 via the data transmission line. The computer 32 uses the polarization crosstalk detection and processing algorithm to detect the white light interference signal converted into an electrical signal, and obtains the polarization coupling coefficient ρ based on formula (1), and finally obtains the polarization characteristics of the polarization-maintaining optical fiber 53 to be tested. When there are multiple perturbation points in the device to be tested, the white light interference signal formed by the interference between the transmitted light and the different coupled lights will be distributed according to the optical path difference. Therefore, the above test scheme can perform distributed measurement of the polarization characteristics of the optical device, but it can only meet the polarization characteristic measurement of the optical device under the input light signal of a single central wavelength provided by the broadband light source, and cannot meet the polarization characteristic measurement of the optical device under the input light signal of different central wavelengths. The slight difference in performance parameters of the same optical device at different central wavelengths will bring more serious measurement errors to the polarization characteristic measurement. Considering the cost and efficiency of building a measurement device, it is necessary to build an accurate and effective device that can simultaneously measure the distributed polarization crosstalk of optical devices in an ultra-wide spectral range.

[0026] In order to solve the above technical problems, the present invention provides a device for measuring distributed optical polarization crosstalk in an ultra-wide spectral range, such as Figure 1 As shown, the device includes an ultra-wide-band light source module 1, an optical path modulation and demodulation module 2, a signal detection and processing module 3, and a device under test 41, wherein: the ultra-wide-band light source module 1 provides input light signals with different central wavelengths, which are respectively injected from both ends of the device under test 41 and emitted from the device under test 41, and are received by the optical path modulation and demodulation module 2 after passing through the ultra-wide-band light source module 1; based on the principle of white light interferometry, by adjusting the optical path difference of the optical path modulation and demodulation module 2, an ultra-wide-band white light interference signal is obtained at the same time and converted into an electrical signal; the signal detection and processing module 3 calculates the ultra-wide-band polarization characteristics of the device under test 41 corresponding to the ultra-wide-band light source module 1 according to the electrical signal.

[0027] Example 1:

[0028] This embodiment provides a device for simultaneously measuring distributed optical polarization crosstalk over an ultra-wide spectral range. Figure 1 As shown, the device includes a dual-wavelength broadband light source module 1, an optical path modulation and demodulation module 2, a signal detection and processing module 3, and a device under test 41, wherein:

[0029] The ultra-wideband light source module 1 includes an nath wide-spectrum light source 13(n), an nbth wide-spectrum light source 18(n), an nath wavelength division multiplexer 11(n), an nbth wavelength division multiplexer 12(n), a first 1×n fiber coupler 14, a second 1×n fiber coupler 15, a third 1×n fiber coupler 16, and a fourth 1×n fiber coupler 17;

[0030] The nath wavelength division multiplexer 11 (n) is provided with a first port 11 (n) a, a second port 11 (n) b and a third port 11 (n) c;

[0031] The nb-th wavelength division multiplexer 12 (n) is provided with a first port 12 (n) a, a second port 12 (n) b and a third port 12 (n) c;

[0032] The nath broad spectrum light source 13(n) provides the nath input optical signal I na , I na The light enters the nth wavelength division multiplexer 11(n) through the first port 11(n)a of the nth wavelength division multiplexer 11(n), is coupled by the nth wavelength division multiplexer 11(n), enters the first 1×n optical fiber coupler 14 through the third port 11(n)c of the nth wavelength division multiplexer 11(n), and is injected into the device under test 41. After exiting the device under test 41, the light enters the second 1×n optical fiber coupler 15. na The signals enter the nb-th wavelength division multiplexer 12(n) through the third port 12(n)c of the nb-th wavelength division multiplexer 12(n), and after separation by the nb-th wavelength division multiplexer 12(n), I na The optical signal enters the fourth 1×n optical fiber coupler 17 from the second port 12 (n) b, and the optical path modulation and demodulation module 2 receives the optical signal output by the fourth 1×n optical fiber coupler 17;

[0033] The nb-th wide spectrum light source 18(n) provides the nb-th input optical signal I nb , I nb The light enters the nb-th wavelength division multiplexer 12(n) through the first port 12(n)a of the nb-th wavelength division multiplexer 12(n), is coupled by the nb-th wavelength division multiplexer 12(n), enters the second 1×n optical fiber coupler 15 through the third port 12(n)c of the nb-th wavelength division multiplexer 12(n), and is injected into the device under test 41. After exiting the device under test 41, the light enters the first 1×n optical fiber coupler 14. nb The signal enters the nth wavelength division multiplexer 11(n) through the third port 11(n)c of the nth wavelength division multiplexer 11(n), and is separated by the nth wavelength division multiplexer 11(n). nbThe optical signal enters the third 1×n optical fiber coupler 16 from the second port 11 (n) b of the nth wavelength division multiplexer 11 (n), and the optical signal output by the third 1×n optical fiber coupler 16 is received by the optical path modulation and demodulation module 2;

[0034] The optical path modulation and demodulation module 2 includes a first 2×2 optical fiber coupler 24, a second 2×2 optical fiber coupler 25, a fifth 1×n optical fiber coupler 28, a sixth 1×n optical fiber coupler 29, an optical fiber circulator 231, an optical fiber collimating lens 232, an optical path scanner 233, an nc-th wavelength division multiplexer 21(n), an nd-th wavelength division multiplexer 22(n), an na-th differential detector I26(n), an na-th differential detector II27(n), an nb-th differential detector I28(n), and an nb-th differential detector II29(n);

[0035] The first 2×2 fiber coupler 24 is provided with a first input end 24a, a second input end 24b, a first output end 24c and a second output end 24d;

[0036] The second 2×2 fiber coupler 25 is provided with a first input end 25a, a second input end 25b, a first output end 25c and a second output end 25d;

[0037] The nc-th wavelength division multiplexer 21 (n) is provided with a first port 21 (n) a, a second port 21 (n) b and a third port 21 (n) c;

[0038] The nd wavelength division multiplexer 22 (n) is provided with a first port 22 (n) a, a second port 22 (n) b and a third port 22 (n) c;

[0039] The n-th input optical signal output by the fourth 1×n optical fiber coupler 17 enters the second input end 24b of the first 2×2 optical fiber coupler 24; the first output end 24c of the first 2×2 optical fiber coupler 24 outputs a portion of the n-th input optical signal as the n-th reference optical signal to the first input end 25a of the second 2×2 optical fiber coupler 25; the optical fiber circulator 231 receives the other portion of the n-th input optical signal output by the second output end 24d of the first 2×2 optical fiber coupler 24 and transmits the received optical signal to the optical fiber collimating lens 232; the optical signal received by the optical fiber collimating lens 232 is reflected by the optical path scanner 233 and then output by the optical fiber collimating lens 232 as the n-th scanned optical signal to the second input end 25b of the second 2×2 optical fiber coupler 25;

[0040] The nb-th input optical signal output by the third 1×n optical fiber coupler 16 enters the first input end 24a of the first 2×2 optical fiber coupler 24; the first output end 24c of the first 2×2 optical fiber coupler 24 outputs a portion of the nb-th input optical signal as the nb-th reference optical signal to the first input end 25a of the second 2×2 optical fiber coupler 25; the optical fiber circulator 231 receives another portion of the nb-th input optical signal output by the second output end 24d of the first 2×2 optical fiber coupler 24 and transmits the received portion to the optical fiber collimating lens 232; the optical signal received by the optical fiber collimating lens 232 is reflected by the optical path scanner 233 and then output by the optical fiber collimating lens 232 as the nb-th scanned optical signal to the second input end 25b of the second 2×2 optical fiber coupler 25;

[0041] The first output end 25c of the second 2×2 optical fiber coupler 25 is connected to the fifth 1×n optical fiber coupler 28. The ultra-wideband optical signal after interference enters the nc-th wavelength division multiplexer 21(n) through the third port 21(n)c of the nc-th wavelength division multiplexer 21(n). After separation by the nc-th wavelength division multiplexer 21(n), the first port 21(n)a of the nc-th wavelength division multiplexer 21(n) outputs the na-th white light interference signal corresponding to the central wavelength of the na-th broadband light source 13(n). The second port 21(n)b of the nc-th wavelength division multiplexer 21(n) outputs the nb-th white light interference signal corresponding to the central wavelength of the nb-th broadband light source 18(n).

[0042] The second output end 25d of the second 2×2 optical fiber coupler 25 is connected to the sixth 1×n optical fiber coupler 29. The ultra-wideband optical signal after interference enters the nd-th wavelength division multiplexer 22(n) through the third port 22(n)c of the nd-th wavelength division multiplexer 22(n). After separation by the nd-th wavelength division multiplexer 22(n), the first port 22(n)a of the nd-th wavelength division multiplexer 22(n) outputs the nth white light interference signal corresponding to the central wavelength of the na-th broadband light source 13(n). The second port 22(n)b of the nd-th wavelength division multiplexer 22(n) outputs the nb-th white light interference signal corresponding to the central wavelength of the nb-th broadband light source 18(n).

[0043] The nath differential detector I26(n) and the nath differential detector II27(n) perform differential detection on the nath white light interference signal outputted from the first port 21(n)a of the ncth wavelength division multiplexer 21(n) and the first port 22(n)a of the ndth wavelength division multiplexer 22(n) and convert the signal into an electrical signal.

[0044] The nb-th differential detector I28(n) and the nb-th differential detector II29(n) perform differential detection on the nb-th white light interference signal outputted from the second port 21(n)b of the nc-th wavelength division multiplexer 21(n) and the second port 22(n)b of the nd-th wavelength division multiplexer 22(n) and convert the signal into an electrical signal.

[0045] The signal detection and processing module 3 includes a signal acquisition and processing unit 31 and a computer 32;

[0046] The signal acquisition and processing unit 31 simultaneously receives the electrical signals output by the nath differential detector I26 (n), the nath differential detector II27 (n), the nbth differential detector I28 (n), and the nbth differential detector II29 (n) and transmits them to the computer 32;

[0047] The computer 32 calculates the ultra-wideband polarization characteristics of the device under test 41 corresponding to the ultra-wideband light source module 1 using a polarization crosstalk detection and processing algorithm;

[0048] The n is a positive integer and n≧2.

[0049] like Figure 3 As shown, the nath wide spectrum light source 13(n) in the ultra-wide band light source module 1 provides the nath input light signal I na The nb-th wide spectrum light source 18(n) provides the nb-th input optical signal I nb The nath wavelength division multiplexer 11(n) and the nbth wavelength division multiplexer 12(n) combine the input optical signals of different wavelengths provided by the nath broadband light source 13(n) and the nbth broadband light source 18(n) to obtain an ultra-wideband optical signal, which is coupled to the same optical fiber on the optical path through the third 1×n optical fiber coupler 16 and the fourth 1×n optical fiber coupler 17 for transmission. By adjusting the optical path difference of the optical path modulation and demodulation module 2, an ultra-wideband white light interference signal is obtained.

[0050] like Figure 4As shown, after the nc-th wavelength division multiplexer 21(n) in the optical path modulation and demodulation module 2 separates the ultra-wideband white light interference signal, the first port 21(n)a of the nc-th wavelength division multiplexer 21(n) outputs the na-th white light interference signal corresponding to the center wavelength of the na-th wide-spectrum light source 13(n), and the second port 21(n)b of the nc-th wavelength division multiplexer 21(n) outputs the nb-th white light interference signal corresponding to the center wavelength of the nb-th wide-spectrum light source 18(n). After the nd-th wavelength division multiplexer 22(n) in the optical path modulation and demodulation module 2 separates the ultra-wideband white light interference signal, the first port 22(n)a of the nd-th wavelength division multiplexer 22(n) outputs the na-th white light interference signal corresponding to the center wavelength of the na-th wide-spectrum light source 13(n), and the second port 22(n)b of the nd-th wavelength division multiplexer 22(n) outputs the nb-th white light interference signal corresponding to the center wavelength of the nb-th wide-spectrum light source 18(n).

[0051] In this embodiment, the nath wavelength division multiplexer 11(n), the nbth wavelength division multiplexer 12(n), the ncth wavelength division multiplexer 21(n) and the ndth wavelength division multiplexer 22(n) in the ultra-wideband light source module 1 are capable of coupling and separating the optical signal corresponding to the central wavelength of the nath broadband light source 13(n) and the optical signal corresponding to the central wavelength of the nbth broadband light source 18(n).

[0052] In this embodiment, the first 1×n fiber coupler 14, the second 1×n fiber coupler 15, the third 1×n fiber coupler 16, and the fourth 1×n fiber coupler 17 in the ultra-wideband light source module 1 can simultaneously operate at the center wavelengths of the nath broadband light source 13(n) and the nbth broadband light source 18(n).

[0053] In this embodiment, the first 2×2 fiber coupler 24, the second 2×2 fiber coupler 25, the fifth 1×n fiber coupler 28, the sixth 1×n fiber coupler 29, the fiber circulator 231, the fiber collimating lens 232 and the optical path scanner 233 in the optical path modulation and demodulation module 2 can simultaneously operate at the central wavelengths of the nath broadband light source 13(n) and the nbth broadband light source 18(n).

[0054] In this embodiment, the optical wavelength detection range of the nath differential detector I26(n), the nath differential detector II27(n), the nbth differential detector I28(n) and the nbth differential detector II29(n) in the optical path modulation and demodulation module 2 covers the central wavelength of the nath wide-spectrum light source 13(n) and the nbth wide-spectrum light source 18(n).

[0055] Example 2:

[0056] The difference between this embodiment and embodiment 1 is that this embodiment provides a dual-wavelength distributed optical polarization crosstalk simultaneous measurement device, such as Figure 5 As shown, the device includes a dual-wavelength broadband light source module 1, an optical path modulation and demodulation module 2, a signal detection and processing module 3, and a device under test 41, wherein:

[0057] The dual-wavelength broadband light source module 1 includes a first broadband light source 13, a second broadband light source 18, a first wavelength division multiplexer 11, and a second wavelength division multiplexer 12;

[0058] The first wavelength division multiplexer 11 is provided with a first port 11a, a second port 11b, and a third port 11c;

[0059] The second wavelength division multiplexer 12 is provided with a first port 12a, a second port 12b, and a third port 12c;

[0060] The first broadband light source 13 provides a first input optical signal, which enters the first wavelength division multiplexer 11 through the first port 11a of the first wavelength division multiplexer 11, is coupled by the first wavelength division multiplexer 11, and is injected into the device under test 41 through the third port 11c of the first wavelength division multiplexer 11. After being emitted from the device under test 41, the first input optical signal enters the second wavelength division multiplexer 12 through the third port 12c of the second wavelength division multiplexer 12. After being separated by the second wavelength division multiplexer 12, the first input optical signal enters the optical path modulation and demodulation module 2 through the second port 12b of the second wavelength division multiplexer 12, and the optical path modulation and demodulation module 2 receives the first input optical signal output by the second wavelength division multiplexer 12.

[0061] The second broadband light source 18 provides a second input optical signal, which enters the second wavelength division multiplexer 12 through the first port 12a of the second wavelength division multiplexer 12, is coupled by the second wavelength division multiplexer 12, and is injected into the device under test 41 through the third port 12c of the second wavelength division multiplexer 12. After being emitted from the device under test 41, the second input optical signal enters the first wavelength division multiplexer 11 through the third port 11c of the first wavelength division multiplexer 11. After being separated by the first wavelength division multiplexer 11, the second input optical signal enters the optical path modulation and demodulation module 2 through the second port 11b of the first wavelength division multiplexer 11, and the optical path modulation and demodulation module 2 receives the second input optical signal output by the first wavelength division multiplexer 11.

[0062] The optical path modulation and demodulation module 2 includes a first 2×2 optical fiber coupler 24, a second 2×2 optical fiber coupler 25, a third wavelength division multiplexer 21, a fourth wavelength division multiplexer 22, a first differential detector I261, a first differential detector II271, a second differential detector I281, a second differential detector II291, a fiber circulator 231, a fiber collimating lens 232, and an optical path scanner 233;

[0063] The first 2×2 fiber coupler 24 is provided with a first input end 24a, a second input end 24b, a first output end 24c, and a second output end 24d;

[0064] The second 2×2 fiber coupler 25 is provided with a first input end 25a, a second input end 25b, a first output end 25c, and a second output end 25d;

[0065] The third wavelength division multiplexer 21 is provided with a first port 21a, a second port 21b, and a third port 21c, and the fourth wavelength division multiplexer 22 is provided with a first port 22a, a second port 22b, and a third port 22c;

[0066] The first input optical signal output by the second wavelength division multiplexer 12 enters the second input end 24b of the first 2×2 optical fiber coupler 24; the first output end 24c of the first 2×2 optical fiber coupler 24 outputs a portion of the first input optical signal as a first reference optical signal to the first input end 25a of the second 2×2 optical fiber coupler 25; the optical fiber circulator 231 receives another portion of the first input optical signal output by the second output end 24d of the first 2×2 optical fiber coupler 24 and transmits the received optical signal to the optical fiber collimating lens 232; the optical signal received by the optical fiber collimating lens 232 is reflected by the optical path scanner 233 and then output by the optical fiber collimating lens 232 as a first scanned optical signal to the second input end 25b of the second 2×2 optical fiber coupler 25;

[0067] The second input optical signal output by the first wavelength division multiplexer 11 enters the first input end 24a of the first 2×2 optical fiber coupler 24; the first output end 24c of the first 2×2 optical fiber coupler 24 outputs a portion of the second input optical signal as a second reference optical signal to the first input end 25a of the second 2×2 optical fiber coupler 25; the optical fiber circulator 231 receives the other portion of the second input optical signal output by the second output end 24d of the first 2×2 optical fiber coupler 24 and transmits the received optical signal to the optical fiber collimating lens 232; the optical signal received by the optical fiber collimating lens 232 is reflected by the optical path scanner 233 and then output by the optical fiber collimating lens 232 as a second scanned optical signal to the second input end 25b of the second 2×2 optical fiber coupler 25;

[0068] The first output end 25c of the second 2×2 fiber coupler 25 is connected to the third wavelength division multiplexer 21. The ultra-wideband optical signal after interference enters the third wavelength division multiplexer 21 through the third port 21c of the third wavelength division multiplexer 21. After separation by the third wavelength division multiplexer 21, the first port 21a of the third wavelength division multiplexer 21 outputs a first white light interference signal corresponding to the center wavelength of the first broadband light source 13, and the second port 21b of the third wavelength division multiplexer 21 outputs a second white light interference signal corresponding to the center wavelength of the second broadband light source 18.

[0069] The second output end 25d of the second 2×2 fiber coupler 25 is connected to the fourth wavelength division multiplexer 22. The interfered dual-band optical signal enters the fourth wavelength division multiplexer 22 through the third port 22c of the fourth wavelength division multiplexer 22. After separation by the fourth wavelength division multiplexer 22, the first port 22a of the fourth wavelength division multiplexer 22 outputs a first white light interference signal corresponding to the center wavelength of the first broadband light source 13. The second port 22b of the fourth wavelength division multiplexer 22 outputs a second white light interference signal corresponding to the center wavelength of the second broadband light source 18.

[0070] The first differential detector I261 and the first differential detector II271 perform differential detection on the first white light interference signal outputted by the first port 21a of the third wavelength division multiplexer 21 and the first port 22a of the fourth wavelength division multiplexer 22 and convert the signal into an electrical signal.

[0071] The second differential detector I281 and the second differential detector II291 perform differential detection on the second white light interference signal outputted by the second port 21b of the third wavelength division multiplexer 21 and the second port 22b of the fourth wavelength division multiplexer 22 and convert the signal into an electrical signal;

[0072] The signal detection and processing module 3 includes a signal acquisition and processing unit 31 and a computer 32;

[0073] The signal acquisition and processing unit 31 simultaneously receives the electrical signals output by the first differential detector I261, the first differential detector II271, the second differential detector I281, and the second differential detector II291 and transmits them to the computer 32;

[0074] The computer 32 calculates the ultra-wideband polarization characteristics of the device under test 41 corresponding to the ultra-wideband light source module 1 using a polarization crosstalk detection and processing algorithm.

[0075] In this embodiment, the first wavelength division multiplexer 11, the second wavelength division multiplexer 12, the third wavelength division multiplexer 21 and the fourth wavelength division multiplexer 22 can couple and separate the optical signal corresponding to the center wavelength of the first broadband light source 13 and the optical signal corresponding to the center wavelength of the second broadband light source 18.

[0076] In this embodiment, the first 2×2 fiber coupler 24 , the second 2×2 fiber coupler 25 , the fiber circulator 231 , the fiber collimating lens 232 and the optical path scanner 233 can simultaneously operate at the central wavelengths of the first broadband light source 13 and the second broadband light source 18 .

[0077] In this embodiment, the optical wavelength detection ranges of the first differential detector I261 , the first differential detector II271 , the second differential detector I281 , and the second differential detector II291 cover the center wavelengths of the first broadband light source 13 and the second broadband light source 18 .

[0078] In this embodiment, the design dimensions of each mechanical structure and the parameters of each component are selected as follows:

[0079] The central wavelength of the first broadband light source 13 is 1550nm, the half-spectrum width is greater than 45nm, the fiber output power is greater than 3mW, the amplitude of the ripple self-coherence peak of the light source spectrum is about -60dB, and the optical path range of the ripple self-coherence peak is about 4-7mm;

[0080] The central wavelength of the second broad spectrum light source 18 is 1310 nm, the half-spectrum width is greater than 45 nm, the fiber output power is greater than 3 mW, the amplitude of the ripple self-coherence peak of the light source spectrum is about -60 dB, and the optical path range of the ripple self-coherence peak is about 4 to 7 mm;

[0081] The operating wavelength of the device under test 41 is 1550nm & 1310nm;

[0082] The first wavelength division multiplexer 11, the second wavelength division multiplexer 12, the third wavelength division multiplexer 21 and the fourth wavelength division multiplexer 22 all use an operating wavelength of 1550nm (transmission) & 1310nm (reflection), a half-band width greater than 40nm, a transmission (1550nm) insertion loss ≤0.8dB, an isolation ≥30dB, a reflection (1310nm) insertion loss ≤0.6dB, an isolation ≥15dB, and are capable of coupling and separating 1550nm optical signals and 1310nm optical signals;

[0083] The first 2×2 fiber coupler 24 and the second 2×2 fiber coupler 25 are both single-mode couplers with an operating wavelength of 1550 nm and 1310 nm, an insertion loss of ≤0.5 dB, and a splitting ratio of 50:50.

[0084] The optical fiber circulator 231 uses a three-port circulator with an operating wavelength of 1550nm and 1310nm. Its working mode is that the light injected into the circulator port 1 will be output from the circulator port 2, and the light injected into the circulator port 2 will be output from the circulator port 3. The insertion loss between each two ports is ≤1dB, and the isolation is ≥40dB.

[0085] The working wavelength of the optical fiber collimating lens 232 is 1550nm & 1310nm;

[0086] The optical path scanning range of the optical path scanner 233 is 100 mm (the scanning range can be adjusted according to the measurement length of the device under test 41);

[0087] The optical wavelength detection range of the first differential detector I261, the first differential detector II271, the second differential detector I281 and the second differential detector II291 is 1200-1700 nm, and the photoelectric conversion responsivity is greater than 0.8;

[0088] The first differential detector I261, the first differential detector II271, the second differential detector I281 and the second differential detector II291 are implemented using a basic PBC circuit board;

[0089] The signal acquisition and processing unit 31 uses a general 8-bit A / D conversion circuit;

[0090] The wires used by the signal detection and processing module 3 are all ordinary copper core wires.

[0091] In this embodiment, the dual-wavelength distributed optical polarization crosstalk simultaneous measurement device operates as follows:

[0092] The first broadband light source 13 provides a 1550nm input optical signal. The 1550nm input optical signal enters the first wavelength division multiplexer 11 through the first port 11a of the first wavelength division multiplexer 11. After being coupled by the first wavelength division multiplexer 11, the signal enters the device under test 41 through the third port 11c of the first wavelength division multiplexer 11. After being emitted from the device under test 41, the signal enters the second wavelength division multiplexer 12 through the third port 12c of the second wavelength division multiplexer 12. After being separated by the second wavelength division multiplexer 12, the signal enters the first 2×2 optical fiber coupler 24 through the second port 12b of the second wavelength division multiplexer 12. The optical path modulation and demodulation module 2 receives the 1550nm input optical signal.

[0093] The second broadband light source 18 provides a 1310 nm input optical signal. The 1310 nm input optical signal enters the second wavelength division multiplexer 12 through the first port 12 a of the second wavelength division multiplexer 12. After being coupled by the second wavelength division multiplexer 12, the signal enters the device under test 41 through the third port 12 c of the second wavelength division multiplexer 12. After being emitted from the device under test 41, the signal enters the first wavelength division multiplexer 11 through the third port 11 c of the first wavelength division multiplexer 11. After being separated by the first wavelength division multiplexer 11, the signal enters the first 2×2 optical fiber coupler 24 through the second port 11 b of the first wavelength division multiplexer 11. The optical path modulation and demodulation module 2 receives the 1310 nm input optical signal.

[0094] The 1550 nm input optical signal outputted from the second port 12 b of the second wavelength division multiplexer 12 enters the second input end 24 b of the first 2×2 optical fiber coupler 24; the first output end 24 c of the first 2×2 optical fiber coupler 24 outputs 50% of the 1550 nm input optical signal as a reference optical signal having a central wavelength of 1550 nm and outputs the signal to the first input end 25 a of the second 2×2 optical fiber coupler 25; the optical fiber circulator 231 receives the other 50% of the 1550 nm input optical signal outputted from the second output end 24 d of the first 2×2 optical fiber coupler 24 and transmits the signal to the optical fiber collimating lens 232; the optical signal received by the optical fiber collimating lens 232 is reflected by the optical path scanner 233 and then outputted from the optical fiber collimating lens 232 as a scanned optical signal having a central wavelength of 1550 nm and output to the second input end 25 b of the second 2×2 optical fiber coupler 25;

[0095] The 1310 nm input optical signal outputted from the second port 11 b of the first wavelength division multiplexer 11 enters the first input end 24 a of the first 2×2 optical fiber coupler 24; the first output end 24 c of the first 2×2 optical fiber coupler 24 outputs 50% of the 1310 nm input optical signal as a reference optical signal having a central wavelength of 1310 nm and outputs the signal to the first input end 25 a of the second 2×2 optical fiber coupler 25; the optical fiber circulator 231 receives the other 50% of the 1310 nm input optical signal outputted from the second output end 24 d of the first 2×2 optical fiber coupler 24 and transmits the signal to the optical fiber collimating lens 232; the optical signal received by the optical fiber collimating lens 232 is reflected by the optical path scanner 233 and then outputted from the optical fiber collimating lens 232 as a scanned optical signal having a central wavelength of 1310 nm and output to the second input end 25 b of the second 2×2 optical fiber coupler 25;

[0096] The first output end 25c of the second 2×2 fiber coupler 25 is connected to the third wavelength division multiplexer 21. The interfered dual-band optical signal enters the third wavelength division multiplexer 21 through the third port 21c of the third wavelength division multiplexer 21. After separation by the third wavelength division multiplexer 21, the first port 21a of the third wavelength division multiplexer 21 outputs a 1550nm white light interference signal corresponding to the center wavelength of the first broadband light source 13, and the second port 21b of the third wavelength division multiplexer 21 outputs a 1310nm white light interference signal corresponding to the center wavelength of the second broadband light source 18.

[0097] The second output end 25d of the second 2×2 fiber coupler 25 is connected to the fourth wavelength division multiplexer 22. The interfered dual-band optical signal enters the fourth wavelength division multiplexer 22 through the third port 22c of the fourth wavelength division multiplexer 22. After separation by the fourth wavelength division multiplexer 22, the first port 22a of the fourth wavelength division multiplexer 22 outputs a 1550nm white light interference signal corresponding to the center wavelength of the first broadband light source 13. The second port 22b of the fourth wavelength division multiplexer 22 outputs a 1310nm white light interference signal corresponding to the center wavelength of the second broadband light source 18.

[0098] The first differential detector I261 and the first differential detector II271 perform differential detection on the 1550nm white light interference signal outputted from the first port 21a of the third wavelength division multiplexer 21 and the first port 22a of the fourth wavelength division multiplexer 22 and convert the signal into an electrical signal;

[0099] The second differential detector I281 and the second differential detector II291 perform differential detection on the 1310 nm white light interference signal outputted from the second port 21 b of the third wavelength division multiplexer 21 and the second port 22 b of the fourth wavelength division multiplexer 22 and convert the signal into an electrical signal;

[0100] The signal acquisition and processing unit 31 receives the electrical signal and transmits it to the computer 32 via the data transmission line. The computer 32 detects the 1550nm white light interference signal and the 1310nm white light interference signal converted into electrical signals using the polarization crosstalk detection and processing algorithm, and simultaneously processes the polarization coupling coefficient ρ when the working wavelength is 1550nm based on formula (1): 1550 And the polarization coupling coefficient ρ when the operating wavelength is 1310nm 1310 Finally, the polarization characteristics of the device under test 41 are measured simultaneously at dual working wavelengths of 1550 nm and 1310 nm.

Claims

1. A device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range, characterized in that The measuring device includes an ultra-wideband light source module, an optical path modulation and demodulation module, a signal detection and processing module, and a device to be measured, wherein: The ultra-wideband light source module provides input optical signals with different central wavelengths, which are injected from both ends of the device under test and emitted from the device under test. After passing through the ultra-wideband light source module, they are received by the optical path modulation and demodulation module. Based on the principle of white light interferometry, by adjusting the optical path difference of the optical path modulation and demodulation modules, ultra-wideband white light interference signals are simultaneously obtained and converted into electrical signals. The signal detection and processing module calculates the ultra-wideband polarization characteristics of the device under test corresponding to the ultra-wideband light source module based on the electrical signals.

2. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 1, characterized in that The ultra-wideband light source module includes a nath wide-spectrum light source, an nbth wide-spectrum light source, a nath wavelength division multiplexer, an nbth wavelength division multiplexer, a first 1×n optical fiber coupler, a second 1×n optical fiber coupler, a third 1×n optical fiber coupler, and a fourth 1×n optical fiber coupler; The nath wavelength division multiplexer is provided with a first port, a second port and a third port; The nb-th wavelength division multiplexer is provided with a first port, a second port and a third port; The nath wide spectrum light source provides the nath input light signal , It enters the nth wavelength division multiplexer through the first port of the nth wavelength division multiplexer, is coupled by the nth wavelength division multiplexer, enters the first 1×n optical fiber coupler through the third port of the nth wavelength division multiplexer, and is injected into the device under test. After exiting the device under test, it enters the second 1×n optical fiber coupler. It enters the nbth wavelength division multiplexer through the third port of the nbth wavelength division multiplexer, and after being separated by the nbth wavelength division multiplexer, The optical signal enters the fourth 1×n optical fiber coupler from the second port of the nb-th wavelength division multiplexer, and the optical path modulation and demodulation module receives the optical signal output by the fourth 1×n optical fiber coupler; The nbth wide spectrum light source provides the nbth input optical signal , The light enters the nbth wavelength division multiplexer through the first port of the nbth wavelength division multiplexer, is coupled by the nbth wavelength division multiplexer, enters the second 1×n optical fiber coupler through the third port of the nbth wavelength division multiplexer, and is injected into the device under test. After exiting the device under test, it enters the first 1×n optical fiber coupler. It enters the nth wavelength division multiplexer through the third port of the nth wavelength division multiplexer, and after being separated by the nth wavelength division multiplexer, The optical signal enters the third 1×n optical fiber coupler from the second port of the nth wavelength division multiplexer, and the optical path modulation and demodulation module receives the optical signal output by the third 1×n optical fiber coupler; The optical path modulation and demodulation module includes a first 2×2 optical fiber coupler, a second 2×2 optical fiber coupler, a fifth 1×n optical fiber coupler, a sixth 1×n optical fiber coupler, an optical fiber circulator, an optical fiber collimating lens, an optical path scanner, an nc-th wavelength division multiplexer, an nd-th wavelength division multiplexer, a na-th differential detector, and a na-th differential detector. , nbth differential detector and nbth differential detector ; The first 2×2 optical fiber coupler is provided with a first input end, a second input end, a first output end and a second output end; The second 2×2 optical fiber coupler is provided with a first input end, a second input end, a first output end, and a second output end; The nc-th wavelength division multiplexer is provided with a first port, a second port and a third port; The nd wavelength division multiplexer is provided with a first port, a second port and a third port; The n-th input optical signal output by the fourth 1×n optical fiber coupler enters the second input end of the first 2×2 optical fiber coupler; the first output end of the first 2×2 optical fiber coupler outputs a portion of the n-th input optical signal as the n-th reference optical signal to the first input end of the second 2×2 optical fiber coupler; the optical fiber circulator receives another portion of the n-th input optical signal output by the second output end of the first 2×2 optical fiber coupler and transmits the received portion to the optical fiber collimating lens; the optical signal received by the optical fiber collimating lens is reflected by the optical path scanner and then output through the optical fiber collimating lens as the n-th scanned optical signal to the second input end of the second 2×2 optical fiber coupler; The nb-th input optical signal output by the third 1×n optical fiber coupler enters the first input end of the first 2×2 optical fiber coupler; the first output end of the first 2×2 optical fiber coupler outputs a portion of the nb-th input optical signal as the nb-th reference optical signal to the first input end of the second 2×2 optical fiber coupler; the optical fiber circulator receives another portion of the nb-th input optical signal output by the second output end of the first 2×2 optical fiber coupler and transmits the received portion to the optical fiber collimating lens; the optical signal received by the optical fiber collimating lens is reflected by the optical path scanner and then output through the optical fiber collimating lens as the nb-th scanned optical signal to the second input end of the second 2×2 optical fiber coupler; The first output end of the second 2×2 optical fiber coupler is connected to the fifth 1×n optical fiber coupler, and the ultra-wideband optical signal after interference enters the nc-th wavelength division multiplexer through the third port of the nc-th wavelength division multiplexer. After separation by the nc-th wavelength division multiplexer, the na-th white light interference signal corresponding to the central wavelength of the na-th wide-spectrum light source is output from the first port of the nc-th wavelength division multiplexer, and the nb-th white light interference signal corresponding to the central wavelength of the nb-th wide-spectrum light source is output from the second port of the nc-th wavelength division multiplexer. The second output end of the second 2×2 optical fiber coupler is connected to the sixth 1×n optical fiber coupler, and the ultra-wideband optical signal after interference enters the ndth wavelength division multiplexer through the third port of the ndth wavelength division multiplexer. After separation by the ndth wavelength division multiplexer, the nath white light interference signal corresponding to the center wavelength of the nath broadband light source is output through the first port of the ndth wavelength division multiplexer, and the nbth white light interference signal corresponding to the center wavelength of the nbth broadband light source is output through the second port of the ndth wavelength division multiplexer. The na differential detector , nath differential detector Performing differential detection on the nath white light interference signal outputted from the first port of the ncth wavelength division multiplexer and the first port of the ndth wavelength division multiplexer and converting the signal into an electrical signal; The nb differential detector , nbth differential detector performing differential detection on the nbth white light interference signal outputted from the second port of the ncth wavelength division multiplexer and the second port of the ndth wavelength division multiplexer and converting the signal into an electrical signal; The signal detection and processing module includes a signal acquisition and processing unit and a computer; The signal acquisition and processing unit simultaneously receives the nath differential detector , nath differential detector, nbth differential detector, nbth differential detector The output electrical signal is transmitted to the computer; The computer calculates the ultra-wideband polarization characteristics of the device under test corresponding to the ultra-wideband light source module using a polarization crosstalk detection and processing algorithm; The n is a positive integer and n≧2.

3. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 2, characterized in that The nath, nbth, ncth and ndth wavelength division multiplexers can couple and separate the optical signal corresponding to the central wavelength of the nath wide spectrum light source and the optical signal corresponding to the central wavelength of the nbth wide spectrum light source.

4. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 2, characterized in that The first 1×n optical fiber coupler, the second 1×n optical fiber coupler, the third 1×n optical fiber coupler, and the fourth 1×n optical fiber coupler can simultaneously operate at the central wavelengths of the nath broadband light source and the nbth broadband light source.

5. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 2, characterized in that The first 2×2 fiber coupler, the second 2×2 fiber coupler, the fifth 1×n fiber coupler, the sixth 1×n fiber coupler, the fiber circulator, the fiber collimating lens and the optical path scanner can simultaneously operate at the central wavelengths of the nath broadband light source and the nbth broadband light source.

6. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 2, characterized in that The na differential detector , nath differential detector , nbth differential detector The optical wavelength detection range of the nb-th differential detector covers the central wavelengths of the na-th broadband light source and the nb-th broadband light source.

7. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 1, characterized in that The ultra-wideband light source module includes a first wide-spectrum light source, a second wide-spectrum light source, a first wavelength division multiplexer, and a second wavelength division multiplexer; The first wavelength division multiplexer is provided with a first port, a second port, and a third port; The second wavelength division multiplexer is provided with a first port, a second port, and a third port; The first broadband light source provides a first input optical signal, the first input optical signal enters the first wavelength division multiplexer through the first port of the first wavelength division multiplexer, is coupled by the first wavelength division multiplexer, is injected into the device under test through the third port of the first wavelength division multiplexer, is emitted from the device under test, enters the second wavelength division multiplexer through the third port of the second wavelength division multiplexer, is separated by the second wavelength division multiplexer, and then enters the optical path modulation and demodulation module through the second port of the second wavelength division multiplexer, and the optical path modulation and demodulation module receives the first input optical signal output by the second wavelength division multiplexer; The second broadband light source provides a second input optical signal, the second input optical signal enters the second wavelength division multiplexer through the first port of the second wavelength division multiplexer, is coupled by the second wavelength division multiplexer, is injected into the device under test through the third port of the second wavelength division multiplexer, is emitted from the device under test, enters the first wavelength division multiplexer through the third port of the first wavelength division multiplexer, is separated by the first wavelength division multiplexer, and then enters the optical path modulation and demodulation module through the second port of the first wavelength division multiplexer, and the optical path modulation and demodulation module receives the second input optical signal output by the first wavelength division multiplexer; The optical path modulation and demodulation module includes a first 2×2 optical fiber coupler, a second 2×2 optical fiber coupler, a third wavelength division multiplexer, a fourth wavelength division multiplexer, a first differential detector , first differential detector , the second differential detector , the second differential detector , fiber circulator, fiber collimating lens, optical path scanner; The first 2×2 optical fiber coupler is provided with a first input end, a second input end, a first output end, and a second output end; The second 2×2 optical fiber coupler is provided with a first input end, a second input end, a first output end, and a second output end; The third wavelength division multiplexer is provided with a first port, a second port, and a third port; The fourth wavelength division multiplexer is provided with a first port, a second port, and a third port; The first input optical signal output by the second wavelength division multiplexer enters the second input end of the first 2×2 optical fiber coupler; the first output end of the first 2×2 optical fiber coupler outputs a portion of the first input optical signal as a first reference optical signal to the first input end of the second 2×2 optical fiber coupler; the optical fiber circulator receives another portion of the first input optical signal output by the second output end of the first 2×2 optical fiber coupler and transmits the received optical signal to the optical fiber collimating lens; the optical signal received by the optical fiber collimating lens is reflected by the optical path scanner and then output through the optical fiber collimating lens as a first scanned optical signal to the second input end of the second 2×2 optical fiber coupler; The second input optical signal output by the first wavelength division multiplexer enters the first input end of the first 2×2 optical fiber coupler; the first output end of the first 2×2 optical fiber coupler outputs a portion of the second input optical signal as a second reference optical signal to the first input end of the second 2×2 optical fiber coupler; the optical fiber circulator receives another portion of the second input optical signal output by the second output end of the first 2×2 optical fiber coupler and transmits the received optical signal to the optical fiber collimating lens; the optical signal received by the optical fiber collimating lens is reflected by the optical path scanner and then output through the optical fiber collimating lens as a second scanned optical signal to the second input end of the second 2×2 optical fiber coupler; The first output end of the second 2×2 optical fiber coupler is connected to a third wavelength division multiplexer, and the ultra-wideband optical signal after interference enters the third wavelength division multiplexer through the third port of the third wavelength division multiplexer. After separation by the third wavelength division multiplexer, the first port of the third wavelength division multiplexer outputs a first white light interference signal corresponding to the center wavelength of the first broadband light source, and the second port of the third wavelength division multiplexer outputs a second white light interference signal corresponding to the center wavelength of the second broadband light source. The second output end of the second 2×2 optical fiber coupler is connected to a fourth wavelength division multiplexer, and the interfered dual-band optical signal enters the fourth wavelength division multiplexer through the third port of the fourth wavelength division multiplexer. After separation by the fourth wavelength division multiplexer, the first port of the fourth wavelength division multiplexer outputs a first white light interference signal corresponding to the center wavelength of the first broadband light source, and the second port of the fourth wavelength division multiplexer outputs a second white light interference signal corresponding to the center wavelength of the second broadband light source. The first differential detector , first differential detector performing differential detection on the first white light interference signal outputted from the first port of the third wavelength division multiplexer and the first port of the fourth wavelength division multiplexer and converting the signal into an electrical signal; The second differential detector, the second differential detector performing differential detection on the second white light interference signal outputted by the second port of the third wavelength division multiplexer and the second port of the fourth wavelength division multiplexer and converting the signal into an electrical signal; The signal detection and processing module includes a signal acquisition and processing unit and a computer; The signal acquisition and processing unit simultaneously receives the first differential detector , first differential detector , the second differential detector , the electrical signal output by the second differential detector is transmitted to a computer; The computer calculates the ultra-wideband polarization characteristics of the device under test corresponding to the ultra-wideband light source module using a polarization crosstalk detection and processing algorithm.

8. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 7, characterized in that The first wavelength division multiplexer, the second wavelength division multiplexer, the third wavelength division multiplexer and the fourth wavelength division multiplexer can couple and separate the optical signal corresponding to the central wavelength of the first broadband light source and the optical signal corresponding to the central wavelength of the second broadband light source.

9. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 7, characterized in that The first 2×2 fiber coupler, the second 2×2 fiber coupler, the fiber circulator, the fiber collimating lens and the optical path scanner can simultaneously operate at the central wavelengths of the first broadband light source and the second broadband light source.

10. The device for measuring distributed optical polarization crosstalk over an ultra-wide spectral range according to claim 7, characterized in that The first differential detector , first differential detector , the second differential detector and the second differential detector The light wavelength detection range covers the central wavelengths of the first broadband light source and the second broadband light source.

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