Fiber sensitive loop loss test system and method based on Lyot depolarizer

Abstract

The present invention discloses a fiber sensitive ring loss test system and method based on a Lyot depolarizer. The system comprises: a coupler module comprising an input end, two output ends and a composite input and output end, the input end of the coupler module is connected to a light source module to receive an optical signal output by the light source module, one output end of the coupler module is connected to an input end of a Lyot depolarizer module, the other output end of the coupler module is a waste end, the composite input and output end of the coupler module is connected to a second optical power measurement module through a second adapter module to receive an optical signal to be measured returned from an optical path; the pigtail of the first optical power measurement module is connected to the output end of the Lyot depolarizer module through a first adapter module and a connector module; the output end of the Lyot depolarizer module is also connected to the fiber sensitive ring to be measured. The present invention improves the accuracy and consistency of the fiber sensitive ring loss test.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber sensitive ring performance testing, in particular to an optical fiber sensitive ring loss testing system and method based on a Lyot depolarizer. Background Art

[0002] Fiber optic gyroscope is an instrument that can accurately determine the position of a moving object. It is an inertial navigation instrument widely used in modern aviation, navigation, and aerospace industries. Its development is of great significance to the development of industry and other high technologies. The fiber optic sensitive ring is an important component of the fiber optic gyroscope. Since the loss performance of the fiber optic sensitive ring is an important factor affecting the fiber optic gyroscope, strict requirements are placed on the loss test instrument of the fiber optic sensitive ring.

[0003] In the prior art, the loss test system of the optical fiber sensitive loop generally directly connects the coupler module to the optical fiber sensitive loop to be tested to perform the loss test. The limitations of the prior art are:

[0004] 1. Relying on different testers to perform manual operations, there are many uncontrollable factors. In addition, when the pigtail of the optical fiber sensitive ring is fused with the test system, the melting point and the pigtail force cannot guarantee the consistency of the loss test results, which increases the test cost;

[0005] 2. The influence of the non-reciprocal phase difference introduced by the coupling, birefringence and environmental interference inside the optical fiber sensitive ring on the output light intensity will affect the accuracy of the optical fiber sensitive ring loss test results; Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a fiber optic sensitive loop loss testing system and method based on a Lyot depolarizer, which can ensure the reliability of the fiber optic sensitive loop during the loss testing process.

[0007] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0008] The optical fiber sensitive ring loss test system based on Lyot depolarizer of the present invention comprises: a light source module, a coupler module, a first optical power measurement module, a second optical power measurement module, a first adapter module, a second adapter module, a Lyot depolarizer module and a connector module;

[0009] The light source module is connected to the coupler module to input the low-polarization light signal into the coupler module;

[0010] The coupler module comprises an input end, two output ends and a composite input and output end, the input end of the coupler module is connected to the light source module to receive the optical signal output by the light source module, one output end of the coupler module is connected to the input end of the Lyot depolarizer module, the other output end of the coupler module is a waste end, the composite input and output end of the coupler module is connected to the second optical power measurement module through the second adapter module, and the second optical power measurement module receives the optical signal to be measured returned from the composite input and output end of the coupler module;

[0011] The first optical power measurement module is connected to the output end of the Lyot depolarizer module through the first adapter module and the connector module;

[0012] The output end of the Lyot depolarizer module is also connected to the optical fiber sensitive ring to be tested through a connector module.

[0013] A further improvement of the present invention is that the light source module includes an SLD light source and an SLD light source driver, the SLD light source outputs a light signal with stable power to the coupler module, and the SLD driver performs power driving and temperature control on the SLD light source.

[0014] A further improvement of the present invention is that the coupler module includes a 2×2 optical fiber coupler to achieve optical power distribution of the original optical signal at different output ends.

[0015] A further improvement of the present invention is that the splitting ratio of the optical fiber coupler is 1:1.

[0016] A further improvement of the present invention is that: the first optical power measurement module is an input optical power measurement module, which is used to measure the optical power input to the sensitive ring of the optical fiber to be measured.

[0017] A further improvement of the present invention is that the second optical power measurement module is an output optical power measurement module, which is used to perform polarization-maintaining fusion splicing on the pigtail at the output end of the Lyot depolarizer module and the pigtail of the optical fiber sensitive ring to be tested, and then measure the optical power of the input light after passing through the optical fiber sensitive ring to be tested and returning to the coupler module.

[0018] A further improvement of the present invention is that the Lyot depolarizer module is formed by fusing polarization-maintaining optical fibers with fixed length ratios at both ends at a 45° fusing angle, so that the optical signal passing through the coupler is transmitted into the optical fiber sensitive ring in a completely non-polarized form.

[0019] The optical fiber sensitive ring loss test method based on Lyot depolarizer of the present invention comprises the following operations:

[0020] Step S1, connecting the first optical power measurement module to the polarization-maintaining optical fiber at the output end of the Lyot depolarizer module through the first adapter module and the connector module, turning on the system power supply, and after the optical fiber sensitive ring loss test system based on the Lyot depolarizer is stably powered, turning on the power supply of the first optical power measurement module, setting the working wavelength of the polarization-maintaining optical fiber, and recording the optical power P1 of the first optical power measurement module at this time, where P1 is the optical power value input to the optical fiber sensitive ring to be tested;

[0021] Step S2, disconnecting the first adapter module from the connector module, connecting the polarization-maintaining optical fiber at the output end of the Lyot depolarizer module to the single end of the optical fiber sensitive ring to be tested through the connector module, and recording the loss L1 of the Lyot depolarizer module;

[0022] Step S3, connecting the second optical power measurement module to the polarization-maintaining optical fiber at the composite input and output end of the coupler module through the second adapter module, turning on the power of the second optical power measurement module, setting the working wavelength of the polarization-maintaining optical fiber, and recording the optical power, which is the optical power P2 at this time;

[0023] Step S4, recording the factory loss value L2 of the coupler module;

[0024] Step S5, based on the loss calculation expression E L =10*lg(P1 / P2)-(L1+L2), and the loss value E of the optical fiber sensitive ring to be tested is obtained. L , if the loss value E L If it does not meet the preset requirements, disconnect the welding point in step S2 and weld it again, and then repeat the operation steps in steps S2-S5 to calculate the loss value E. L , if the loss value E is measured three times in a row L If all of them are unqualified, the optical fiber sensitive ring to be tested is determined to be unqualified, the single-ended polarization-maintaining optical fiber pigtail of the current optical fiber sensitive ring is removed from the connector module, and the single-ended polarization-maintaining optical fiber pigtail of the next optical fiber sensitive ring to be tested is inserted for the next round of testing.

[0025] A further improvement of the present invention is that the operating wavelength of the polarization-maintaining optical fiber set in step S1 is consistent with the operating wavelength of the polarization-maintaining optical fiber set in step S3.

[0026] The beneficial effects of the present invention are as follows: the present invention eliminates the influence of most uncontrollable factors on the loss test results through the Lyot depolarizer module, reduces the loss test deviation caused by single operations of different personnel and multiple operations of the same person, ensures the stability and consistency of the loss test results, and reduces the test cost. At the same time, the Lyot depolarizer module reduces the influence of the non-reciprocal phase difference introduced by the coupling, birefringence and environmental interference inside the optical fiber sensitive ring on the output light intensity, ensuring the accuracy and reliability of the loss test results of the optical fiber sensitive ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of a fiber sensitive ring loss test system based on a Lyot depolarizer in an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of a fiber sensitive loop loss test system based on a Lyot depolarizer in an embodiment of the present invention performing a loss test on a fiber sensitive loop;

[0029] Figure 3 is a schematic structural diagram of a Lyot depolarizer module in an embodiment of the present invention;

[0030] Among them: 1-light source module, 2-coupler module, 3-Lyot depolarizer module, 4-first optical power measurement module, 5-second optical power measurement module, 6-second adapter module, 7-connector module, 8-first adapter module. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 1 As shown, the optical fiber sensitive ring loss test system based on Lyot depolarizer of this embodiment includes: a light source module 1, a coupler module 2, a Lyot depolarizer module 3, a first optical power measurement module 4, a second optical power measurement module 5, a second adapter module 6, a connector module 7 and a first adapter module 8.

[0033] The light source module 1 is connected to the coupler module 2, and the low polarization light signal is input to the coupler module 2. The light source module 1 includes an SLD light source and an SLD driver. The SLD light source outputs a light signal with stable power to the coupler module 2. The SLD driver performs power drive and temperature control on the SLD light source. The light source module 1 in this embodiment emits a stable light signal with a wavelength of 1310nm.

[0034] The coupler module 2 includes an input terminal, two output terminals and a composite input and output terminal. Figure 1As shown, the a end of the coupler module 2 is the input end, which is connected to the optical fiber at the output end of the light source module 1 through a fusion bond. The b end of the coupler module 2 is a composite input and output end, and the b end is a bare optical fiber, which can be directly mechanically plugged into and fixed at the signal input end of the second optical power measurement module 5 through the second adapter module 6. The c end of the coupler module 2 is the output end, which is connected to the polarization-maintaining optical fiber at the input end of the Lyot depolarizer module 3 through a fusion bond. The d end of the coupler module 2 is the waste end of the bare optical fiber, which only plays a role in splitting in the actual optical path. The coupler module 2 of this embodiment realizes the distribution of optical signal power among different optical fibers. It is a 2×2 optical fiber coupler with a splitting ratio of 1:1, and can distribute part of the returned optical signal to the second optical power measurement module 5.

[0035] The first optical power measurement module 4 in this embodiment is an input optical power measurement module, which is used to measure the optical power input to the optical fiber sensitive ring to be tested. The second optical power measurement module 5 is an output optical power measurement module, which is used to perform polarization-maintaining fusion splicing of the pigtail at the output end of the Lyot depolarizer module and the pigtail of the optical fiber sensitive ring to be tested, and then measure the optical power of the input light after passing through the optical fiber sensitive ring to be tested and returning to the coupler module.

[0036] like Figure 3 As shown, the Lyot depolarizer module 3 of this embodiment is formed by fusing polarization-maintaining optical fibers with a ratio of input-end to output-end polarization-maintaining optical fiber pigtail lengths of 1:2 at a 45° fusing angle, so that the optical signal passing through the coupler is transmitted into the sensitive ring of the optical fiber to be tested in a completely non-polarized form.

[0037] The input end of the Lyot depolarizer module 3 receives the optical signal from the output end c of the coupler module 2, and inputs the optical signal into the optical fiber sensitive ring to be tested. The Lyot depolarizer module 3 plays a role in reducing the influence of the non-reciprocal phase difference introduced by the coupling, birefringence and environmental interference inside the optical fiber sensitive ring on the output light intensity, thereby ensuring the accuracy and reliability of the optical fiber sensitive ring loss test results.

[0038] When measuring the loss of the optical fiber sensitive ring, after the output end pigtail of the Lyot depolarizer module 3 and the pigtail of the optical fiber sensitive ring to be measured are connected through the connector module, the second optical power measurement module 5 is mechanically connected to the composite input and output end b of the coupler module 2 through the second adapter module 6, and the measuring optical signal is input to the optical fiber sensitive ring to be measured. The measuring optical signal is input to the optical fiber sensitive ring to be measured. This can be achieved through an optical power meter, and the optical power meter displays the input power value on the visual interface. The output end of the Lyot depolarizer module 3 is mechanically connected to the first optical power measurement module 4 through the connector module 7 and the first adapter module 8. The optical signal power input to the optical fiber sensitive ring to be measured is measured by the first optical power measurement module 4. This can also be achieved through an optical power meter, and the optical power meter displays the input power value on the visual interface.

[0039] The specific process of using the optical fiber sensitive loop loss test system based on Lyot depolarizer of this embodiment to perform loss test on the optical fiber sensitive loop is as follows:

[0040] Step S1, connect the first optical power measurement module 4 to the polarization-maintaining optical fiber at the output end of the Lyot depolarizer module 3 through the connector module 7 and the first adapter module 8, turn on the system power, wait for 5 seconds, and after the optical fiber sensitive ring loss test system based on the Lyot depolarizer is stably powered, the light source module 1 outputs an optical signal with a central wavelength of 1310nm and stable power, the optical signal is input from the a end of the coupler module 2, output from the c end, and after passing through the Lyot depolarizer module 3, is input into the optical fiber sensitive ring to be tested, turn on the power of the first optical power measurement module 4, set the working wavelength of the polarization-maintaining optical fiber, and record the optical power P1 of the first optical power measurement module 4 at this time; wherein, the working wavelength of the polarization-maintaining optical fiber in this embodiment is set to 1310nm;

[0041] Step S2, disconnecting the connector module 7 from the first adapter module 8, performing polarization-maintaining fusion splicing on the polarization-maintaining optical fiber at the output end of the Lyot depolarizer module 3 and the single end of the optical fiber sensitive ring to be tested, and recording the loss L1 of the Lyot depolarizer module;

[0042] Step S3, connect the second optical power measurement module 5 with the polarization-maintaining optical fiber of the composite input and output end of the coupler module 2 through the second adapter module 6, turn on the power of the second optical power measurement module 5, set the working wavelength of the polarization-maintaining optical fiber (the working wavelength of the polarization-maintaining optical fiber is consistent with that in step S1), and then the optical signal entering the optical fiber sensitive ring to be measured is transmitted to the pigtail end of the polarization-maintaining optical fiber of the optical fiber sensitive environmental protection to be measured, and then returns to the c end of the coupler module along the two polarization-maintaining optical fibers of the Lyot depolarizer module, and is output to the second optical power measurement module 5 through the composite input and output end b end of the Lyot depolarizer module 3 and the coupler module 2, and the power value P2 of the returned optical signal is read by the second optical power measurement module, and recorded;

[0043] Step S4, recording the factory loss value L2 of the coupler module 2;

[0044] Step S5, based on the loss calculation expression E L =10*lg(P1 / P2)-(L1+L2), and the loss value E of the optical fiber sensitive ring to be tested is obtained. L , if the loss value E L If it does not meet the preset requirements, disconnect the welding point in step S2 and weld it again, and then repeat the operation steps in steps S2-S5 to calculate the loss value E. L , if the loss value E is measured three times in a row L If all of them are unqualified, the optical fiber sensitive ring to be tested is determined to be unqualified, and the next optical fiber sensitive ring to be tested will be tested.

[0045] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have the same meaning as in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined similarly here.

[0046] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Fiber sensitive ring loss test system based on Lyot depolarizer, characterized by: The system comprises: a light source module, a coupler module, a first optical power measurement module, a second optical power measurement module, a first adapter module, a second adapter module, a Lyot depolarizer module and a connector module; The light source module is connected to the coupler module to input the low polarization light signal into the coupler module; The coupler module comprises an input end, two output ends and a composite input and output end, the input end of the coupler module is connected to the light source module to receive the optical signal output by the light source module, one output end of the coupler module is connected to the input end of the Lyot depolarizer module, the other output end of the coupler module is a waste end, the composite input and output end of the coupler module is connected to the second optical power measurement module through the second adapter module, and the second optical power measurement module receives the optical signal to be measured returned from the composite input and output end of the coupler module; The first optical power measurement module is connected to the output end of the Lyot depolarizer module through the first adapter module and the connector module; The output end of the Lyot depolarizer module is also connected to the optical fiber sensitive ring to be tested through a connector module.

2. The optical fiber sensitive loop loss test system based on Lyot depolarizer according to claim 1, characterized in that: The light source module comprises an SLD light source and an SLD light source driver. The SLD light source outputs an optical signal with stable power to the coupler module, and the SLD driver performs power driving and temperature control on the SLD light source.

3. The optical fiber sensitive loop loss test system based on Lyot depolarizer according to claim 1, characterized in that: The coupler module includes a 2×2 optical fiber coupler to achieve optical power distribution of optical signals at different output ends.

4. The optical fiber sensitive loop loss test system based on Lyot depolarizer according to claim 3, characterized in that: The optical fiber coupler has a splitting ratio of 1:

1.

5. The optical fiber sensitive loop loss test system based on Lyot depolarizer according to claim 1, characterized in that: The first optical power measurement module is an input optical power measurement module, which is used to measure the optical power input to the sensitive ring of the optical fiber to be tested.

6. The optical fiber sensitive loop loss test system based on Lyot depolarizer according to claim 1, characterized in that: The second optical power measurement module is an output optical power measurement module, which is used to perform polarization-maintaining fusion splicing on the pigtail at the output end of the Lyot depolarizer module and the pigtail of the optical fiber sensitive ring to be tested, and then measure the optical power of the input light after passing through the optical fiber sensitive ring to be tested and returning to the coupler module.

7. The optical fiber sensitive loop loss test system based on Lyot depolarizer according to claim 1, characterized in that: The Lyot depolarizer module is formed by fusing polarization-maintaining optical fibers with fixed length ratios at both ends at a 45° fusing angle, so that the optical signal passing through the coupler is transmitted into the optical fiber sensitive ring in a completely non-polarized form.

8. A method for testing optical fiber sensitive loop loss based on a Lyot depolarizer according to the optical fiber sensitive loop loss testing system based on a Lyot depolarizer according to any one of claims 1 to 7, characterized in that: The method comprises the following operations: Step S1, connecting the first optical power measurement module to the polarization-maintaining optical fiber at the output end of the Lyot depolarizer module through the first adapter module and the connector module, turning on the system power supply, and after the optical fiber sensitive ring loss test system based on the Lyot depolarizer is stably powered, turning on the power supply of the first optical power measurement module, setting the working wavelength of the polarization-maintaining optical fiber, and recording the optical power P1 of the first optical power measurement module at this time, where P1 is the optical power value input to the optical fiber sensitive ring to be tested; Step S2, disconnecting the first adapter module from the connector module, connecting the polarization-maintaining optical fiber at the output end of the Lyot depolarizer module to the single end of the optical fiber sensitive ring to be tested through the connector module, and recording the loss L1 of the Lyot depolarizer module; Step S3, connecting the second optical power measurement module to the polarization-maintaining optical fiber at the composite input and output end of the coupler module through the second adapter module, turning on the power of the second optical power measurement module, setting the working wavelength of the polarization-maintaining optical fiber, and recording the optical power, which is the optical power P2 at this time; Step S4, recording the factory loss value L2 of the coupler module; Step S5, based on the loss calculation expression E L =10*lg(P1 / P2)-(L1+L2), and the loss value E of the optical fiber sensitive ring to be tested is obtained. L , if the loss value E L If it does not meet the preset requirements, disconnect the welding point in step S2 and weld it again, and then repeat the operation steps in steps S2-S5 to calculate the loss value E. L , if the loss value E is measured three times in a row L If all of them are unqualified, the optical fiber sensitive ring to be tested is determined to be unqualified, the single-ended polarization-maintaining optical fiber pigtail of the current optical fiber sensitive ring is removed from the connector module, and the single-ended polarization-maintaining optical fiber pigtail of the next optical fiber sensitive ring to be tested is inserted for the next round of testing.

9. The method for testing the optical fiber sensitive loop loss based on Lyot depolarizer according to claim 8, characterized in that: The operating wavelength of the polarization-maintaining optical fiber set in step S1 is consistent with the operating wavelength of the polarization-maintaining optical fiber set in step S3.

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