Device and method for measuring extinction ratio of ASE light source

Abstract

The invention relates to a device for testing the extinction ratio of an ASE light source of a fiber-optic gyroscope. The device comprises the ASE light source, a half-wave plate, a polarization beam splitter and two power meters, the ASE light source is a measured object; the half-wave plate is arranged between the ASE light source and the polarization beam splitter and is used for adjusting the polarization direction of light entering the polarization beam splitter; the polarization beam splitter is used for splitting input polarized light into two beam splitting light in the orthogonal polarization direction; and the two power meters are respectively arranged behind the two output ends of the polarization beam splitter and are used for measuring the optical power of the two split beams in the orthogonal polarization direction. The device is simple in structure, flexible to construct, low in cost and accurate in measurement.

Description

Technical Field

[0001] The present invention relates to the field of fiber optic gyroscopes, and in particular to a testing device and method for measuring the extinction ratio of an ASE light source. Background Art

[0002] In the application of ASE light sources, the extinction ratio is an important parameter for evaluating its polarization purity and system adaptability, and plays a key role in polarization-sensitive scenarios such as fiber optic gyroscopes. By measuring the extinction ratio, the polarization characteristics of the light source can be evaluated to ensure the stability of its main polarization direction, thereby improving the quality of the interference signal and the measurement accuracy of the system. In addition, the extinction ratio test is also used to evaluate the stability of the light source in a dynamic environment (such as temperature changes or mechanical disturbances), and to optimize the polarization performance in the manufacture and design of the light source, thereby enhancing the application adaptability of the ASE light source and the overall system performance. The extinction ratio test usually requires the use of a professional extinction ratio tester, which is expensive and complex in structure, and is not suitable for use in simple fiber optic gyroscope systems or experimental environments. Therefore, there is an urgent need for an extinction ratio test device with a simple structure, low cost and accurate measurement.

[0003] Li Yan and others from the Beijing University of Aeronautics and Astronautics proposed a solution of rotating the analyzer prism. This method measures the optical power in the main polarization direction and the orthogonal polarization direction of the light by rotating the polarization beam splitter, and then calculates the extinction ratio. However, this solution has many shortcomings. First, the device structure is complex, and the rotating polarization beam splitter needs to be equipped with complex high-precision mechanical devices, which increases the construction and maintenance costs of the system. Secondly, due to the large thickness of the polarization beam splitter, the deflection relative to the optical axis during assembly will cause the light spot to shift during rotation, and this shift will significantly affect the stability and accuracy of the measurement. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a device and method for measuring the extinction ratio of an ASE light source, which has a simple structure, flexible construction, low cost and accurate measurement.

[0005] One of the above objects of the present invention is achieved by the following technical solution:

[0006] A test device for the extinction ratio of an optical fiber gyroscope ASE light source, comprising: an ASE light source, a half wave plate, a polarization beam splitter and two power meters;

[0007] The ASE light source is the object to be measured;

[0008] The half wave plate is disposed between the ASE light source and the polarization beam splitter, and is used to adjust the polarization direction of the light incident on the polarization beam splitter;

[0009] The polarization beam splitter is used to split the input polarized light into two beams of orthogonal polarization directions;

[0010] The two power meters are respectively arranged after the two output ends of the polarization beam splitter and are used for measuring the optical powers of the two split beams of light in the orthogonal polarization directions.

[0011] One of the above-mentioned objects of the present invention is achieved by the following technical solutions:

[0012] A method for testing the extinction ratio of an ASE light source of an optical fiber gyroscope, using the above-mentioned testing device for the extinction ratio of the ASE light source of the optical fiber gyroscope, includes:

[0013] Step 1: Output laser from the ASE light source and transmit it to the half-wave plate.

[0014] Step 2: Control the polarization direction of the light by adjusting the angle of the half-wave plate to make it match the polarization beam splitter.

[0015] Step 3: Divide the incident light into two split beams of light in two mutually orthogonal polarization directions through the polarization beam splitter.

[0016] Step 4: Measure the optical powers of the two split beams of light through two power meters to obtain two optical power values.

[0017] Step 5: Calculate the extinction ratio according to the two measured optical power values.

[0018] Moreover, in Step 5, the formula for calculating the extinction ratio is:

[0019]

[0020] where P ∥ is the optical power in the main polarization direction, and P ⊥ is the optical power in the orthogonal polarization direction.

[0021] The advantages and positive effects of the present invention are:

[0022] 1. The present invention proposes an extinction ratio testing scheme based on a polarization beam splitter (PBS) and a half-wave plate (HWP), which significantly optimizes the existing testing method. By using a half-wave plate with a thickness much smaller than that of the polarization beam splitter to adjust the polarization direction of the light, the problem of spot offset during rotation can be effectively alleviated, and the measurement accuracy can be improved. At the same time, the polarization beam splitter does not need to be rotated, and the measurement can be completed only by rotating the wave plate, reducing the mechanical complexity and the requirements for assembly accuracy.

[0023] 2. The present invention adopts the combination of a polarization beam splitter and a half-wave plate, eliminating the need for complex extinction ratio testing instruments, and having the advantages of simple structure and low cost.

[0024] 3. The device of the present invention can be flexibly built according to actual needs and is suitable for laboratory and on-site measurements.

[0025] 4. By rotating the half-wave plate (the rotation control uses existing mature auxiliary devices), the polarization direction of light can be precisely adjusted to match the polarization beam splitter, thereby improving the accuracy of extinction ratio measurement.

[0026] 5. With the device of the present invention, a power meter can also be used to record the power value sequence over time, so as to study the change of the extinction ratio of the light source under full temperature conditions.

[0027] In summary, the present invention provides an economical and efficient extinction ratio test solution for the field of fiber optic gyroscopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of the extinction ratio test device according to an embodiment of the present invention;

[0029] Figure 2 is a physical diagram of the extinction ratio test device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The structure of the present invention will be further described below with reference to the drawings and through embodiments. It should be noted that this embodiment is narrative rather than restrictive.

[0031] A test device for the extinction ratio of an ASE light source of a fiber optic gyroscope, please refer to Figure 1 - Figure 2 , including: an ASE light source, which is the object to be measured; a polarization beam splitter, which is used to divide the input polarized light into two components with orthogonal polarization directions; power meters, which are respectively arranged after the two output ends of the polarization beam splitter and are used to measure the optical powers of the two split beams of light with orthogonal polarization directions; a half-wave plate, which is arranged between the ASE light source and the polarization beam splitter and is used to adjust the polarization direction of the light incident on the polarization beam splitter.

[0032] The laser output from the ASE light source 1 passes through the half-wave plate 2 to adjust the polarization direction of the output light. The adjusted light enters the polarization beam splitter 3, which divides the incident light into two split beams of light with two mutually orthogonal polarization directions; the two split beams of light are respectively output and pass through two power meters to measure the optical powers. Using the two measured optical power values, the extinction ratio can be calculated, and the formula is:

[0033]

[0034] where P ∥ is the optical power in the main polarization direction, and P ⊥ is the optical power in the orthogonal polarization direction.

[0035] As described above, by adjusting the angle of the half wave plate 2, the polarization direction of the light can be controlled to match the polarization beam splitter, that is, by rotating the wave plate, the optical power ratio of the two orthogonal polarization directions is maximized.

[0036] Figure 2 This is a physical picture of the extinction ratio test device of the present invention. The test device has a simple structure, convenient adjustment, easy implementation, flexible construction, unlimited applicable places, and good environmental applicability.

[0037] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A test device for the extinction ratio of an optical fiber gyroscope ASE light source, characterized in that: include: ASE light source, half wave plate, polarization beam splitter and two power meters; The ASE light source is the object to be measured; The half wave plate is disposed between the ASE light source and the polarization beam splitter, and is used to adjust the polarization direction of the light incident on the polarization beam splitter; The polarization beam splitter is used to split the input polarized light into two beams of orthogonal polarization directions; The two power meters are respectively arranged behind the two output ends of the polarization beam splitter and are used to measure the optical power of the two split beams in orthogonal polarization directions.

2. A method for testing the extinction ratio of an optical fiber gyroscope ASE light source, characterized in that: The device for testing the extinction ratio of the fiber optic gyroscope ASE light source according to claim 1 comprises the following steps: Step 1: The ASE light source outputs laser light and transmits it to a half-wave plate; Step 2: Control the polarization direction of the light by adjusting the angle of the half wave plate to match the polarization beam splitter; Step 3, splitting the incident light into two beams with orthogonal polarization directions through a polarization beam splitter; Step 4: measure the optical power of the two split beams by two power meters to obtain two optical power values; Step 5: Calculate the extinction ratio based on the two measured optical power values.

3. According to the method for testing the output extinction ratio of the fiber optic gyroscope ASE light source according to claim 2, in step 5, the formula for calculating the extinction ratio is: in, P ∥ is the optical power in the main polarization direction, P ⊥ is the optical power in the orthogonal polarization direction.

Images