A polarization-dependent loss test system and method for titanium diffused straight waveguide chips

Abstract

The present application provides a system and method for testing polarization-dependent loss of titanium diffused straight waveguide chips. After a light source inputs light into the titanium diffused straight waveguide chip to be tested, the light beam output by the titanium diffused straight waveguide chip to be tested is adjusted by a polarization controller to obtain TE mode and TM mode respectively. The optical power of the TE mode and the TM mode is measured respectively by an optical power meter, and the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested can be obtained. In the above scheme, by adding a polarization controller between the titanium diffused straight waveguide chip to be tested and the optical power meter, the polarization controller is adjusted to achieve the polarization-dependent loss test of the titanium diffused straight waveguide chip to be tested, and there is no need to separately output the pigtail for the titanium diffused straight waveguide chip to be tested, which simplifies the test process and saves test time. Moreover, it is not affected by the coupling accuracy between the output pigtail and the titanium diffused straight waveguide chip to be tested, thereby improving the stability and accuracy of the test results.

Description

Technical Field

[0001] The present application relates to the technical field of optical waveguide devices, and in particular to a system and method for testing polarization-dependent loss of a titanium diffused straight waveguide chip. Background Art

[0002] The lithium niobate (Li NbO3) phase modulator chip based on titanium diffusion process [hereinafter referred to as titanium diffusion straight waveguide chip] can transmit two orthogonal polarization modes and introduce a modulation phase difference between them. It is a birefringent phase modulator with the advantages of fast response speed, large modulation bandwidth, easy integration, etc., and is increasingly widely used in optical fiber systems. Due to its importance, its polarization-related loss needs to be tested.

[0003] At present, in the performance test method of titanium diffused straight waveguide chip, since the titanium diffused straight waveguide chip is a dual-polarization working mode, the original technology needs to connect the input end pigtail and the output end pigtail to the chip respectively when the titanium diffused straight waveguide works in different polarization working modes, and then connect the output end pigtail to the extinction ratio tester for measurement. Therefore, the coupling degree between the input end pigtail and the chip and the coupling degree between the output end pigtail and the chip are very high, resulting in a long time in the test process and unstable test data. Summary of the invention

[0004] The technical problem to be solved by the present application is that the existing performance test method of titanium diffused straight waveguide chips has the problems of long time consumption and poor stability. To this end, the present application proposes a polarization-dependent loss test system and method for titanium diffused straight waveguide chips.

[0005] In response to the above technical problems, this application provides the following technical solutions:

[0006] The present application embodiment provides a titanium diffused straight waveguide chip polarization-dependent loss test system, which includes:

[0007] A light source, whose output end is connected to the input end of the titanium diffused straight waveguide chip to be tested, and the light source inputs light to the titanium diffused straight waveguide chip to be tested;

[0008] A polarization controller is arranged behind the output end of the titanium diffused straight waveguide chip to be tested along the light propagation direction, and adjusts the output light of the titanium diffused straight waveguide chip to be tested and then outputs the TE mode and the TM mode;

[0009] An optical power meter is arranged behind the polarization controller along the light propagation direction, receives the TE mode and the TM mode, and measures the optical power of the TE mode and the optical power of the TM mode;

[0010] The loss calculation module obtains the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested according to the optical power of the TE mode and the optical power of the TM mode.

[0011] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, further comprising:

[0012] A lens calibration device, arranged between the polarization controller and the optical power meter along the light propagation direction;

[0013] The lens collimation device is used to calibrate the TE mode and TM mode output by the polarization controller and transmit them to the optical power meter.

[0014] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, wherein the lens calibration device includes a fixed bracket and a lens mounted on the fixed bracket.

[0015] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, wherein the polarization controller includes a fixing device and a front collimating lens, a linear polarization control plate, and a rear collimating lens sequentially arranged on the fixing device.

[0016] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, in which when the linear polarization control plate in the linear polarization controller is rotated to a first angle, the linear polarization controller outputs a TE mode; when the linear polarization control plate in the linear polarization controller is rotated to a second angle, the linear polarization controller outputs a TM mode; the first angle and the second angle have an angle difference of 90°.

[0017] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss testing system is provided, wherein the fixing bracket and the fixing device are configured with a height adjustment portion; the height adjustment portion is adjusted to adjust the lens and the linear polarization control plate to the same height.

[0018] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, further comprising an optical platform:

[0019] The titanium diffused straight waveguide chip to be tested, the polarization controller, the lens calibration device and the optical power module are sequentially arranged on the optical platform along the light propagation direction.

[0020] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, wherein a fixed groove is provided on the surface of the optical platform, and the titanium diffused straight waveguide chip to be tested, the polarization controller, the lens calibration device and the optical power module are sequentially arranged in the fixed groove.

[0021] In some embodiments, a titanium diffused straight waveguide chip polarization-dependent loss test system is provided, wherein the light source is a depolarized light source having the same operating wavelength as the titanium diffused straight waveguide chip to be tested; and the optical power meter has the same operating wavelength as the titanium diffused straight waveguide chip to be tested.

[0022] The embodiment of the present application also provides a method for testing polarization-dependent loss of a titanium diffused straight waveguide chip. The polarization-dependent loss of a titanium diffused straight waveguide chip is tested by using the titanium diffused straight waveguide chip polarization-dependent loss testing system described in any of the above schemes. The method comprises the following steps:

[0023] Step 1: Arrange the light source, the titanium diffused straight waveguide chip to be tested, the polarization controller and the optical power meter in sequence along the light propagation direction;

[0024] Step 2: Start the light source to input light to the titanium diffused straight waveguide chip to be tested;

[0025] Step 3: adjusting the polarization controller to adjust the output light of the titanium diffused straight waveguide chip to be tested to the TE mode and the TM mode;

[0026] Step 4: The optical power meter obtains the optical power of the TE mode when receiving the TE mode, and obtains the optical power of the TM mode when receiving the TM mode;

[0027] Step 5: Obtain the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested according to the optical power of the TE mode and the optical power of the TM mode.

[0028] The technical solution of this application has the following technical effects compared with the prior art:

[0029] The present application provides a system and method for testing polarization-dependent loss of titanium diffused straight waveguide chips. After a light source inputs light into the titanium diffused straight waveguide chip to be tested, the output light of the titanium diffused straight waveguide chip to be tested is adjusted by a polarization controller to obtain TE mode and TM mode respectively. Then, an optical power meter is used to measure the optical power of the TE mode and the TM mode respectively, thereby obtaining the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested. In the above scheme, by adding a polarization controller between the titanium diffused straight waveguide chip to be tested and the optical power meter, the polarization-dependent loss test purpose of the titanium diffused straight waveguide chip to be tested is achieved by adjusting the polarization controller. There is no need to dock the output tail fibers for different polarization modes of the titanium diffused straight waveguide chip to be tested, which simplifies the test process and saves test time. In addition, there is no need to be affected by the coupling accuracy between the output tail fiber and the titanium diffused straight waveguide chip to be tested, thereby improving the stability and accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, which will help to understand the purpose and advantages of the present application, wherein:

[0031] Figure 1 This is a schematic diagram of the structure of a titanium diffused straight waveguide chip according to an embodiment of the present application;

[0032] Figure 2 This is a structural block diagram of a polarization-dependent loss test system for a titanium diffused straight waveguide chip according to an embodiment of the present application;

[0033] Figure 3 This is a structural block diagram of a polarization-dependent loss test system for a titanium diffused straight waveguide chip according to another embodiment of the present application;

[0034] Figure 4 A schematic diagram of the arrangement of a polarization controller, a lens calibration device, and an optical power meter according to an embodiment of the present application;

[0035] Figure 5 A schematic diagram of a fixing groove on the surface of an optical platform according to an embodiment of the present application;

[0036] Figure 6 This is a flow chart of a method for testing polarization-dependent loss of a titanium diffused straight waveguide chip according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0038] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0041] The present application embodiment provides a titanium diffused straight waveguide chip polarization dependent loss test system, such as Figure 1 and Figure 2 As shown, the system is used to test a titanium diffused straight waveguide chip 100 to be tested, wherein the titanium diffused straight waveguide chip 100 to be tested comprises a titanium diffused chip and a straight waveguide embedded in the center line position of the upper surface of the titanium diffused chip, wherein the left end of the titanium diffused straight waveguide is a light input end A, and the right end of the titanium diffused straight waveguide is a light output end B. The system comprises a light source 201, a polarization controller 202 and an optical power meter 203, wherein:

[0042] The light source 201, whose output end is connected to the input end A of the titanium diffused straight waveguide chip 100 to be tested, can be specifically connected to the titanium diffused straight waveguide chip 100 to be tested by using the input end pigtail 101 as a transmission medium, and the light source 201 inputs light to the titanium diffused straight waveguide chip 100 to be tested; the polarization controller 202 is arranged behind the output end B of the titanium diffused straight waveguide chip 100 to be tested along the light propagation direction, and adjusts the output light of the titanium diffused straight waveguide chip 100 to be tested and outputs the TE mode and the TM mode; the optical power meter 203 is arranged behind the polarization controller 202 along the light propagation direction, receives the TE mode and the TM mode, and measures the optical power of the TE mode and the optical power of the TM mode; the above system can also include a loss calculation module, which obtains the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested according to the optical power of the TE mode and the optical power of the TM mode. Specifically, the polarization-dependent loss PDL can be calculated by the following formula:

[0043] PDL=|10l g(P TE / P TM )|;

[0044] Among them, P TE is the optical power in TE mode, P TM is the optical power in TM mode.

[0045] In the above scheme provided by the present embodiment, after the light source 201 inputs light to the titanium diffused straight waveguide chip 100 to be tested, the output light of the titanium diffused straight waveguide chip 100 to be tested is adjusted by the polarization controller 202 to obtain the TE mode and the TM mode respectively, and then the optical power meter 203 is used to measure the optical power of the TE mode and the TM mode respectively, so as to obtain the polarization-dependent loss of the titanium diffused straight waveguide chip 100 to be tested. In the above scheme, by adding the polarization controller 202 between the titanium diffused straight waveguide chip 100 to be tested and the optical power meter 203, the polarization-dependent loss test purpose of the titanium diffused straight waveguide chip 100 to be tested is achieved by adjusting the polarization controller 202, and there is no need to dock the output pigtails for different polarization modes of the titanium diffused straight waveguide chip 100 to be tested, which simplifies the test process and saves the test time. In addition, there is no need to be affected by the coupling accuracy between the output pigtail and the titanium diffused straight waveguide chip 100 to be tested, thereby improving the stability and accuracy of the test results.

[0046] like Figure 3 As shown, the polarization-dependent loss test system of the titanium diffused straight waveguide chip in the above scheme may also include a lens calibration device 204, which is arranged between the polarization controller 202 and the optical power meter 203 along the light propagation direction; the lens collimation device 204 is used to calibrate the TE mode and TM mode output by the polarization controller 202 and transmit them to the optical power meter 204. Although the polarization controller 202 is connected to the optical power meter 203 through the lens calibration device 204 in this embodiment, it is not limited to this connection method. The lens calibration device 204 can realize the collimation processing of the TE mode and the TM mode, so that the loss of the light beam before entering the optical power meter 203 is reduced. In the specific implementation, the distance between the optical power meter 203 and the lens calibration device 204, and the distance between the lens calibration device 204 and the polarization controller 202 can be adaptively adjusted so that the detection result value of the optical power meter 203 reaches the maximum.

[0047] In some embodiments, in the above titanium diffused straight waveguide chip polarization-dependent loss test system, the lens calibration device 204 includes a fixed bracket and a lens mounted on the fixed bracket. The fixed bracket can be easily installed and moved, and the angle, height, etc. of the lens can also be adjusted.

[0048] Preferably, in the polarization-dependent loss test system for titanium diffused straight waveguide chips in the above scheme, the polarization controller 202 includes a fixing device and a front collimating lens, a linear polarization control plate and a rear collimating lens sequentially arranged on the fixing device. The linear polarization control plate can be implemented by an existing linear polarizer. When the angle of the linear polarizer is adjusted to an appropriate value, linear polarized light in a certain direction can pass through, while light with a polarization direction perpendicular to it cannot pass through and will be absorbed or reflected in other directions. For example, it can only pass through the TE mode. After that, if it is rotated by 90°, it can only pass through the TM mode. The linear polarizer can ensure that the output light beam has a very high degree of polarization. Arranging collimating lenses before and after the linear polarizer can further improve the straightness of the light beam and reduce transmission loss.

[0049] In the above scheme, as mentioned above, when the linear polarization control plate in the linear polarization controller 202 is rotated to a first angle, the linear polarization controller 202 outputs one of the modes TE or TM; when the linear polarization control plate in the linear polarization controller 202 is rotated to a second angle, the linear polarization controller 202 outputs another mode different from the first angle; the first angle and the second angle have an angle difference of 90°. In this scheme, when testing the titanium diffused straight waveguide chip 100 to be tested, the two modes of light emitted by the light source 201 can be polarized separately by rotating the polarization controller 202, thereby achieving polarization-dependent loss testing of the titanium diffused straight waveguide chip 100 to be tested, without requiring the output fiber tail to be coupled with the titanium diffused straight waveguide chip 100 to be tested, simplifying the structure of the system and ensuring the accuracy of the test results.

[0050] In the above scheme, the titanium diffused straight waveguide chip polarization-dependent loss test system, the fixing bracket and the fixing device are configured with a height adjustment part; the height adjustment part is adjusted to adjust the lens and the linear polarization control plate to the same height. Thus, the height of each collimating lens and the linear polarization control plate can be kept consistent.

[0051] The titanium diffused straight waveguide chip polarization-dependent loss test system in the above scheme is as follows: Figure 4 and Figure 5 As shown, an optical platform 300 may also be included, and the titanium diffused straight waveguide chip 100 to be tested, the polarization controller 202, the lens calibration device 204 and the optical power module 203 are sequentially arranged on the optical platform 300 along the light propagation direction. The stability of each component can be ensured by fixing and installing each component on the optical platform 300. Figure 5As shown, a fixing groove 301 is provided on the surface of the optical platform 300 in the polarization-dependent loss test system for titanium diffused straight waveguide chips, and the titanium diffused straight waveguide chip 100 to be tested, the polarization controller 202, the lens calibration device 204 and the optical power module 203 are all arranged in the fixing groove 301. By providing the fixing groove 301, it can be further ensured that each component can be arranged along the light propagation direction during installation.

[0052] In the above scheme, the light source 201 is a depolarized light source having the same working wavelength as the titanium diffused straight waveguide chip 100 to be tested; the optical power meter 203 has the same working wavelength as the titanium diffused straight waveguide chip 100 to be tested, which can achieve the lowest loss of the light beam during transmission.

[0053] In some embodiments, Figure 6 As shown, a method for testing polarization-dependent loss of a titanium diffused straight waveguide chip is also provided. The polarization-dependent loss of a titanium diffused straight waveguide chip is tested by using the polarization-dependent loss testing system for a titanium diffused straight waveguide chip described in any of the above schemes. The method comprises the following steps:

[0054] Step 1: Arrange the light source, the titanium diffused straight waveguide chip to be tested, the polarization controller and the optical power meter in sequence along the light propagation direction. In some preferred embodiments, a lens calibration device may also be provided between the polarization controller and the optical power meter, in which case the lens calibration device and the polarization controller are adjusted to the same level.

[0055] Step 2: Start the light source and input light to the titanium diffused straight waveguide chip to be tested. At this time, the lens calibration device can also be adjusted to make the optical power value of the light emitted from the light source passing through the lens calibration device reach the maximum value.

[0056] Step 3: Adjust the polarization controller to adjust the output light of the titanium diffused straight waveguide chip to be measured into the TE mode and the TM mode. The polarization controller is used to measure the optical power of the light output by the titanium diffused straight waveguide chip in the TE and TM modes.

[0057] Step 4: The optical power meter obtains the optical power of the TE mode when receiving the TE mode, and obtains the optical power of the TM mode when receiving the TM mode.

[0058] Step 5: Obtain the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested according to the optical power of the TE mode and the optical power of the TM mode.

[0059] In the above method, by adding a polarization controller between the titanium diffused straight waveguide chip and the optical power meter, the polarization controller is rotated to achieve the purpose of testing the polarization-dependent loss of the titanium diffused straight waveguide chip, without the need to dock the output end of the titanium diffused straight waveguide chip with the pigtail, thereby meeting the requirements for testing large quantities of high-efficiency titanium diffused straight waveguide chips. The test method used in this embodiment can avoid the polarization-dependent loss being affected during the test process due to the failure to fix the output pigtail in the original test method, and facilitates accurate testing.

[0060] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A titanium diffused straight waveguide chip polarization-dependent loss test system, characterized in that: include: A light source, whose output end is connected to the input end of the titanium diffused straight waveguide chip to be tested, and the light source inputs light to the titanium diffused straight waveguide chip to be tested; A polarization controller is arranged behind the output end of the titanium diffused straight waveguide chip to be tested along the light propagation direction, and adjusts the output light of the titanium diffused straight waveguide chip to be tested and then outputs the TE mode and the TM mode; An optical power meter is arranged behind the polarization controller along the light propagation direction, receives the TE mode and the TM mode, and measures the optical power of the TE mode and the optical power of the TM mode; The loss calculation module obtains the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested according to the optical power of the TE mode and the optical power of the TM mode.

2. The titanium diffused straight waveguide chip polarization-dependent loss test system according to claim 1, characterized in that: Also includes: A lens calibration device, arranged between the polarization controller and the optical power meter along the light propagation direction; The lens collimation device is used to calibrate the TE mode and TM mode output by the polarization controller and transmit them to the optical power meter.

3. The titanium diffused straight waveguide chip polarization-dependent loss test system according to claim 2, characterized in that: The lens calibration device comprises a fixing bracket and a lens mounted on the fixing bracket.

4. The titanium diffused straight waveguide chip polarization-dependent loss test system according to claim 3, characterized in that: The polarization controller comprises a fixing device and a front collimating lens, a linear polarization control plate and a rear collimating lens which are sequentially arranged on the fixing device.

5. The titanium diffused straight waveguide chip polarization-dependent loss test system according to claim 4, characterized in that: When the linear polarization control plate in the polarization controller is rotated to a first angle, the polarization controller outputs a TE mode; when the linear polarization control plate in the polarization controller is rotated to a second angle, the polarization controller outputs a TM mode; the first angle and the second angle have an angle difference of 90°.

6. The titanium diffused straight waveguide chip polarization-dependent loss test system according to claim 5, characterized in that: The fixing bracket and the fixing device are provided with a height adjusting portion; the height adjusting portion is adjusted to adjust the lens and the linear polarization control plate to the same height.

7. The titanium diffused straight waveguide chip polarization-dependent loss test system according to any one of claims 2 to 6, characterized in that: Also includes optical bench: The titanium diffused straight waveguide chip to be tested, the polarization controller, the lens calibration device and the optical power meter are sequentially arranged on the optical platform along the light propagation direction.

8. The titanium diffused straight waveguide chip polarization-dependent loss test system according to claim 7, characterized in that: A fixing groove is provided on the surface of the optical platform, and the titanium diffused straight waveguide chip to be tested, the polarization controller, the lens calibration device and the optical power meter are arranged in the fixing groove in sequence.

9. The titanium diffused straight waveguide chip polarization-dependent loss test system according to any one of claims 1 to 6, characterized in that: The light source is a depolarized light source having the same working wavelength as the titanium diffused straight waveguide chip to be measured; the optical power meter has the same working wavelength as the titanium diffused straight waveguide chip to be measured.

10. A method for testing polarization-dependent loss of titanium diffused straight waveguide chips, characterized in that: The polarization-dependent loss of a titanium diffused straight waveguide chip is tested by using the titanium diffused straight waveguide chip polarization-dependent loss test system according to any one of claims 1 to 9, and the method comprises the following steps: Step 1: Arrange the light source, the titanium diffused straight waveguide chip to be tested, the polarization controller and the optical power meter in sequence along the light propagation direction; Step 2: Start the light source to input light to the titanium diffused straight waveguide chip to be tested; Step 3: adjusting the polarization controller to adjust the output light of the titanium diffused straight waveguide chip to be tested to the TE mode and the TM mode; Step 4: The optical power meter obtains the optical power of the TE mode when receiving the TE mode, and obtains the optical power of the TM mode when receiving the TM mode; Step 5: Obtain the polarization-dependent loss of the titanium diffused straight waveguide chip to be tested according to the optical power of the TE mode and the optical power of the TM mode.

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