Device for testing degree of polarization of laser

Abstract

The invention provides a laser polarization degree testing device, which is applied to the technical field of detection, and comprises a thin film circuit, the surface of which is provided with an electrode contact of a laser; a clamping groove is formed in the bearing surface of the laser limiting device; the conductive assembly is arranged in the direction, close to the bearing surface, of the laser limiting device, the conductive assembly comprises a supporting structure and at least two conductive contacts, the supporting structure can move up and down along a guide rail perpendicular to the bearing surface, and the conductive contacts are fixed to the supporting structure and perpendicularly correspond to the electrode contacts in position; a through hole is formed in the axis of the rotating table, and the polaroid is fixedly arranged on the bearing surface of the rotating table; the photodiode is vertically arranged in the light emitting direction of the polaroid, and the photosensitive surface of the photodiode is coaxial with the rotating table; the controller is electrically connected with the conductive assembly, the rotating table and the photodiode through wires. And the universality and the operation convenience of the device can be enhanced.

Description

Technical Field

[0001] This application relates to the field of detection technology, and in particular to a device for testing the polarization degree of a laser. Background Art

[0002] In the field of semiconductor micro-electro-mechanical systems (MEMS) device integration, lasers have a great impact on the overall performance of the optical path. However, due to the small chip size of some lasers, such as vertical-cavity surface-emitting lasers (VCSELs), it is difficult to control the operation difficulty and test consistency of their performance tests. In traditional test systems, each time a test sample is replaced, each component needs to be recalibrated according to the laser to be tested, and the test efficiency is low. Summary of the Invention

[0003] An embodiment of this application provides a device for testing the polarization degree of a laser to solve the problem of low test efficiency of traditional devices for testing the polarization degree of a laser.

[0004] To solve the above technical problem, an embodiment of this application provides a device for testing the polarization degree of a laser, including: a thin-film circuit, on the first surface of which electrode contacts of the laser are provided; a laser limiting device, which has a slot on the bearing surface for fixedly placing the thin-film circuit; a conductive component, which is arranged in the direction close to the bearing surface of the laser limiting device. The conductive component includes a support structure that can move up and down along a guide rail perpendicular to the bearing surface and at least two conductive contacts. The conductive contacts are fixed to the support structure and are vertically corresponding to the electrode contacts. When testing the polarization degree of the laser, the conductive component moves in the direction close to the slot, so that the conductive contacts contact the electrode contacts and form an electrical connection; a rotating table, with a through hole opened at the center of the rotating table, and a polarizer is fixedly arranged on the receiving surface of the rotating table; a photodiode, which is vertically arranged in the light-emitting direction of the polarizer, and the photosensitive surface of the photodiode is coaxial with the rotating table; a controller, which is electrically connected to the conductive component, the rotating table and the photodiode through wires respectively. The controller is used to control the rotation of the rotating table, supply power to the conductive component, collect the output signal of the photodiode and calculate the polarization degree of the laser.

[0005] One of the above technical solutions has the following advantages or beneficial effects: In an embodiment of the present application, a thin-film circuit is included. An electrode contact of a laser is provided on a first surface of the thin-film circuit; a laser limiting device, a slot for fixedly placing the thin-film circuit is provided on a bearing surface of the laser limiting device; a conductive component, the position where the conductive component is provided is in a direction close to the bearing surface of the laser limiting device. The conductive component includes a support structure that can move up and down along a guide rail perpendicular to the bearing surface and at least two conductive contacts. The conductive contacts are fixed to the support structure and are vertically corresponding to the positions of the electrode contacts. When testing the polarization degree of the laser, the conductive component moves in a direction close to the slot, so that the conductive contacts are in contact with the electrode contacts to form an electrical connection; a rotating table, a through hole is provided at the axis of the rotating table, and a polarizer is fixedly arranged on a receiving surface of the rotating table; a photodiode, the photodiode is vertically arranged in an outgoing light direction of the polarizer, and a photosensitive surface of the photodiode is coaxial with the rotating table; a controller, the controller is electrically connected to the conductive component, the rotating table and the photodiode through wires respectively. The controller is used to control the rotation of the rotating table, supply power to the conductive component, collect an output signal of the photodiode and calculate the polarization degree of the laser. In the embodiment of the present application, the thin-film circuit is accurately positioned by the slot of the laser limiting device, and the reliable contact and electrical connection of the microelectrodes are realized by cooperating with the vertically movable conductive contacts, which can reduce the unstable contact situation during the test of small-size devices. The coaxial layout of the through hole at the axis of the rotating table, the polarizer and the photodiode ensures that the laser beam is vertically incident on the photosensitive surface, reduces the optical path offset error, and improves the optical signal acquisition accuracy. In addition, the controllable movement of the conductive component along the vertical guide rail is compatible with the electrode layouts of different specifications of lasers, enhances the versatility and operation convenience of the device, and thus improves the test efficiency of the polarization degrees of different specifications of lasers. Description of the Drawings

[0006] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0007] Figure 1 It is a schematic structural diagram of a laser polarization degree testing device provided by an embodiment of the present application. Detailed Embodiments

[0008] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0009] As Figure 1 shown, an embodiment of the present invention provides a device for testing the polarization degree of a laser. As Figure 1 shown, it includes: A thin-film circuit 2, on the first surface of which electrode contacts of the laser are provided; A laser limiting device 3, which has a card slot for fixedly placing the thin-film circuit 2 on the bearing surface; A conductive component 1, which is arranged in the direction close to the bearing surface of the laser limiting device 3. The conductive component 1 includes a support structure that can move up and down along a guide rail perpendicular to the bearing surface and at least two conductive contacts. The conductive contacts are fixed to the support structure and are vertically corresponding to the positions of the electrode contacts. In the case of testing the polarization degree of the laser, the conductive component 1 moves in the direction close to the card slot, so that the conductive contacts contact the electrode contacts and form an electrical connection; A rotating table 5, with a through hole opened at the axis of the rotating table 5, and the polarizer is fixedly arranged on the receiving surface of the rotating table 5; A photodiode 6, which is vertically arranged in the light-emitting direction of the polarizer, and the photosensitive surface of the photodiode 6 is coaxial with the rotating table 5; A controller 7, which is electrically connected to the conductive component 1, the rotating table 5 and the photodiode 6 through wires respectively. The controller 7 is used to control the rotation of the rotating table 5, supply power to the conductive component 1, collect the output signal of the photodiode 6 and calculate the polarization degree of the laser.

[0010] In the embodiment of the present invention, taking Figure 1 as an example, the electrodes of the above-mentioned laser can be electrically connected to the electrode contacts of the thin-film circuit 2 by welding or wire bonding. For example, they can be directly welded to the first surface of the thin-film circuit 2 through surface mount technology, and the positive electrode can be connected to the positive electrode solder joint of the thin-film circuit 2 by gold wire bonding; in addition, the electrodes of the laser and the electrode contacts of the thin-film circuit 2 can also be connected by anisotropic conductive adhesive, and the conductive adhesive can form a conductive path after high-temperature curing, or by other means. In this regard, the embodiments of the present application do not make specific limitations.

[0011] The above-mentioned thin-film circuit 2 is mechanically fixed through the above-mentioned card slot, and the positions of the electrode contacts and the conductive contacts are ensured to correspond. In some alternative embodiments, elastic limiting protrusions may be provided on the inner wall of the above-mentioned card slot for providing a pre-tightening force in the horizontal direction when the thin-film circuit 2 is placed in the card slot. A positioning pin may also be provided at the bottom of the card slot, and a positioning hole is provided at the corresponding position of the thin-film circuit 2, and the cooperation of the positioning pin and the positioning hole can be used to strengthen the mechanical fixation of the thin-film circuit 2.

[0012] The above-mentioned conductive component 1 can move along a guide rail perpendicular to the bearing surface to achieve contact or separation from the electrode contacts. The above-mentioned guide rail can be designed as an integral part of the housing 8. The support structure can be fixedly connected with a pressing rod at the top. The pressing rod extends outside the housing 8 of the device and forms an operation handle. A return spring is sleeved outside the guide rail. When the operation handle is manually pressed downward, the support structure moves downward along the guide rail, and the conductive contact touches the electrode contact. In some alternative embodiments, a limiting buckle may be provided between the pressing rod and the housing 8 for locking the position of the pressing rod when the conductive contact touches the electrode contact.

[0013] In some other alternative embodiments, the conductive contact may include a main probe and at least one auxiliary probe, and the length of the auxiliary probe is longer than that of the main probe. The auxiliary probe can be connected to the support structure through an independent elastic structure, and the elastic coefficient of the elastic structure is smaller than the elastic coefficients of the return spring and the elastic structure of the main probe. When the operation handle is manually pressed, the auxiliary probe touches the electrode contact before the main probe for detecting the contact resistance. If the contact resistance exceeds a preset threshold, it can be prompted to readjust the position of the thin-film circuit 2. After releasing the operation handle, the return spring drives the support structure to return to the initial position.

[0014] In some other alternative embodiments, the guide rail can be a linear ball guide rail, and the support structure can be slidably connected to the guide rail through a slider. A spring buffer mechanism can also be provided between the support structure and the guide rail for providing buffering when the conductive contact touches the electrode contact to avoid damaging the electrode surface.

[0015] The above polarizer is fixed to the receiving surface of the rotating table 5. The axial through-hole of the rotating table 5 ensures the coaxiality of the optical path. For the fixing method of the polarizer, the embodiments of the present application do not make specific limitations. The above polarizer can be pasted on the receiving surface of the rotating table 5 through optical glue; or an annular groove can be provided on the receiving surface of the rotating table 5, and the edge of the polarizer is embedded in the groove and fixed by a retaining ring. Different fixing methods do not affect the realization of the basic functions of the laser polarization degree testing device in the embodiments of the present application. The above photodiode 6 is vertically arranged in the light-emitting direction of the polarizer, and the photosensitive surface is coaxial with the rotating table 5; specifically, the above photodiode 6 can be fixed below the rotating table 5 through a metal support column, or a diaphragm can be provided around the photodiode 6 to limit the angular range of the incident light so as to improve the acquisition accuracy of the optical signal.

[0016] The above controller 7 controls and transmits signals to the conductive component 1, the rotating table 5, and the photodiode 6 through wires. For the materials, materials, and specific models of the above wires, the embodiments of the present application also do not make specific limitations.

[0017] Exemplarily, the complete usage steps of the above laser polarization degree testing device can be as follows: The controller 7 powers on the laser polarization degree testing device and controls the rotating table 5 to start rotating at a constant speed; Start the controller 7 and turn on the test program; Place the thin film circuit 2 welded with the VCSEL laser in the fixed card slot; Press down the support structure of the above conductive component 1 to make the conductive contact touch the electrode of the thin film circuit 2; The photodiode 6 converts the optical signal into an electrical signal and feeds back the test value through the controller 7.

[0018] In some alternative embodiments, the controller 7 includes a test program control circuit system, which can supply power to the laser and process the light intensity received by the photodiode 6 into a value.

[0019] In this embodiment, the thin film circuit 2 is accurately positioned through the card slot of the laser limiting device 3, and the reliable contact and electrical connection of the microelectrodes are realized by cooperating with the vertically movable conductive contact. The situation of unstable contact during the test of small-sized devices can be reduced. The coaxial layout of the axial through-hole of the rotating table 5, the polarizer, and the photodiode 6 ensures that the laser beam is vertically incident on the photosensitive surface, reduces the optical path deviation error, and improves the acquisition accuracy of the optical signal. In addition, the controllable movement of the conductive component 1 along the vertical guide rail is compatible with the electrode layouts of different specifications of lasers, enhances the versatility and operation convenience of the device, and also improves the test efficiency.

[0020] Optionally, the negative electrode of the laser is welded to the second surface of the thin film circuit 2 and connected to the negative electrode contact of the electrode contact through a first through hole, and the positive electrode of the laser is transferred to the positive electrode solder joint on the second surface by wire bonding and connected to the positive electrode contact of the electrode contact through a second through hole.

[0021] In this embodiment, the negative electrode of the above-mentioned laser can be directly fixed on the second surface of the thin film circuit 2 through a welding process such as reflow soldering. The negative electrode solder joint on the second surface is electrically connected to the negative electrode contact on the first surface through a first through hole vertically penetrating the thin film circuit 2. A metal layer can be plated on the inner wall of the first through hole to form a conductive path to ensure that current is conducted from the negative electrode contact to the negative electrode of the laser through the through hole. The positive electrode of the above-mentioned laser can be connected to the positive electrode solder joint on the second surface by wire bonding with a gold wire. The positive electrode solder joint can be electrically connected to the positive electrode contact on the first surface through a second through hole, so that current is conducted from the positive electrode contact to the positive electrode of the laser through the through hole and the gold wire. The size of the above-mentioned through hole and the thickness of the metal layer are not specifically limited in the embodiments of the present application.

[0022] In this embodiment, through the through hole structure, the laser electrodes are led out from the second surface to the first surface, solving the problem of space limitation of single-sided wiring of the thin film circuit 2, improving the adaptability to the test of high-density integrated micro lasers. In addition, compared with the traditional surface wire bonding method, the through hole connection path is shorter, reducing signal transmission loss. The electrode contacts are concentrated on the first surface. Through the through hole transfer technology, the electrode signals can be efficiently led out from the bottom of the device to the test plane, while avoiding optical path occlusion or mechanical interference, and facilitating the unified design of the layout of the conductive contacts. There is no need to design complex contact structures for the positive and negative electrodes of the laser respectively, improving the compatibility of the laser polarization degree test device.

[0023] Of course, a double-sided wire bonding transfer structure can also be used. For example, the negative electrode of the laser is connected to the negative electrode solder joint on the second surface of the thin film circuit 2 by wire bonding with a gold wire. The negative electrode solder joint extends to the edge of the thin film circuit 2 through a first metal trace and is connected to the negative electrode contact on the first surface of the thin film circuit 2 by side wire bonding; or an embedded bump transfer structure can be used. For example, the negative electrode of the laser is connected to the negative electrode bump on the second surface of the thin film circuit 2 by Au-Sn eutectic soldering. The negative electrode bump is an embedded structure, and its bottom is directly connected to the negative electrode contact on the first surface through a conductive column penetrating the thin film circuit 2, etc. All of them can realize the connection of the laser electrodes and supply power to the electrodes of the laser.

[0024] Optionally, the device further includes a nylon support structure 4 fixedly arranged between the rotating table 5 and the laser limiting device 3.

[0025] In this embodiment, the nylon support structure 4 is fixedly connected between the laser limiting device 3 and the rotating table 5, and can form a mechanical support and thermal isolation layer. Ensure that the relative position of the rotating table 5 and the laser limiting device 3 is stable, maintain the coaxiality of the optical path system, and block the heat transfer from the laser limiting device 3 to the rotating table 5, so as to avoid the temperature change from affecting the performance of the polarizer and the photodiode 6. The specific structure and form of the nylon support structure 4 are not specifically limited in the embodiment of the present application. The specific number and specification of nylon pillars can be selected according to the specific environment, and evenly distributed on the edges of the rotating table 5 and the laser limiting device 3. Of course, other distribution methods can also be used; an integral nylon pad can also be used, with a positioning groove on the upper surface to cooperate with the rotating table 5, and a screw hole on the lower surface to fix with the laser limiting device 3. Different forms of nylon support structures 4 do not affect the realization of the basic functions of the laser polarization test device in the embodiment of the present application.

[0026] In this embodiment, the nylon support structure 4 plays a role in mechanical support, thermal isolation, electromagnetic compatibility, etc. through the coordination of material selection and structural design, thereby improving the stability of the optical path system and the controllability of the temperature environment in the laser polarization test.

[0027] In addition, a polyetheretherketone support structure can also be used, which is in the shape of a hollow cylinder, and the upper and lower end faces are fixed to the bottom surface of the rotating table 5 and the top surface of the laser limiting device 3 respectively by countersunk screws; the outer diameter of the polyetheretherketone support structure is aligned with the edge of the rotating table 5, and the inner diameter is larger than the light output aperture of the laser, and the upper and lower end faces can be pre-embedded with metal inserts and fixed by stainless steel screws. A black matte coating can be sprayed on the inner surface of the support structure to reduce the interference of stray light reflection on the photodiode 6. A ceramic air-floating support structure can also be used, which is evenly distributed between the rotating table 5 and the laser limiting device 3; a hemispherical air-floating bearing is set at the top of each ceramic pillar, and a flat air-floating pad is set at the bottom to achieve contactless support of the rotating table 5. Or not adding an additional support structure does not affect the realization of the basic functions of the laser polarization test device in the embodiment of the present application.

[0028] Optionally, the conductive contact is a spring probe, the supporting structure is a plastic top plate, and the spring probe penetrates through and is fixedly connected to the plastic top plate.

[0029] In this embodiment, the probe body can be made of beryllium copper (BeCu) or phosphor bronze (CuSn). In some optional embodiments, the surface can also be gold-plated to ensure low resistance and corrosion resistance; the internal spring can be made of stainless steel or nickel alloy, and the tip of the probe can be designed in a conical or wedge shape. When the plastic top plate is pressed down, the spring probe contacts the electrode contact and compresses, and the elastic force generated by the spring ensures stable contact. The compressible nature of the probe compensates for processing tolerances and surface unevenness.

[0030] The above-mentioned plastic top plate is lighter than the metal top plate, which reduces the load on the driving mechanism and increases the moving speed. The non-metallic material avoids the electromagnetic shielding effect caused by the metal structure and reduces the interference with the weak photocurrent signal. Due to the dynamic compensation mechanism of the spring probe, the contact resistance fluctuation can be reduced and the stability of the electrical connection is improved. The plug-in life of the spring probe is also higher than that of the traditional rigid probe, which reduces the maintenance cost of frequent replacement of the probe to a certain extent. In some optional embodiments, the plastic top plate can be provided with a stepped hole, and the probe is fixed by an interference fit.

[0031] In this implementation, the contact reliability and electromagnetic compatibility issues are solved by combining the spring probe with the plastic top plate, thereby improving the adaptability of the laser polarization test device to the test scenarios of high-precision, small-size lasers. To a certain extent, the reliability of the electrical connection of the laser electrodes is also improved, the stability of the laser power supply is improved, and the test accuracy of the laser polarization is further improved.

[0032] In addition, a cantilever beam elastic probe can also be used, and a printed circuit board PCB is used as a supporting structure. The cantilever beam elastic probe is connected to the internal wiring of the PCB through a metallized via, and the probe array is integrally formed with the pad on the surface of the PCB. A tungsten needle tip can also be used as a conductive contact, fixed to the moving end of the piezoelectric ceramic driver, and the supporting structure is an alumina ceramic substrate, which integrates a piezoelectric drive circuit and a signal conditioning circuit; the piezoelectric driver has a built-in strain gauge sensor to form a force feedback closed-loop control, and the piezoelectric ceramic driver realizes the displacement of the conductive component 1 through closed-loop control. The selection of different forms of conductive components 1 and supporting structures does not affect the realization of the basic functions of the laser polarization test device in the embodiment of the present application.

[0033] Optionally, the laser limiting device 3 is made of metal material, and a heating resistance wire is fixedly arranged at the bottom of the slot.

[0034] The above-mentioned metal materials can be aluminum alloy, copper alloy or other metal materials. In this regard, the embodiments of the present invention do not make specific limitations. Metal materials with high thermal conductivity can be used to quickly and evenly conduct the heat generated by the heating resistance wire to the card slot area; in some alternative embodiments, the laser limiting device 3 is a metal material fixing card slot, carrying the thin film circuit 2, and cooperating with the nylon support structure 4 to form a "heating-insulation" temperature control unit. A heating resistance wire is fixedly arranged at the bottom of the above-mentioned card slot. The resistance wire can be closely attached to the inner wall of the bottom of the card slot, or can be arranged in a serpentine or grid pattern. The specific material of the resistance wire is also not limited in the embodiments of the present application. Heat-resistant and oxidation-resistant entering materials such as nickel-chromium alloy can be used. In some alternative embodiments, it can be pasted on the bottom of the card slot through a high-temperature resistant adhesive such as silicone resin, or embedded in a metal groove to avoid local overheating caused by displacement.

[0035] Exemplarily, the power supply module of the controller 7 applies a voltage to the heating resistance wire to generate Joule heat. The polarization degree of the VCSEL laser can change with temperature. By stabilizing the test temperature at the target value through the heating resistance wire, the influence of temperature fluctuation on the measurement result can be eliminated. In addition, after heating, the thermal expansion consistency of the thin film circuit 2 and the card slot reduces the contact gap, and with the elastic compensation of the spring probe, the connection stability between the conductive contact and the electrode contact at high temperature can be enhanced.

[0036] In this embodiment, the metal material of the laser limiting device 3 and the heating resistance wire at the bottom of the card slot provide a stable temperature test environment for the laser through efficient heat conduction and temperature control, improving the accuracy and repeatability of polarization degree measurement under different temperature conditions.

[0037] In addition, rectangular grooves with uniform distribution can be opened at the bottom of the above-mentioned card slot, and each groove is embedded with a multilayer ceramic heating sheet with independent control. The heating sheet is fixed through thermal conductive silicone. The bottom of the card slot can also be designed as a mirror reflection surface. The heating system includes an infrared LED array located below the device, and the infrared light is focused on the card slot area through a parabolic reflector. At the same time, an infrared absorption coating is attached to the bottom of the above-mentioned thin film circuit 2 to achieve non-contact heating. Different heating methods do not affect the realization of the basic functions of the laser polarization degree test device in the embodiments of the present application.

[0038] Optionally, the photodiode 6 is fixed by a pillar, and the position of the photodiode 6 is in the light output direction of the polarizer.

[0039] The present application embodiment does not specifically limit the shape, size, and specific material of the support pillar. In some alternative embodiments, surface treatment can be performed on the support structure, such as black anodizing or electroless nickel plating, etc., which can reduce stray light reflection. In some alternative embodiments, the bottom of the above-mentioned support pillar can be rigidly connected to the device base through threaded holes, and the top can fix the photodiode 6 through an elastic clamping seat. A three-dimensional adjustment mechanism, such as a ball hinge and a locking nut, can also be provided at the top of the support pillar to achieve coaxial calibration of the photosensitive surface of the photodiode 6 and the axis of the rotating table 5. The above-mentioned photodiode 6 can also be attached to the top of the support pillar through thermal conductive silicone, and at the same time, a radial force is applied by a stainless steel clamp to avoid loosening to a certain extent; the support pillar fixing structure combines material selection and mechanical design to improve the positioning accuracy and stability of the photodiode 6 in a complex environment to a certain extent, and improves the accuracy of optical signal acquisition.

[0040] In addition, the photodiode 6 can also be fixed by an integrally processed aluminum alloy flexible hinge cantilever. The cantilever consists of a rigid section at the root, a flexible bending section in the middle, and an end mounting platform; the photodiode 6 can also be installed on a permanent magnet base, and the permanent magnet and the electromagnet array on the device base form a magnetic levitation support. When the power is off, a mechanical locking mechanism is triggered to ensure that the photodiode 6 lands smoothly in the protection groove to avoid collision damage.

[0041] Optionally, the controller 7 includes a power supply module, a rotation control module, a data acquisition module, and a calculation module; The power supply module is electrically connected to the conductive component 1 through a first wire for supplying power to the conductive component 1; the rotation control module is electrically connected to the drive motor of the rotating table 5 through a second wire for driving the rotating table 5 to rotate; the data acquisition module is electrically connected to the photodiode 6 through a third wire. The data acquisition module includes a preamplifier and an analog-to-digital converter; the calculation module is connected to the power supply module, the rotation control module, and the data acquisition module respectively through an internal bus for calculating the polarization degree of the laser.

[0042] In this embodiment, the controller 7 can form a closed-loop circuit with the conductive component 1 through the first wire and adopt a constant current source or constant voltage source power supply mode. In some alternative embodiments, a filter circuit can be built in to suppress the influence of high-frequency interference on the laser polarization state. Connect the servo motor of the rotating table 5 through the second wire to drive the polarizer to rotate at a fixed angular velocity, and cooperate with the photodiode 6 to synchronously collect the light intensity signal to construct a light intensity - angle relationship curve.

[0043] The above data acquisition module can serve as a conversion bridge for optoelectronic signals. The preamplifier can adopt a low-noise design to adapt to the current output of the photodiode 6. In some alternative embodiments, the above third wire can adopt a twisted shielded wire, and an RC filter circuit can be provided at the input end to suppress ambient light noise and power frequency interference.

[0044] The above calculation module can be understood as the intelligent core for polarization degree calculation. It reads three parts of data in real time through the internal bus, which can include the output voltage or current of the power supply module, the real-time angle of the rotation control module, and the digitized light intensity signal of the data acquisition module, etc.

[0045] Exemplarily, the power supply module is started to supply power to the laser in a constant current mode. The rotation control module drives the polarizer to zero. The photodiode 6 collects the initial light intensity. The turntable 5 rotates step by step at a preset angular velocity. Every time an angle point is reached, a synchronous acquisition of the light intensity signal is triggered. The calculation module collects and calculates the polarization degree in real time. In some alternative embodiments, if the result exceeds the set threshold, a secondary scan can be automatically triggered. The polarization degree value and curve can be displayed through a human-machine interface, such as a touch screen. At the same time, the data can be stored in the built-in memory. In this embodiment, through modular design, the controller 7 realizes the deep integration of power supply, motion control, signal acquisition, and data processing, which not only improves the measurement accuracy but also enhances the system scalability through a standardized interface.

[0046] In addition, other unit modules can also be expanded in the controller 7, or a certain module above can be reduced and controlled independently of the controller 7. In this regard, the embodiments of the present application do not make specific limitations.

[0047] Optionally, elastic limiting protrusions are provided on the inner wall of the card slot.

[0048] In this embodiment, for the specific material of the above elastic limiting protrusions, the embodiments of the present application do not make specific limitations. It can be silica gel, thermoplastic elastomer, or nylon plus elastic fiber, etc. When the above thin film circuit 2 is inserted into the card slot, the protrusions are elastically deformed under extrusion, generating a radial restoring force, which can hold the thin film circuit 2 to prevent axial movement. In some alternative embodiments, the surface of the protrusions can be designed to be serrated to increase the friction coefficient and improve the anti-vibration performance. In addition, a buckle or a guiding groove, etc. can also be used to replace the elastic limiting protrusions to achieve the limiting effect on the thin film circuit 2.

[0049] In this embodiment, by providing elastic limiting protrusions on the inner wall of the card slot, thin film circuits 2 of different batches can be stably installed, improving the positioning accuracy. The flexible material can avoid scratching the edges of the thin film circuit 2 caused by rigid contact to a certain extent. In addition, no additional fasteners are required and the installation can be completed through blind insertion, reducing the test time and improving the test efficiency.

[0050] Optionally, the lower end face of the conductive contact is a gold-plated hemispherical surface.

[0051] In this embodiment, the oxidation resistance and low contact resistance of the gold plating layer ensure long-term conduction reliability, especially suitable for high-frequency signal transmission, thereby reducing signal loss. The hemispherical curvature can allow insertion angle deviation and position tolerance, thus reducing the requirement for mechanical assembly accuracy, and being more adaptable to the automated blind insertion scenario. In addition, the wear volume of spherical contact is relatively less than that of planar contact, and it can cooperate with elastic structures such as spring probes to improve the plugging and unplugging life.

[0052] Of course, the lower end face of the conductive contact can also be selected with other shapes and materials according to requirements, such as silver-plated convex platform type or conductive rubber elastic contacts, etc.; in this regard, the embodiments of the present application do not make specific limitations.

[0053] Optionally, a temperature sensor is further provided at the bottom of the card slot, the controller 7 is electrically connected to the temperature sensor, and the controller 7 collects the temperature data of the card slot in real time and adjusts the power of the heating resistance wire according to a preset temperature threshold.

[0054] In the embodiments of the present application, since a temperature sensor is further provided at the bottom of the card slot, precise control of the temperature of the card slot can be achieved through a closed-loop feedback mechanism. A temperature sensor is directly installed at the bottom of the slot, such as a thermocouple, platinum resistance or thermistor, etc., closely attached to the mounting surface of the object to be measured. The above temperature sensor can transmit the analog signal to the analog-to-digital conversion module of the controller 7 through a shielded cable. In some optional embodiments, the controller 7 can preset the upper and lower temperature limits. When the measured temperature is not within the preset range, the resistance wire heating is triggered or the heating power of the resistance wire is reduced or cut off. For the control method of the resistance wire, the embodiments of the present application do not make specific limitations. The power can be adjusted steplessly by changing the duty cycle of the heating resistance wire, or a proportional-integral-derivative algorithm can be introduced to dynamically adjust the heating power.

[0055] In addition, a thermoelectric cooler temperature control system or a fluid circulation temperature control system, etc. can also be adopted. Different temperature control methods do not affect the realization of the basic functions of the embodiments of the present application.

[0056] In this embodiment, through the real-time feedback of the temperature sensor, a temperature closed-loop control is realized, which improves the test efficiency while ensuring the reliability of the equipment, and is especially suitable for the scenario of precision instruments sensitive to temperature.

[0057] In the embodiment of the present application, since it includes a thin-film circuit, an electrode contact of a laser is provided on the first surface of the thin-film circuit; a laser limiting device, which has a card slot for fixedly placing the thin-film circuit on a bearing surface; a conductive component, the position of the conductive component is in the direction close to the bearing surface of the laser limiting device, the conductive component includes a support structure that can move up and down along a guide rail perpendicular to the bearing surface and at least two conductive contacts, the conductive contacts are fixed to the support structure and are vertically corresponding to the positions of the electrode contacts, when testing the polarization degree of the laser, the conductive component moves in the direction close to the card slot, so that the conductive contacts are in contact with the electrode contacts and form an electrical connection; a rotary table, a through hole is opened at the axis of the rotary table, and a polarizer is fixedly arranged on the receiving surface of the rotary table; a photodiode, the photodiode is vertically arranged in the light-emitting direction of the polarizer, and the photosensitive surface of the photodiode is coaxial with the rotary table; a controller, the controller is electrically connected to the conductive component, the rotary table and the photodiode through wires respectively, and the controller is used to control the rotation of the rotary table, supply power to the conductive component, collect the output signal of the photodiode and calculate the polarization degree of the laser. In the embodiment of the present application, the card slot of the laser limiting device accurately positions the thin-film circuit, and cooperates with the vertically movable conductive contacts to achieve reliable contact and electrical connection of the microelectrodes, which can reduce the unstable contact during the test of small-size devices. The coaxial layout of the through hole at the axis of the rotary table, the polarizer and the photodiode ensures that the laser beam is vertically incident on the photosensitive surface, reduces the optical path offset error, and improves the optical signal acquisition accuracy. In addition, the controllable movement of the conductive component along the vertical guide rail is compatible with the electrode layouts of different specifications of lasers, enhances the versatility and operation convenience of the device, and thus improves the test efficiency of the polarization degrees of different specifications of lasers.

[0058] The above description is only the preferred embodiment of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

[0059] Except for the technical features described in the specification, the rest of the technical features are well-known technologies to those skilled in the art. To highlight the innovative features of the present invention, the rest of the technical features will not be described in detail here.

Claims

1. A laser polarization degree testing device, characterized in that, The device includes: A thin-film circuit, on the first surface of which there are electrode contacts of a laser; A laser limiting device, which has a card slot for fixedly placing the thin-film circuit on a bearing surface; A conductive component, which is arranged in the direction close to the bearing surface of the laser limiting device. The conductive component includes a support structure that can move up and down along a guide rail perpendicular to the bearing surface and at least two conductive contacts. The conductive contacts are fixed to the support structure and are vertically corresponding to the electrode contacts. When testing the polarization degree of the laser, the conductive component moves in the direction close to the card slot, so that the conductive contacts contact the electrode contacts and form an electrical connection; A rotating table, with a through hole opened at the axis of the rotating table, and a polarizer is fixedly arranged on the receiving surface of the rotating table; A photodiode, which is vertically arranged in the light-emitting direction of the polarizer, and the photosensitive surface of the photodiode is coaxial with the rotating table; A controller, which is electrically connected to the conductive component, the rotating table and the photodiode through wires respectively. The controller is used to control the rotation of the rotating table, supply power to the conductive component, collect the output signal of the photodiode and calculate the polarization degree of the laser; 2. The device according to claim 1, characterized in that, The negative electrode of the laser is welded to the second surface of the thin-film circuit and is connected to the negative electrode contact of the electrode contact through a first through hole. The positive electrode of the laser is transferred to the positive electrode solder joint on the second surface by wire bonding and is connected to the positive electrode contact of the electrode contact through a second through hole; 3. The device according to claim 2, wherein The device also includes a nylon support structure fixedly arranged between the rotating table and the laser limiting device; 4. The device according to any one of claims 1 to 3, characterized in that, The conductive contact is a spring probe, and the support structure is a plastic top plate. The spring probe penetrates and is fixedly connected to the plastic top plate; 5. The device according to any one of claims 1 to 3, characterized in that The laser limiting device is made of a metal material, and a heating resistance wire is fixedly arranged at the bottom of the card slot; 6. The device according to any one of claims 1 to 3, characterized in that, The photodiode is fixed by a support column, and the position of the photodiode is in the light-emitting direction of the polarizer; 7. The device according to any one of claims 1 to 3, characterized in that, The controller includes a power supply module, a rotation control module, a data acquisition module and a calculation module; The power supply module is electrically connected to the conductive component through a first wire for supplying power to the conductive component; The rotation control module is electrically connected to the drive motor of the rotating table through a second wire for driving the rotation of the rotating table. The data acquisition module is electrically connected to the photodiode through a third wire. The data acquisition module includes a preamplifier and an analog-to-digital converter; The calculation module is connected to the power supply module, the rotation control module and the data acquisition module through an internal bus respectively for calculating the polarization degree of the laser; 8. The device according to any one of claims 1 to 3, characterized in that, Elastic limiting protrusions are arranged on the inner wall of the card slot; 9. The device according to any one of claims 1 to 3, characterized in that, The lower end surface of the conductive contact is a gold-plated hemispherical surface; 10. The device according to claim 5, characterized in that, A temperature sensor is also arranged at the bottom of the card slot. The controller is electrically connected to the temperature sensor. The controller collects the temperature data of the card slot in real time and adjusts the power of the heating resistance wire according to a preset temperature threshold.

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