Debugging method for fast optical fiber delay line

Abstract

The invention provides a debugging method for a fast optical fiber delay line, which comprises the following steps of: searching a driving shaft of a translation platform of a positioning motor as a main optical axis, converting the main optical axis by using a theodolite and a visible light laser, then adjusting two optical fiber collimating mirrors to enable the optical axes of the two optical fiber collimating mirrors to be parallel to the main optical axis, and adjusting the positions of two movable pyramid reflectors to realize debugging of the fast optical fiber delay line. It is ensured that the visible laser thin beam can sequentially pass through the reflectors and finally be emitted out of the other optical fiber collimating mirror. And finally, the optical fiber collimating mirror is finely adjusted to maximize the coupling efficiency average value of the optical fiber delay line and minimize the change rate of the optical fiber delay line, so that the coupling efficiency change of the optical fiber delay line is effectively controlled in the moving process of the translation stage, and the measurement precision of the terahertz time-domain spectrometer and the optical frequency comb is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber delay line debugging, and in particular to a debugging method for a fast optical fiber delay line. Background Art

[0002] Fast fiber delay lines are widely used in terahertz time-domain spectrometers and optical frequency combs, and are one of the core components of terahertz time-domain spectrometers and optical frequency combs. They are mainly composed of fixed corner reflectors, mobile corner reflectors, motor translation stages, and fiber collimators. The mobile corner reflector is fixed on the motor translation stage and can move back and forth with the motor translation stage. Fast fiber delay lines are the key to ensuring the measurement accuracy of terahertz time-domain spectrometers. If the coupling efficiency of the fast fiber delay line is poor, or the coupling efficiency of the fiber delay line changes dramatically or even suddenly during the movement of the motor translation stage, the signal-to-noise ratio and spectral resolution of the terahertz time-domain spectrometer will be greatly reduced.

[0003] In the prior art, in order to control the coupling efficiency and change rate of the fast optical fiber delay line during the debugging process, it is necessary to adjust the motor translation stage drive axis and the optical axis to be parallel. Since it is impossible to accurately locate the drive axis of the motor translation stage, the debugging process can only be carried out by regularly adjusting the optical axis direction over a large range to find the direction of the optical axis parallel to the drive axis of the motor translation stage. The entire debugging process is time-consuming and labor-intensive, the debugging efficiency is low, and it is easy to be out of adjustment. Therefore, there is an urgent need for a method that can quickly and efficiently complete the debugging of fast optical fiber delay lines. Summary of the invention

[0004] The embodiment of the present invention solves the technical problem of low efficiency of optical fiber delay lines in the prior art by providing a debugging method for a fast optical fiber delay line.

[0005] In the first aspect, to solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] A method for fast optical fiber delay line debugging, comprising:

[0007] The invention comprises a focusing autocollimator, a spherical reflector, a debugging platform, a base arranged on the debugging platform, a motor translation platform slidably connected to the base, a first mounting plate detachably connected to the motor translation platform, two movable corner cube reflectors connected to the first mounting plate, a second mounting plate detachably connected to the end of the base, and a fixed corner cube reflector connected to the second mounting plate; the movable corner cube reflector and the fixed corner cube reflector both comprise three reflecting surfaces, and the three reflecting surfaces are vertical and concave inwards;

[0008] The method includes:

[0009] S1, arranging an inner focusing autocollimator and a spherical reflector according to a preset position, wherein the preset position satisfies that the spherical reflector is arranged on a motor translation stage, the reflective surface of the spherical reflector faces the inner focusing autocollimator, the center height of the spherical reflector is the same as the center height of the optical fiber delay line, and the central optical axis of the spherical reflector is collinear with the central optical axis of the inner focusing autocollimator; and the driving axis direction of the motor translation stage is taken as the direction of the main optical axis;

[0010] Turn on the inner focusing autocollimator and the motor translation stage in sequence, control the motor translation stage to be in multiple positions, adjust the focal length of the inner focusing autocollimator and the orientation and posture of the debugging stage at each position, so that the autocollimator cross image emitted by the inner focusing autocollimator and reflected back by the spherical reflector coincides with the standard cross image; remove the spherical reflector;

[0011] S2, arrange the theodolite so that the center height of the theodolite is the same as the center height of the optical fiber delay line, and the theodolite faces the inner focusing autocollimator; install a second mounting plate and two optical fiber collimators symmetrical along the center line of the second mounting plate on the base; connect the optical fiber collimators to the optical fiber attenuator and the visible light laser in sequence, and adjust the position of the theodolite so that the parallel thin light beams emitted by the two optical fiber collimators can be received by the theodolite; then turn off the visible light laser, remove the second mounting plate and the optical fiber collimators, and make the parallel light beams emitted by the inner focusing autocollimator incident on the theodolite; adjust the azimuth and posture of the theodolite so that the cross image of the inner focusing autocollimator and the cross image inside the theodolite overlap;

[0012] S3, installing the second mounting plate on the base, and adjusting the two fiber optic collimators on the second mounting plate so that the optical axes of the two fiber optic collimators are parallel to the main optical axis respectively;

[0013] S4, installing the first mounting plate on the motor translation stage, connecting the fiber collimator to the fiber attenuator and the visible light laser in sequence, adjusting the first mounting plate so that the light beam emitted by the visible light laser passes through the fiber attenuator, a fiber collimator, a movable corner reflector, a fixed corner reflector, another movable corner reflector and another fiber collimator in sequence; fixing the position of the first mounting plate at this moment;

[0014] S5, replace the visible light laser with a test laser. The wavelength of the test laser should be the same as the working wavelength of the optical fiber delay line; connect the optical fiber power meter to the optical fiber collimator that emits the light beam, and measure the first laser power value input to the optical fiber collimator and the second laser power value output from the optical fiber collimator by adjusting the optical fiber attenuator, respectively, and calculate the coupling efficiency of the optical fiber delay line according to the first laser power value and the second laser power value; control the motor translation stage to move from an initial zero position to a maximum stroke, record the maximum coupling efficiency and minimum coupling efficiency of the optical fiber delay line during the movement of the motor translation stage, and calculate the change rate and average value of the coupling efficiency of the optical fiber delay line based on the maximum coupling efficiency and the minimum coupling efficiency; adjust the orientation and posture of the two optical fiber collimators respectively until the average value of the coupling efficiency of the optical fiber delay line is maximized and the change rate of the coupling efficiency of the optical fiber delay line is minimized.

[0015] Optionally, the step of arranging the inner focusing autocollimator and the spherical reflector according to preset positions specifically includes:

[0016] Measure and record the center height of the fixed retroreflector as the center height of the optical fiber delay line;

[0017] Adjust the inner focusing autocollimator so that the center height of the inner focusing autocollimator is the same as the center height of the optical fiber delay line, and the inner focusing autocollimator faces the moving corner reflector; adjust the center optical axis of the inner focusing autocollimator to be parallel to the driving axis of the motor translation stage, and adjust the center optical axis of the inner focusing autocollimator to align with the center of the fixed corner reflector;

[0018] Remove the second mounting plate and the first mounting plate;

[0019] A spherical reflector is installed on the motor translation stage so that the reflective surface of the spherical reflector faces the inner focusing autocollimator, and the center height of the spherical reflector is the same as the center height of the optical fiber delay line, and the center optical axis of the spherical reflector is collinear with the center optical axis of the inner focusing autocollimator.

[0020] Optionally, the step of adjusting the orientation and posture of the theodolite so that the cross image of the internal focusing autocollimator coincides with the cross image inside the theodolite specifically includes:

[0021] The focal length of the internal focusing autocollimator is adjusted so that the working distance of the internal focusing autocollimator is infinite. The parallel light beam emitted by the internal focusing autocollimator is incident on the theodolite. The azimuth attitude of the theodolite is adjusted so that the cross image of the internal focusing autocollimator and the cross image inside the theodolite coincide with each other.

[0022] Optionally, until the average value of the coupling efficiency of the optical fiber delay line is the largest and the change rate of the coupling efficiency of the optical fiber delay line is the smallest, the method further includes:

[0023] Fix the two optical fiber collimators on the second mounting plate respectively by gluing;

[0024] Before the glue solidifies, monitor the optical fiber delay line coupling efficiency and the rate of change of the optical fiber delay line coupling efficiency at preset time intervals. If either one changes, adjust the corresponding optical fiber collimator until the average value of the optical fiber delay line coupling efficiency is maximized and the rate of change of the optical fiber delay line coupling efficiency is minimized.

[0025] In a second aspect, a debugging platform is provided, which is applied to the steps corresponding to the method in the first aspect, including:

[0026] The debugging platform includes: a connecting plate, a connecting rod, a universal joint, a first telescopic part, a second telescopic part, a first bolt and a second bolt. The connecting plate is connected to the universal joint through the connecting rod. The universal joint is arranged at the end of the first telescopic part. The first bolt passes through the first telescopic part and abuts against the universal joint to constrain the rotation of the universal joint. The second telescopic part is sleeved on the first telescopic part and is slidably connected to the first telescopic part. The second bolt passes through the second telescopic part and abuts against the first telescopic part to constrain the movement of the first telescopic part.

[0027] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0028] The present invention finds the driving axis of the positioning motor translation stage as the main optical axis, uses the theodolite and the visible light laser to convert the main optical axis, then adjusts the two fiber collimators to make their optical axes parallel to the main optical axis, and adjusts the positions of the two moving corner cube reflectors to ensure that the visible laser beam can pass through these reflectors in sequence and finally be emitted from the other fiber collimator. Finally, the fiber collimator is fine-tuned to maximize the average coupling efficiency of the fiber delay line and minimize its change rate, so as to effectively control the change of the coupling efficiency of the fiber delay line during the movement of the translation stage and ensure the measurement accuracy of the terahertz time-domain spectrometer and the optical frequency comb. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A fast optical fiber delay line debugging schematic diagram of a debugging method for a fast optical fiber delay line provided by the present invention;

[0031] Figure 2 A schematic diagram of finding the driving axis of the motor translation stage in the present invention;

[0032] Figure 3A schematic diagram of converting the driving axis of the motor translation stage into the main optical axis in the present invention;

[0033] Figure 4 It is a schematic diagram of the arrangement of theodolite in the present invention;

[0034] Figure 5 This is a schematic diagram of adjusting two optical fiber collimators in the present invention so that their optical axes are parallel to the main optical axis respectively;

[0035] Figure 6 A schematic diagram of using visible light laser to adjust two movable corner reflectors in the present invention;

[0036] Figure 7 A schematic diagram of fine-tuning two optical fiber collimators using a test laser in the present invention;

[0037] Figure 8 The present invention provides a schematic structural diagram of a debugging platform.

[0038] Figure numerals: 1. internal focusing autocollimator; 2. base; 21. motor translation stage; 22. first mounting plate; 23. movable corner cone reflector; 24. fiber optic collimator; 25. second mounting plate; 26. fixed corner cone reflector; 3. spherical reflector; 4. theodolite; 5. test laser; 6. fiber optic power meter; 7. visible light laser; 8. fiber optic attenuator; 9. debugging platform; 91. connecting plate; 92. connecting rod; 93. universal joint; 94. first telescopic member; 95. second telescopic member; 96. second bolt; 97. first bolt. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, in the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0042] In an embodiment of the present invention, there is provided Figure 1 A method for fast optical fiber delay line debugging is shown, the method comprising steps S1 to S5:

[0043] like Figure 1 As shown, it includes a focusing autocollimator, a spherical reflector 3, a debugging platform, a base 2 arranged on the debugging platform, a motor translation platform 21 slidably connected to the base 2, a first mounting plate 22 detachably connected to the motor translation platform 21, two movable corner-reflecting mirrors 23 connected to the first mounting plate 22, a second mounting plate 25 detachably connected to the end of the base 2, and a fixed corner-reflecting mirror 26 connected to the second mounting plate 25; the movable corner-reflecting mirror 23 and the fixed corner-reflecting mirror 26 each include three reflecting surfaces, and the three reflecting surfaces are vertical and concave inwards;

[0044] The method comprises:

[0045] S1, arrange the inner focusing autocollimator 1 and the spherical reflector 3 according to the preset position, the preset position satisfies that the spherical reflector 3 is arranged on the motor translation stage 21, the reflection surface of the spherical reflector 3 faces the inner focusing autocollimator 1, the center height of the spherical reflector 3 is the same as the center height of the optical fiber delay line, and the central optical axis of the spherical reflector 3 is collinear with the central optical axis of the inner focusing autocollimator 1; the driving axis direction of the motor translation stage 21 is taken as the direction of the main optical axis;

[0046] Specifically, Figure 2 As shown, the fixed corner reflector 26 is fixed in the preset mounting hole position on the second mounting plate 25 by gluing. At the same time, the two movable corner reflectors 23 are respectively installed on the corresponding mounting holes of the first mounting plate 22. Next, the pre-installation step is performed: the second mounting plate 25 with the fixed corner reflector 26 installed is assembled to the base 2; then, the motor translation stage 21 is installed on the base 2 of the fast optical fiber delay line, and the first mounting plate 22 and the movable corner reflector 23 thereon are pre-assembled on the motor translation stage 21. At this time, ensure that the reflective surfaces of the movable corner reflector 23 and the fixed corner reflector 26 are aligned with each other. Finally, the measurement work is performed, specifically, the center height of the fixed corner reflector 26 is measured and recorded.

[0047] The inner focusing autocollimator 1 is adjusted to ensure that its center height is consistent with the center height of the optical fiber delay line, and the front of the inner focusing autocollimator 1 faces the moving corner reflector 23. Next, the central optical axis of the inner focusing autocollimator 1 is further adjusted to be parallel to the driving axis of the motor translation stage 21 and accurately aligned with the center position of the fixed corner reflector 26. After completing these preliminary calibration steps, the second mounting plate 25 and the first mounting plate 22 are removed next.

[0048] Then, the spherical reflector 3 is installed on the motor translation stage 21. During installation, it is necessary to ensure that the reflective surface of the spherical reflector 3 faces the inner focusing autocollimator 1, and the center height of the spherical reflector 3 is kept the same as the center height of the optical fiber delay line. In addition, it is necessary to ensure that the central optical axis of the spherical reflector 3 is in a collinear state with the central optical axis of the inner focusing autocollimator 1, so as to complete the arrangement of the inner focusing autocollimator 1 and the spherical reflector 3.

[0049] Among them, the motor translation platform 21 includes a platform, a driving motor, a screw rod (i.e., a driving shaft) arranged on the base 2, and a slider threadedly connected to the screw rod. The platform is fixedly connected to the slider, and the end of the screw rod is fixedly connected to the output shaft of the driving motor; the screw rod is driven to rotate by the driving motor, thereby driving the platform to move along the screw rod.

[0050] Turn on the inner focusing autocollimator 1 and the motor translation stage 21 in sequence, control the motor translation stage 21 to be in multiple positions, adjust the focal length of the inner focusing autocollimator 1 and the orientation and posture of the debugging stage at each position, so that the autocollimator cross image emitted by the inner focusing autocollimator 1 and reflected back by the spherical reflector 3 coincides with the standard cross image; remove the spherical reflector 3;

[0051] Specifically, the control of the motor translation stage 21 is first controlled to its initial zero position. Next, the focal length of the internal focusing autocollimator 1 is adjusted, and the azimuth and pitch angle of the debugging platform are preliminarily adjusted. The purpose of this step is to ensure that the autocollimation cross image reflected back by the spherical reflector 3 can be clearly imaged within the field of view of the internal focusing autocollimator 1. After the coarse adjustment is completed, the focal length of the internal focusing autocollimator 1 is fixed, and the azimuth and pitch attitude of the debugging platform are further fine-tuned until the autocollimation cross image displayed by the internal focusing autocollimator 1 completely coincides with the fixed cross image inside it, which indicates the completion of the preliminary calibration.

[0052] Next, move the motor translation stage 21 to its maximum travel position. Adjust the focal length of the internal focusing autocollimator 1 again to ensure that the autocollimation cross image reflected by the spherical reflector 3 can still be clearly imaged in the field of view. At this time, carefully observe whether the autocollimation cross image of the internal focusing autocollimator 1 still coincides with its internal cross image. If the two coincide, it indicates that the drive shaft of the motor translation stage 21 has been successfully found and positioned, and the entire calibration process is now complete.

[0053] S2, arrange theodolite 4, such as Figure 3 As shown, the center height of the theodolite 4 is made equal to the center height of the optical fiber delay line, and the theodolite 4 faces the inner focusing autocollimator 1; a second mounting plate 25 and two optical fiber collimators 24 symmetrical along the center line of the second mounting plate 25 are mounted on the base 2; the optical fiber collimators 24 are connected to the optical fiber attenuator 8 and the visible light laser 7 in sequence, and the position of the theodolite 4 is adjusted so that the parallel thin light beams emitted by the two optical fiber collimators 24 can be received by the theodolite 4; then the visible light laser 7 is turned off, the second mounting plate 25 and the optical fiber collimators 24 are removed, and the parallel light beams emitted by the inner focusing autocollimator 1 are incident on the theodolite 4; the azimuth and posture of the theodolite 4 are adjusted so that the cross image of the inner focusing autocollimator 1 and the cross image inside the theodolite 4 coincide with each other;

[0054] Among them, for the adjustment of theodolite 4, Figure 4 As shown, specifically: adjust the focal length of the inner focusing autocollimator 1 so that the working distance of the inner focusing autocollimator 1 is infinite, the parallel light beam emitted by the inner focusing autocollimator 1 is incident on the theodolite 4, and adjust the azimuth posture of the theodolite 4 so that the cross image of the inner focusing autocollimator 1 and the cross image inside the theodolite 4 coincide with each other.

[0055] S3, installing the second mounting plate 25 on the base 2, and adjusting the two fiber collimators 24 on the second mounting plate 25 so that the optical axes of the two fiber collimators 24 are parallel to the main optical axis.

[0056] Specifically, Figure 5 As shown, during the adjustment process, the two fiber collimators 24 ensure that their optical axes remain parallel to the main optical axis. To achieve this goal, a second mounting plate 25 is installed on the base 2 of the fiber delay line, and holes for mounting the fiber collimators 24 are pre-set on the plate. Next, the two fiber collimators 24 are clamped by a mechanical arm, and their positions and postures are adjusted through fine manipulation of the mechanical arm to ensure that the fiber collimators 24 are facing the theodolite 4. Observing from the opposite direction of the light beam transmission, the mechanical arm is further adjusted until the center of the end face of the fiber collimator 24 roughly coincides with the center of the circle of the corresponding mounting hole.

[0057] Subsequently, the visible light laser 7 is started again, and the laser outputted by the visible light laser 7 is first attenuated by the adjustable fiber attenuator 8, and then introduced into the fiber collimator 24 through the optical fiber. The adjustable fiber attenuator 8 is adjusted to the minimum output laser power, and whether a laser spot appears is observed through the theodolite 4. If the laser spot is not displayed in the theodolite 4, the output laser power of the adjustable fiber attenuator 8 is gradually increased until the laser spot can be clearly observed in the theodolite 4, and the knob of the adjustable fiber attenuator 8 is fixed at this time.

[0058] Next, the position and posture of the fiber optic collimator 24 are further fine-tuned using the robotic arm until the laser spot is completely aligned with the cross mark inside the theodolite 4 , which indicates that the preliminary adjustment of the fiber optic collimator 24 is completed.

[0059] S4, install the first mounting plate 22 on the motor translation stage 21, connect the fiber optic collimator 24 to the fiber optic attenuator 8 and the visible light laser 7 in sequence, adjust the first mounting plate 22 so that the light beam emitted by the visible light laser 7 passes through the fiber optic attenuator 8, a fiber optic collimator 24, a movable corner cube reflector 23, a fixed corner cube reflector 26, another movable corner cube reflector 23 and another fiber optic collimator 24 in sequence; fix the position of the first mounting plate 22 at this moment.

[0060] Specifically, Figure 6 As shown, the laser output by the visible light laser 7 is adjusted by the adjustable fiber attenuator 8 to attenuate its intensity. The adjusted laser is then introduced into the fiber collimator 24 through the optical fiber. Next, the power of the laser is gradually increased by the adjustable fiber attenuator 8 until the fiber collimator 24 can output a clearly visible, parallel thin beam. Next, the first mounting plate 22 is firmly mounted on the motor translation stage 21, and the position and posture of the first mounting plate 22 are carefully adjusted. The goal of this step is to ensure that the visible laser thin beam emitted by the fiber collimator 24 can accurately pass through the mobile corner reflector 23, the fixed corner reflector 26 and the mobile corner reflector 23 in sequence. In this process, each corner reflector will use the reflected beam of the previous corner reflector as its own incident beam to move and reflect laterally until the final beam is accurately incident on the end face center of another fiber collimator 24. When all the above adjustments have achieved the desired effect, the first mounting plate 22 is fixed at the current position. Finally, turn off the visible light laser 7.

[0061] S5, such as Figure 7 As shown, the visible light laser 7 is replaced by a test laser 5, the wavelength of the test laser 5 should be the same as the working wavelength of the optical fiber delay line; the optical fiber power meter 6 is connected to the optical fiber collimator 24 of the emitted light beam, and the first laser power value P of the input optical fiber collimator 24 is measured by adjusting the optical fiber attenuator 8. 0 and the second laser power value P output by the optical fiber collimator 24 1 , the coupling efficiency η of the optical fiber delay line is calculated according to the first laser power value and the second laser power value, and the calculation formula is as follows:

[0062]

[0063] Control the motor translation stage 21 to move from the initial zero position to the maximum stroke, and record the maximum coupling efficiency η of the optical fiber delay line during the movement of the motor translation stage 21 maxand the minimum coupling efficiency η min , based on the maximum coupling efficiency and the minimum coupling efficiency, calculate the fiber delay line coupling efficiency change rate α and the average value

[0064]

[0065] The positions and postures of the two optical fiber collimators 24 are adjusted respectively until the average value of the coupling efficiency of the optical fiber delay line is maximized and the change rate of the coupling efficiency of the optical fiber delay line is minimized.

[0066] After the adjustment is completed, the two fiber optic collimators 24 are fixed to the second mounting plate 25 by gluing. Before the glue solidifies, the fiber optic delay line coupling efficiency and the rate of change of the fiber optic delay line coupling efficiency are monitored every 4 hours. If any one of them changes, the corresponding fiber optic collimator 24 is adjusted until the average value of the fiber optic delay line coupling efficiency is maximized and the rate of change of the fiber optic delay line coupling efficiency is minimized.

[0067] Based on the same concept, Figure 8 As shown, the present invention provides a debugging platform 9, including: a connecting plate 91, a connecting rod 92, a universal joint 93, a first telescopic member 94, a second telescopic member 95, a first bolt 97 and a second bolt 96, the connecting plate 91 is connected to the base, the connecting plate 91 is connected to the universal joint 93 through the connecting rod 92, the universal joint 93 is arranged at the end of the first telescopic member 94, the first bolt 97 passes through the first telescopic member 94 and abuts against the universal joint 93, for constraining the rotation of the universal joint 93; the second telescopic member 95 is sleeved on the first telescopic member 94 and is slidably connected to the first telescopic member 94, the second bolt 96 passes through the second telescopic member 95 and abuts against the first telescopic member 94, for constraining the movement of the first telescopic member 94.

[0068] Specifically, the connecting plate 91 is used to connect the base, and is closely connected with the universal joint 93 through the connecting rod 92, so that the base can have flexible steering ability. The universal joint 93 is placed at the end of the first telescopic member 94, which not only inherits the force transmitted by the connecting plate 91 and the connecting rod 92, but also gives the debugging platform 9 the possibility of multi-directional adjustment. In order to effectively constrain the stability of the universal joint 93 when it does not need to rotate, the first bolt 97 penetrates the first telescopic member 94 and forms a close abutment relationship with the universal joint 93, ensuring that the universal joint 93 is fixed at the specified position. The second telescopic member 95 is sleeved on the first telescopic member 94 and cooperates with it by a sliding connection, which is convenient for adjusting the height of the debugging platform 9. In order to maintain the stability of the structure while achieving height changes, the second bolt 96 is designed to pass through the second telescopic member 95 and form an abutment with the first telescopic member 94, thereby limiting the free movement of the first telescopic member 94 in a non-adjusted state, ensuring the stability and accuracy of the entire debugging platform 9 during the adjustment process.

[0069] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0070] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A debugging method for a fast optical fiber delay line, characterized in that: The invention comprises a focusing autocollimator, a spherical reflector, a debugging platform, a base arranged on the debugging platform, a motor translation platform slidably connected to the base, a first mounting plate detachably connected to the motor translation platform, two movable corner cube reflectors connected to the first mounting plate, a second mounting plate detachably connected to the end of the base, and a fixed corner cube reflector connected to the second mounting plate; the movable corner cube reflector and the fixed corner cube reflector each comprise three reflecting surfaces, and the three reflecting surfaces are vertical and concave inwards; The method comprises: S1, arranging an inner focusing autocollimator and a spherical reflector according to a preset position, wherein the preset position satisfies that the spherical reflector is arranged on the motor translation stage, the reflective surface of the spherical reflector faces the inner focusing autocollimator, the center height of the spherical reflector is the same as the center height of the optical fiber delay line, and the central optical axis of the spherical reflector is collinear with the central optical axis of the inner focusing autocollimator; and the driving axis direction of the motor translation stage is taken as the direction of the main optical axis; Turning on the inner focusing autocollimator and the motor translation stage in sequence, controlling the motor translation stage to be in multiple positions, adjusting the focal length of the inner focusing autocollimator and the orientation and posture of the debugging stage at each position, so that the autocollimator cross image emitted by the inner focusing autocollimator and reflected back by the spherical reflector coincides with the standard cross image; removing the spherical reflector; S2, arrange the theodolite so that the center height of the theodolite is the same as the center height of the optical fiber delay line, and the theodolite faces the inner focusing autocollimator; install a second mounting plate and two optical fiber collimators symmetrical along the center line of the second mounting plate on the base; connect the optical fiber collimators to the optical fiber attenuator and the visible light laser in sequence, and adjust the position of the theodolite so that the parallel thin light beams emitted by the two optical fiber collimators can be received by the theodolite; then turn off the visible light laser, remove the second mounting plate and the optical fiber collimators, and make the parallel light beams emitted by the inner focusing autocollimator enter the theodolite; adjust the azimuth and posture of the theodolite so that the cross image of the inner focusing autocollimator and the cross image inside the theodolite overlap; S3, installing the second mounting plate on the base, and adjusting the two fiber optic collimators on the second mounting plate so that the optical axes of the two fiber optic collimators are parallel to the main optical axis respectively; S4, installing the first mounting plate on the motor translation stage, connecting the fiber collimator to the fiber attenuator and the visible light laser in sequence, adjusting the first mounting plate so that the light beam emitted by the visible light laser passes through the fiber attenuator, a fiber collimator, a movable corner reflector, a fixed corner reflector, another movable corner reflector and another fiber collimator in sequence; fixing the position of the first mounting plate at this moment; S5, replace the visible light laser with a test laser, the wavelength of the test laser should be the same as the working wavelength of the optical fiber delay line; connect the optical fiber power meter to the optical fiber collimator that emits the light beam, and measure the first laser power value of the input optical fiber collimator and the second laser power value of the output optical fiber collimator by adjusting the optical fiber attenuator, and calculate the coupling efficiency of the optical fiber delay line according to the first laser power value and the second laser power value; control the motor translation stage to move from an initial zero position to a maximum stroke, record the maximum coupling efficiency and the minimum coupling efficiency of the optical fiber delay line during the movement of the motor translation stage, and calculate the change rate and average value of the coupling efficiency of the optical fiber delay line based on the maximum coupling efficiency and the minimum coupling efficiency; adjust the orientation and posture of the two optical fiber collimators respectively until the average value of the coupling efficiency of the optical fiber delay line is maximized and the change rate of the coupling efficiency of the optical fiber delay line is minimized.

2. The method according to claim 1, characterized in that The step of arranging the inner focusing autocollimator and the spherical reflector according to the preset positions specifically includes: Measuring and recording the center height of the fixed corner reflector as the center height of the optical fiber delay line; Adjust the inner focusing autocollimator so that the center height of the inner focusing autocollimator is the same as the center height of the optical fiber delay line, and the inner focusing autocollimator faces the movable corner reflector; adjust the center optical axis of the inner focusing autocollimator to be parallel to the driving axis of the motor translation stage, and adjust the center optical axis of the inner focusing autocollimator to align with the center of the fixed corner reflector; Remove the second mounting plate and the first mounting plate; A spherical reflector is installed on the motor translation stage so that the reflective surface of the spherical reflector faces the inner focusing autocollimator, and the center height of the spherical reflector is the same as the center height of the optical fiber delay line, and the center optical axis of the spherical reflector is collinear with the center optical axis of the inner focusing autocollimator.

3. The method according to claim 1, characterized in that The step of adjusting the orientation and posture of the theodolite so that the cross image of the internal focusing autocollimator coincides with the cross image inside the theodolite specifically comprises: The focal length of the inner focusing autocollimator is adjusted so that the working distance of the inner focusing autocollimator is infinite, the parallel light beam emitted by the inner focusing autocollimator is incident on the theodolite, and the azimuth posture of the theodolite is adjusted so that the cross image of the inner focusing autocollimator and the cross image inside the theodolite overlap.

4. The method according to claim 1, characterized in that After the average value of the coupling efficiency of the optical fiber delay line is maximized and the rate of change of the coupling efficiency of the optical fiber delay line is minimized, the method further includes: Fix the two optical fiber collimators on the second mounting plate respectively by gluing; Before the glue solidifies, the optical fiber delay line coupling efficiency and the rate of change of the optical fiber delay line coupling efficiency are monitored at preset time intervals. If either one changes, the corresponding optical fiber collimator is adjusted until the average value of the optical fiber delay line coupling efficiency is maximized and the rate of change of the optical fiber delay line coupling efficiency is minimized.

5. A debugging platform, applied to the method according to any one of claims 1 to 4, characterized in that: The debugging platform includes: a connecting plate, a connecting rod, a universal joint, a first telescopic member, a second telescopic member, a first bolt and a second bolt, the connecting plate is connected to the base, the connecting plate is connected to the universal joint through the connecting rod, the universal joint is arranged at the end of the first telescopic member, the first bolt passes through the first telescopic member and abuts against the universal joint to constrain the rotation of the universal joint; the second telescopic member is sleeved on the first telescopic member and is slidably connected to the first telescopic member, the second bolt passes through the second telescopic member and abuts against the first telescopic member to constrain the movement of the first telescopic member.

Images