Polarization maintaining optical fiber countershaft welding device and welding method thereof

Abstract

The invention belongs to the technical field of optical fiber sensors, and particularly relates to a polarization-maintaining optical fiber countershaft welding device and a welding method thereof, which are characterized in that the welding device comprises a polarization light source system, a polarization beam splitter, a first photoelectric detector, a second photoelectric detector, a signal processor and an adjustable polarization-maintaining optical fiber welding machine, according to the welding method, when linearly polarized light generated by the polarized light source system passes through the operated polarization maintaining optical fiber, the linearly polarized light is decomposed into two beams of orthogonal linearly polarized light by the polarization beam splitter due to the existence of a countershaft angle, and the two beams of orthogonal linearly polarized light are subjected to photoelectric conversion by the photoelectric detector; and after being processed by the signal processor, the signals are sent to a control end of the adjustable polarization maintaining optical fiber fusion splicer as a pair of closed-loop control signals, so that a rotating end of the adjustable polarization maintaining optical fiber fusion splicer rotates to adjust the countershaft angle of the operated polarization maintaining optical fiber and realize countershaft fusion splicing at any angle. According to the invention, a closed loop can be formed to automatically adjust the countershaft angle, and welding of any countershaft angle of two sections of polarization maintaining fibers can be realized through one-time welding.

Description

Technical Field

[0001] The invention specifically relates to a polarization-maintaining optical fiber axial fusion splicing device and a fusion splicing method thereof, and belongs to the technical field of optical fiber sensors. Background Art

[0002] In recent years, polarization-maintaining optical fiber has been increasingly used as a transmission medium and sensing element for polarized light in optical fiber sensing. Different optical properties can be achieved by setting the splicing angle of polarization-maintaining optical fiber.

[0003] However, due to the inherent properties of polarization-maintaining optical fiber, the accuracy of its on-axis welding has a great influence on the performance of the optical sensing system. For example, when welding with a quarter-wave plate and a half-wave plate, the deviation of the welding angle will affect the deviation of the polarization state transition of the light, causing coupling interference of the optical system.

[0004] The existing polarization-maintaining fiber fusion splicing technology has always relied on monitoring the transmitted power to complete the axis alignment, which requires many additional equipment, such as light sources, polarizers, analyzers, power meters, and optical sensors. In addition, in order to inject polarized light at the light source end and detect polarized light at the detection end, the polarizer and analyzer must undergo a complex adjustment process.

[0005] There are several methods for polarization-maintaining fiber axial fusion splicing in the existing technology: First, the polarization-maintaining fiber axial adjustment method is to manually cut off the melting point according to the data analysis results of the data acquisition and processing display system after each fusion, manually adjust the five-dimensional fiber clamp to adjust the axial deviation for multiple fusions, and finally achieve the purpose of axial fusion of polarization-maintaining fibers at both ends; second, by setting a standard control group, if the test parameters of the fusion group and the control group are the same, then fusion is performed; if the test parameters are different from the control group, the rotating handle is manually adjusted to adjust until the parameters are the same as the control group to perform fusion splicing to achieve axial fusion; third, the relationship between the amplitude of the difference frequency and sum frequency signals in the detection signal and the fusion angle is used to calculate the relationship between the fusion angles of the two sections of optical fibers that need to be fusion-coordinated to deduce the current fusion angle. When the deduced fusion angle is different from the theoretical value, the axial module is manually adjusted to continuously reduce the difference between the current angle and the required fusion angle to achieve axial fusion. Regardless of the fusion method, manual adjustment is required repeatedly, and fusion of any axial angle cannot be achieved. Summary of the invention

[0006] The purpose of the present invention is to provide a polarization-maintaining optical fiber axial fusion splicing device which can form a closed loop and automatically adjust the axial angle, and can realize the axial fusion splicing of two sections of polarization-maintaining optical fibers at any axial angle in one fusion splicing.

[0007] In order to achieve the above-mentioned object, the first technical solution of the present invention is: a polarization-maintaining optical fiber axial fusion splicing device, the innovation of which is: comprising a polarization light source system, a polarization beam splitter, a first photodetector, a second photodetector, a signal processor and an adjustable polarization-maintaining optical fiber fusion splicing machine,

[0008] One end of the first polarization-maintaining optical fiber to be operated is connected to the output end of the polarization light source system, and the other end is connected to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer.

[0009] One end of the second polarization-maintaining optical fiber to be aligned in the polarization-maintaining optical fiber being operated is connected to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer, and the other end is connected to the access port of the polarization beam splitter.

[0010] The input end of the first photodetector and the input end of the second photodetector are respectively connected to the corresponding output ports of the polarization beam splitter, and the output end of the first photodetector and the output end of the second photodetector are respectively electrically connected to the input end of the signal processor, and the output end of the signal processor is electrically connected to the control end of the adjustable polarization-maintaining optical fiber fusion splicer.

[0011] When the linearly polarized light generated by the polarization light source system is transmitted to the second polarization-maintaining optical fiber to be aligned through the first polarization-maintaining optical fiber to be aligned, it is decomposed into two orthogonal beams of linear polarized light by the polarization beam splitter due to the existence of the alignment angle. The first photodetector and the second photodetector receive the two beams of linear polarized light output by the polarization beam splitter, and perform photoelectric conversion to generate voltage signals, which are processed by the signal processor as a pair of control signals for closed-loop control and sent to the control end of the adjustable polarization-maintaining optical fiber fusion splicer, so that its rotating end rotates to adjust the alignment angle of the second polarization-maintaining optical fiber to be aligned and realizes alignment fusion of any angle.

[0012] In the above-mentioned first technical solution, the polarized light source system includes a broadband light source, a single-mode optical fiber, a polarizer and a polarization-maintaining optical fiber. The broadband light source is arranged on one side of the single-mode optical fiber. The single-mode optical fiber is connected to one end of the polarization-maintaining optical fiber through the polarizer. The other end of the polarization-maintaining optical fiber is connected to one end of the first polarization-maintaining optical fiber to be aligned. The light emitted by the broadband light source generates linearly polarized light after passing through the polarizer, and is transmitted to the first polarization-maintaining optical fiber to be aligned through the polarization-maintaining optical fiber.

[0013] In the above first technical solution, the polarization light source system further comprises a polarization-maintaining fiber connector, and the other end of the polarization-maintaining fiber is connected to one end of the first polarization-maintaining fiber to be aligned via the polarization-maintaining fiber connector.

[0014] In the above-mentioned first technical solution, the polarization beam splitter has an access port and two output ports, wherein the two output ports are output port No. 1 and output port No. 2 respectively, and the access port of the polarization beam splitter is 0° fusion-connected to one end of the second polarization-maintaining optical fiber to be aligned, and the two beams of linear polarized light transmitted by the second polarization-maintaining optical fiber to be aligned are respectively transmitted through output port No. 1 and output port No. 2 to the corresponding first photodetector and second photodetector for photoelectric conversion, and at the same time, the first photodetector and the second photodetector are respectively fusion-connected to output port No. 1 and output port No. 2 of the polarization beam splitter at 0°.

[0015] In the above-mentioned first technical solution, the signal processor includes a signal amplifying circuit, which is used to amplify the voltage signals output by the first photodetector and the second photodetector. The signal amplifying circuit adopts a triode circuit structure or is an integrated circuit composed of a signal amplifying chip.

[0016] In the first technical solution, the adjustable polarization-maintaining optical fiber fusion splicer includes a first optical fiber clamp, a second optical fiber clamp, a stepper motor, a stepper motor driver, a first optical fiber clamp operating table, and a second optical fiber clamp operating table.

[0017] The first optical fiber clamp is arranged on the first optical fiber clamp operating table and is used as a fixed end to clamp the other end of the first polarization-maintaining optical fiber to be aligned.

[0018] The second optical fiber clamp is arranged on the second optical fiber clamp operating table, and the driving shaft of the stepping motor is in transmission connection with the second optical fiber clamp to drive the second optical fiber clamp to rotate, so that the second optical fiber clamp serves as a rotating end and is used to clamp one end of the second optical fiber to be aligned.

[0019] The stepper motor driver access end is used as a control end and is electrically connected to the output end of the signal processor. The stepper motor is electrically connected to the output end of the stepper motor driver. The rotation start and stop of the stepper motor is controlled by the voltage input by the stepper motor driver as a driving signal. The positive and negative voltage determines the rotation direction of the stepper motor.

[0020] The input voltage of the stepper motor driver is equal to the difference between the two voltage signals output by the signal processor, and the stepper motor driver can set the stepper motor rotation termination voltage.

[0021] In order to achieve the above object, the second technical solution of the present invention is: a method for axially fusion splicing polarization-maintaining optical fibers according to the above device, the innovation of which lies in: the specific steps are:

[0022] Step a, connecting one end of the first polarization-maintaining optical fiber to be operated to the output end of the polarization light source system, and the other end to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer, and then connecting one end of the second polarization-maintaining optical fiber to be operated to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer, and the other end to the access port of the polarization beam splitter,

[0023] Step b, when the linear polarized light generated by the polarization light source system is transmitted to the second polarization maintaining optical fiber to be aligned through the first axis-aligned polarization maintaining optical fiber, the linear polarized light is divided into two orthogonal beams of linear polarized light due to the existence of the axis-aligned angle, and is transmitted in the second axis-aligned polarization maintaining optical fiber, and then transmitted to the access port of the polarization beam splitter, and the polarization beam splitter separates the two orthogonal beams of linear polarized light, and the separated linear polarized light is respectively transmitted to the first photodetector and the second photodetector from the corresponding access ports, and the light intensity of the two beams of linear polarized light is converted into two voltage signals through photoelectric conversion.

[0024] In step c, the two voltage signals in step b are processed by a signal processor as control signals to form a closed-loop control of the welding angle, and the control signal is transmitted to the control end of the adjustable polarization-maintaining fiber fusion splicer to drive the rotating end of the adjustable polarization-maintaining fiber fusion splicer to rotate, thereby driving the second polarization-maintaining fiber to be aligned to rotate, and setting the rotation end termination condition in combination with the relationship between the rotation angle and the rotation termination voltage to achieve accurate alignment welding of the first polarization-maintaining fiber to be aligned and the second polarization-maintaining fiber to be aligned at any angle.

[0025] In the second technical solution, the vibration amplitudes A1 and A2 of the two orthogonal linear polarized lights in the second polarization-maintaining optical fiber to be aligned are:

[0026] A1=A0sin(θ)

[0027] A2=A0cos(θ)

[0028] Where θ is the alignment angle between the first polarization-maintaining fiber to be aligned and the second polarization-maintaining fiber to be aligned, A0 is the vibration amplitude of the linear polarization light in the first polarization-maintaining fiber to be aligned,

[0029] The optical signal power amplitude P1 sensed by the first photodetector is:

[0030]

[0031] The optical signal power amplitude P2 sensed by the second photodetector is:

[0032]

[0033] Where k1 is the photoelectric conversion coefficient of the photodetector,

[0034] Then the power ratio of the two polarized lights passing through the second polarization-maintaining optical fiber is:

[0035] ε=10lg(tan 2 (θ))=20lg(tan(θ))

[0036] The rotating end of the adjustable polarization-maintaining optical fiber fusion splicer is driven to rotate by a stepper motor, and the stepper motor adopts a voltage signal difference U c As a control signal to control the rotor rotation, the rotation termination condition is determined by the set rotation termination voltage U s Decide,

[0037] The control signal U is generated by the signal processor after the electrical signal converted by the first photodetector and the second photodetector is processed. c :

[0038]

[0039] Where k2 is the proportional coefficient of the signal processor,

[0040] The stepper motor is driven and controlled by a stepper motor driver, and the stepper motor driver sets a rotation termination voltage signal U s Control termination, rotation termination voltage signal U s The value is determined by the required axis angle of the polarization-maintaining fiber being operated, and the rotation termination voltage signal U s Proportional to the ratio of the powers presented to the pair of axis angles:

[0041] U s =k3ε

[0042] Where k3 is the rotation termination voltage U s The proportionality factor of the ratio to power,

[0043] When the control voltage signal U c >U s , the stepping motor rotates counterclockwise;

[0044] When the control voltage signal U c s , the stepping motor rotates clockwise;

[0045] When the control voltage signal U c =U s , the stepper motor stops rotating.

[0046] The positive effect of the present invention is that after adopting the polarization-maintaining optical fiber axial fusion splicing device and the fusion splicing method of the present invention, wherein the fusion splicing device includes a polarization light source system, a polarization beam splitter, a first photodetector, a second photodetector, a signal processor and an adjustable polarization-maintaining optical fiber fusion splicing machine,​

[0047] One end of the first polarization-maintaining optical fiber to be operated is connected to the output end of the polarization light source system, and the other end is connected to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer.

[0048] One end of the second polarization-maintaining optical fiber to be aligned in the polarization-maintaining optical fiber being operated is connected to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer, and the other end is connected to the access port of the polarization beam splitter.

[0049] The input end of the first photodetector and the input end of the second photodetector are respectively connected to the corresponding output ports of the polarization beam splitter, and the output end of the first photodetector and the output end of the second photodetector are respectively electrically connected to the input end of the signal processor, and the output end of the signal processor is electrically connected to the control end of the adjustable polarization-maintaining optical fiber fusion splicer.

[0050] The fusion splicing method is that when the linear polarized light generated by the polarization light source system is transmitted to the second polarization-maintaining optical fiber to be aligned through the first polarization-maintaining optical fiber to be aligned, the linear polarized light is decomposed into two orthogonal beams of linear polarized light due to the existence of the axial angle and enters the polarization beam splitter for separation, the first photodetector and the second photodetector receive the two beams of polarized light output by the polarization beam splitter, and the light intensity of the two beams of linear polarized light is converted into two voltage signals through photoelectric conversion, the two voltage signals are processed by the signal processor and used as control signals to form a closed-loop control of the fusion splicing angle, and the control signal is transmitted to the control end of the adjustable polarization-maintaining optical fiber fusion splicer to drive the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer to rotate, thereby driving the second polarization-maintaining optical fiber to be aligned to rotate, so as to realize the precise axial fusion splicing of the first polarization-maintaining optical fiber to be aligned and the second polarization-maintaining optical fiber to be aligned at any angle,

[0051] Specifically, based on the relationship between the power ratio and the axis alignment angle, the present invention uses a polarization beam splitter to separate the two orthogonal polarized lights generated when the polarization-maintaining optical fiber is aligned, and generates two electrical signals as control signals through a first photodetector and a second photodetector, respectively, to construct a closed-loop control system for a closed welding angle, drives the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer to rotate, and sets the rotation termination condition of the optical fiber clamp in combination with the relationship between the rotation angle and the rotation termination voltage to achieve precise axis alignment welding of the polarization-maintaining optical fiber at any angle.

[0052] Therefore, the entire process of the present invention can form a closed loop to automatically adjust the axis angle, without the need for manual adjustment or setting up a control group, and the light intensity difference (converted into a voltage signal by a photoelectric detector) is used to adjust the axis angle in real time, so that two sections of polarization-maintaining optical fibers can be welded at any axis angle in one welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a structural schematic diagram of the polarization-maintaining optical fiber axial fusion splicing device of the present invention;

[0054] Figure 2 It is a simplified view of the adjustable polarization-maintaining optical fiber fusion splicer of the present invention;

[0055] Figure 3 It is a schematic diagram of the arbitrary angle welding of polarization-maintaining optical fibers according to the present invention;

[0056] Figure 4 It is a schematic diagram of the structure of the adjustable optical fiber fusion splicer of the present invention;

[0057] In the figure: polarized light source system 1, broadband light source 101, single-mode optical fiber 102, polarizer 103, polarization-maintaining optical fiber 104, polarization-maintaining optical fiber connector 105, polarization beam splitter 2, first photodetector 3, second photodetector 4, signal processor 5, adjustable polarization-maintaining optical fiber fusion splicer 6, first optical fiber clamp 601, second optical fiber clamp 602, stepper motor 603, stepper motor driver 604, first optical fiber clamp operating table 605, second optical fiber clamp operating table 606, operated polarization-maintaining optical fiber 7, first polarization-maintaining optical fiber 701, second polarization-maintaining optical fiber 702. DETAILED DESCRIPTION

[0058] The present invention is further described below with reference to the accompanying drawings and given embodiments, but is not limited thereto.

[0059] Example 1

[0060] like Figure 1 , 2 , 3, and 4, a polarization-maintaining optical fiber fusion splicing device comprises a polarization light source system 1, a polarization beam splitter 2, a first photodetector 3, a second photodetector 4, a signal processor 5, and an adjustable polarization-maintaining optical fiber fusion splicer 6.

[0061] One end of the first polarization-maintaining optical fiber 701 to be aligned in the polarization-maintaining optical fiber 7 is connected to the output end of the polarization light source system 1, and the other end is connected to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer 6.

[0062] One end of the second polarization-maintaining optical fiber 702 to be aligned in the polarization-maintaining optical fiber 7 is connected to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer 6, and the other end is connected to the access port of the polarization beam splitter 2.

[0063] The input end of the first photodetector 3 and the input end of the second photodetector 4 are respectively connected to the corresponding output ports of the polarization beam splitter 2, and the output end of the first photodetector 3 and the output end of the second photodetector 4 are respectively electrically connected to the input end of the signal processor 5, and the output end of the signal processor 5 is electrically connected to the control end of the adjustable polarization-maintaining optical fiber fusion splicer 6.

[0064] When the linearly polarized light generated by the polarization light source system 1 is transmitted to the second polarization-maintaining optical fiber 702 to be aligned through the first polarization-maintaining optical fiber 701 to be aligned, it is decomposed into two orthogonal beams of linear polarized light by the polarization beam splitter 2 due to the existence of the alignment angle. The first photodetector 3 and the second photodetector 4 receive the two beams of linear polarized light output by the polarization beam splitter 2, and perform photoelectric conversion to generate voltage signals, which are processed by the signal processor 5 and sent to the control end of the adjustable polarization-maintaining optical fiber fusion splicer 6 as a control signal to form a pair of closed-loop control, so that its rotating end rotates to adjust the alignment angle of the second polarization-maintaining optical fiber 702 to be aligned and realize alignment fusion of any angle.

[0065] like Figure 1 As shown, the polarized light source system 1 includes a broadband light source 101, a single-mode optical fiber 102, a polarizer 103 and a polarization-maintaining optical fiber 104. The broadband light source 101 is arranged on one side of the single-mode optical fiber 102. The single-mode optical fiber 102 is connected to one end of the polarization-maintaining optical fiber 104 through the polarizer 103. The other end of the polarization-maintaining optical fiber 104 is connected to one end of the first polarization-maintaining optical fiber 701 to be aligned. The light emitted by the broadband light source 101 generates linearly polarized light after passing through the polarizer 103, and is transmitted to the first polarization-maintaining optical fiber 701 to be aligned with the polarization maintaining optical fiber 104 as a medium.

[0066] like Figure 1 As shown, in order to facilitate the rapid and effective connection between the polarization light source system and the first polarization-maintaining optical fiber to be aligned, the polarization light source system 1 also includes a polarization-maintaining optical fiber connector 105, and the other end of the polarization-maintaining optical fiber 104 is connected to one end of the first polarization-maintaining optical fiber 701 to be aligned through the polarization-maintaining optical fiber connector 105.

[0067] Furthermore, the polarization beam splitter 2 has an access port and two output ports, wherein the two output ports are output port No. 1 and output port No. 2 respectively. The access port of the polarization beam splitter 2 is fused-connected with one end of the second polarization-maintaining optical fiber 702 to be aligned at 0°. The two beams of linearly polarized light transmitted by the second polarization-maintaining optical fiber 702 to be aligned are transmitted through output port No. 1 and output port No. 2 respectively to the corresponding first photodetector 3 and second photodetector 4 for photoelectric conversion. At the same time, the first photodetector 3 and the second photodetector 4 are fused-connected with output port No. 1 and output port No. 2 of the polarization beam splitter 2 respectively at 0°.

[0068] Furthermore, in order to process and amplify the received voltage signal, the signal processor 5 includes a signal amplification circuit, which is used to amplify the voltage signal output by the first photodetector 3 and the second photodetector 4. The signal amplification circuit adopts a circuit structure with a transistor as the core or an integrated circuit composed of a signal amplification chip. Specifically, the signal amplification chip is used as the core of the integrated circuit, and resistors and capacitors constitute the peripheral circuit.

[0069] like Figure 2 , 4 As shown, in order to make the structure more reasonable and controllable, the adjustable polarization-maintaining optical fiber fusion splicer 6 includes a first optical fiber clamp 601, a second optical fiber clamp 602, a stepper motor 603, a stepper motor driver 604, a first optical fiber clamp operating table 605 and a second optical fiber clamp operating table 606.

[0070] The first optical fiber clamp 601 is disposed on the first optical fiber clamp operating table 605 and is used as a fixed end to clamp the other end of the first polarization-maintaining optical fiber 701 to be aligned.

[0071] The second optical fiber clamp 602 is disposed on a second optical fiber clamp operating table 606, and the driving shaft of the stepping motor 603 is in transmission connection with the second optical fiber clamp 602, so as to drive the second optical fiber clamp 602 to rotate, so that the second optical fiber clamp 602 serves as a rotating end and is used to clamp one end of the second polarization-maintaining optical fiber 702 to be aligned.

[0072] The access end of the stepper motor driver 604 is used as a control end and is electrically connected to the output end of the signal processor 5. The stepper motor 603 is electrically connected to the output end of the stepper motor driver 604. The rotation start and stop of the stepper motor 603 is controlled by the voltage input by the stepper motor driver 604 as a driving signal. The positive or negative voltage determines the rotation direction of the stepper motor 603.

[0073] The input voltage of the stepper motor driver 604 is equal to the difference between the two voltage signals output by the signal processor 5 , and the stepper motor driver 604 can set the rotation termination voltage of the stepper motor 603 .

[0074] Example 2

[0075] like Figure 1 , 3 As shown in 4, a method for axially fusing polarization-maintaining optical fibers of the above device, the specific steps are:

[0076] Step a, one end of the first polarization-maintaining optical fiber 701 to be aligned in the polarization-maintaining optical fiber 7 to be operated is connected to the output end of the polarization light source system 1, and the other end is connected to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer 6, and then one end of the second polarization-maintaining optical fiber 702 to be aligned in the polarization-maintaining optical fiber 7 to be operated is connected to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer 6, and the other end is connected to the access port of the polarization beam splitter 2,

[0077] Step b, when the linearly polarized light generated by the polarization light source system 1 is transmitted to the second polarization-maintaining optical fiber 702 through the first polarization-maintaining optical fiber 701 to be aligned, the linearly polarized light is divided into two orthogonal beams of linearly polarized light due to the existence of the axis angle, and is transmitted in the second polarization-maintaining optical fiber 702 to be aligned, and then transmitted to the access port of the polarization beam splitter 2, and the polarization beam splitter 2 separates the two orthogonal beams of linearly polarized light, and the separated linearly polarized light is respectively transmitted to the first photodetector 3 and the second photodetector 4 from the corresponding access ports, and the light intensity of the two beams of linearly polarized light is converted into two voltage signals through photoelectric conversion.

[0078] In step c, the two voltage signals in step b are processed by the signal processor 5 and used as control signals to construct a closed-loop control of the welding angle. At the same time, the control signal is transmitted to the control end of the adjustable polarization-maintaining fiber fusion splicer 6 to drive the rotating end of the adjustable polarization-maintaining fiber fusion splicer 6 to rotate, thereby driving the second polarization-maintaining optical fiber 702 to be aligned to rotate, and setting the rotation end termination condition based on the relationship between the rotation angle and the rotation termination voltage to achieve precise alignment welding of the first polarization-maintaining optical fiber 701 to be aligned and the second polarization-maintaining optical fiber 702 to be aligned at any angle.

[0079] Furthermore, the magnitudes of the electrical signals generated by the first photodetector 3 and the second photodetector 4 are proportional to the amplitudes of the two polarized light beams.

[0080] The vibration amplitudes A1 and A2 of the two orthogonal linear polarized lights in the second polarization-maintaining optical fiber 702 are:

[0081] A1=A0sin(θ)

[0082] A2=A0cos(θ)

[0083] Wherein θ is the axial angle between the first polarization-maintaining optical fiber 701 to be aligned and the second polarization-maintaining optical fiber 702 to be aligned, A0 is the vibration amplitude of the linear polarization light in the first polarization-maintaining optical fiber 701 to be aligned,

[0084] The optical signal power amplitude P1 sensed by the first photodetector 3 is:

[0085]

[0086] The optical signal power amplitude P2 sensed by the second photodetector 4 is:

[0087]

[0088] Where k1 is the photoelectric conversion coefficient of the photodetector,

[0089] Then the power ratio of the two polarized lights passing through the second aligned-axis polarization-maintaining optical fiber 702 is:

[0090] ε=10lg(tan 2 (θ))=20lg(tan(θ))

[0091] The rotating end of the adjustable polarization-maintaining optical fiber fusion splicer 6 is driven to rotate by a stepper motor 603. The stepper motor 603 uses a voltage signal difference U c As a control signal to control the rotor rotation, the rotation termination condition is determined by the set rotation termination voltage U s Decide,

[0092] The voltage signals converted by the first photodetector 3 and the second photodetector 4 are processed by the signal processor 5 to generate a control signal U c :

[0093]

[0094] Where k2 is the proportional coefficient of the signal processor,

[0095] Furthermore, the stepper motor driver 604 of the adjustable polarization-maintaining optical fiber fusion splicer 6 can be used to set a rotation termination voltage, and the rotation termination voltage is determined by the ratio of the power corresponding to the required fusion angle.

[0096] The stepper motor 603 is driven and controlled by a stepper motor driver 604, and the stepper motor driver 604 sets a rotation termination voltage signal U s , whose value is determined by the required axial angle of the polarization-maintaining optical fiber 7 to be operated, and the rotation termination voltage signal U s Proportional to the ratio of the powers presented to the pair of axis angles:

[0097] U s =k3ε

[0098] Where k3 is the rotation termination voltage U s The proportionality factor to the power ratio,

[0099] When the control voltage signal U c >U s , the stepping motor 603 rotates counterclockwise;

[0100] When the control voltage signal U c s , the stepping motor 603 rotates clockwise;

[0101] When the control voltage signal U c =U s , the stepping motor 603 stops rotating.

[0102] When setting the termination voltage U s When U is 0, c =U s ​=0, the stepping motor stops rotating. At this time, the axis-aligning angle θ of the first polarization-maintaining optical fiber 701 to be aligned and the second polarization-maintaining optical fiber 702 to be aligned is 45°.

[0103] In more common applications, the rotation termination voltage U is set according to the relationship between the power ratio and the shaft welding angle. s , it can realize the fusion of polarization-maintaining optical fiber at any angle.

[0104] The precise axial fusion splicing device for polarization-maintaining optical fibers of the present invention separates two orthogonal polarized lights through a polarization beam splitter 2 based on the relationship between the power ratio and the axial angle, and performs photoelectric conversion through a first photodetector 3 and a second photodetector 4, respectively, converting the optical signal into a voltage signal to drive a stepper motor 603 to rotate to control the fusion angle, and controls the fusion angle by comparing the fusion angle with the rotation termination voltage U s The relationship between the rotation end voltage U s The rotation stop is controlled to achieve precise splicing of polarization-maintaining optical fibers at specific angles.

[0105] Therefore, the entire process of the present invention can form a closed loop to automatically adjust the axis angle, without the need for manual adjustment or setting up a control group, and the light intensity difference (converted into a voltage signal by a photoelectric detector) is used to adjust the axis angle in real time, so that two sections of polarization-maintaining optical fibers can be welded at any axis angle in one welding.

[0106] It should be noted that the quarter wave plate is an important optical device for converting linear polarized light into circular polarized light. The quarter wave plate is a polarization-maintaining fiber with a length of 1 / 4 beat length. When used, the incident linear polarized light and the quarter beat length polarization-maintaining fiber are incident at 45 degrees. If the deviation is large, the linear polarized light will be converted into non-standard elliptically polarized light. A special application of the present invention is to precisely 45 degrees weld the polarization-maintaining fiber that transmits linear polarized light with the quarter wave plate, thereby realizing the conversion of linear polarized light into circular polarized light.

[0107] A common application of the present invention is 0° welding, which is mostly used for maintaining the polarization state of polarized light to ensure that the polarization state of light is not affected during transmission.

[0108] The 90° welding of the present invention is used for exchanging the polarization states of light, and welding at other angles is mostly used for building specific optical systems and testing system characteristics.

[0109] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A polarization-maintaining optical fiber axial fusion splicing device, characterized in that: It comprises a polarization light source system (1), a polarization beam splitter (2), a first photodetector (3), a second photodetector (4), a signal processor (5) and an adjustable polarization-maintaining optical fiber fusion splicer (6). One end of the first polarization-maintaining optical fiber (701) to be aligned in the polarization-maintaining optical fiber (7) to be operated is connected to the output end of the polarization light source system (1), and the other end is connected to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer (6). One end of the second polarization-maintaining optical fiber (702) to be aligned in the polarization-maintaining optical fiber (7) to be operated is connected to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer (6), and the other end is connected to the access port of the polarization beam splitter (2). The input end of the first photodetector (3) and the input end of the second photodetector (4) are respectively connected to the corresponding output ports of the polarization beam splitter (2), and the output end of the first photodetector (3) and the output end of the second photodetector (4) are respectively electrically connected to the input end of the signal processor (5), and the output end of the signal processor (5) is electrically connected to the control end of the adjustable polarization-maintaining optical fiber fusion splicer (6). When the linearly polarized light generated by the polarization light source system (1) is transmitted to the second polarization-maintaining optical fiber (702) to be aligned through the first polarization-maintaining optical fiber (701), it is decomposed into two orthogonal beams of linearly polarized light by the polarization beam splitter (2) due to the existence of the alignment angle. The first photodetector (3) and the second photodetector (4) receive the two beams of linearly polarized light output by the polarization beam splitter (2), and perform photoelectric conversion to generate voltage signals. After being processed by the signal processor (5), the signals are sent to the control end of the adjustable polarization-maintaining optical fiber fusion splicer (6) as a pair of control signals for forming a closed-loop control, so that the rotating end thereof rotates to adjust the alignment angle of the second polarization-maintaining optical fiber (702) to be aligned and to achieve alignment fusion splicing at any angle.

2. The polarization-maintaining optical fiber axial fusion splicing device according to claim 1, characterized in that: The polarized light source system (1) comprises a broadband light source (101), a single-mode optical fiber (102), a polarizer (103) and a polarization-maintaining optical fiber (104); the broadband light source (101) is arranged on one side of the single-mode optical fiber (102); the single-mode optical fiber (102) is connected to one end of the polarization-maintaining optical fiber (104) via the polarizer (103); the other end of the polarization-maintaining optical fiber (104) is connected to one end of a first polarization-maintaining optical fiber (701) to be aligned; light emitted by the broadband light source (101) generates linearly polarized light after passing through the polarizer (103), and is transmitted to the first polarization-maintaining optical fiber (701) to be aligned via the polarization-maintaining optical fiber (104).

3. The polarization-maintaining optical fiber axial fusion splicing device according to claim 2, characterized in that: The polarized light source system (1) further comprises a polarization-maintaining optical fiber connector (105), and the other end of the polarization-maintaining optical fiber (104) is connected to one end of a first polarization-maintaining optical fiber (701) to be aligned via the polarization-maintaining optical fiber connector (105).

4. The polarization-maintaining optical fiber axial fusion splicing device according to claim 1, characterized in that: The polarization beam splitter (2) has an access port and two output ports, wherein the two output ports are output port No. 1 and output port No. 2, respectively. The access port of the polarization beam splitter (2) is fused-connected at 0° to one end of a second polarization-maintaining optical fiber (702) to be aligned, and two beams of linearly polarized light transmitted by the second polarization-maintaining optical fiber (702) to be aligned are transmitted to the corresponding first photodetector (3) and second photodetector (4) through output port No. 1 and output port No. 2, respectively, for photoelectric conversion. At the same time, the first photodetector (3) and the second photodetector (4) are fused-connected at 0° to output port No. 1 and output port No. 2 of the polarization beam splitter (2), respectively.

5. The polarization-maintaining optical fiber axial fusion splicing device according to claim 1, characterized in that: The signal processor (5) comprises a signal amplifying circuit, which is used to amplify the voltage signals output by the first photodetector (3) and the second photodetector (4). The signal amplifying circuit adopts a triode circuit structure or is an integrated circuit composed of a signal amplifying chip.

6. The polarization-maintaining optical fiber axial fusion splicing device according to claim 1, characterized in that: The adjustable polarization-maintaining optical fiber fusion splicer (6) comprises a first optical fiber clamp (601), a second optical fiber clamp (602), a stepper motor (603), a stepper motor driver (604), a first optical fiber clamp operating table (605) and a second optical fiber clamp operating table (606). The first optical fiber clamp (601) is arranged on a first optical fiber clamp operating table (605) and is used as a fixed end to clamp the other end of the first polarization-maintaining optical fiber (701) to be aligned. The second optical fiber clamp (602) is arranged on a second optical fiber clamp operating table (606), and the driving shaft of the stepping motor (603) is in transmission connection with the second optical fiber clamp (602) for driving the second optical fiber clamp (602) to rotate, so that the second optical fiber clamp (602) serves as a rotating end and is used to clamp one end of the second polarization-maintaining optical fiber (702) to be aligned. The access end of the stepper motor driver (604) serves as a control end and is electrically connected to the output end of the signal processor (5). The stepper motor (603) is electrically connected to the output end of the stepper motor driver (604). The rotation start and stop of the stepper motor (603) is controlled by the voltage input by the stepper motor driver (604) as a driving signal. The positive or negative voltage determines the rotation direction of the stepper motor (603). The input voltage of the stepper motor driver (604) is equal to the difference between the two voltage signals output by the signal processor (5), and the stepper motor driver (604) can set the rotation termination voltage of the stepper motor (603).

7. A method for axially splicing polarization-maintaining optical fibers according to any one of claims 1 to 6, characterized in that: The specific steps are: Step a, connecting one end of the first polarization-maintaining optical fiber (701) to be aligned in the polarization-maintaining optical fiber (7) to the output end of the polarization light source system (1), and connecting the other end to the fixed end of the adjustable polarization-maintaining optical fiber fusion splicer (6), and then connecting one end of the second polarization-maintaining optical fiber (702) to be aligned in the polarization-maintaining optical fiber (7) to the rotating end of the adjustable polarization-maintaining optical fiber fusion splicer (6), and connecting the other end to the access port of the polarization beam splitter (2), Step b, when the linearly polarized light generated by the polarization light source system (1) is transmitted to the second polarization-maintaining optical fiber (702) to be aligned through the first polarization-maintaining optical fiber (701), the linearly polarized light is divided into two orthogonal beams of linearly polarized light due to the existence of the alignment angle, and is transmitted in the second polarization-maintaining optical fiber (702) to be aligned, and then transmitted to the access port of the polarization beam splitter (2), and the polarization beam splitter (2) separates the two orthogonal beams of linearly polarized light, and the separated linearly polarized light is respectively transmitted to the first photodetector (3) and the second photodetector (4) from the corresponding access ports, and the light intensity of the two beams of linearly polarized light is converted into two voltage signals through photoelectric conversion. In step c, the two voltage signals in step b are processed by the signal processor (5) and used as control signals to construct a closed-loop control of the welding angle. At the same time, the control signal is transmitted to the control end of the adjustable polarization-maintaining optical fiber welding machine (6), driving the rotating end of the adjustable polarization-maintaining optical fiber welding machine (6) to rotate, thereby driving the second polarization-maintaining optical fiber (702) to be aligned to rotate, and setting the rotation end termination condition based on the relationship between the rotation angle and the rotation termination voltage, so as to realize the precise alignment welding of the first polarization-maintaining optical fiber (701) to be aligned and the second polarization-maintaining optical fiber (702) to be aligned at any angle.

8. The method for axially fusion splicing polarization-maintaining optical fibers according to claim 7, characterized in that: The vibration amplitudes A1 and A2 of the two orthogonal linear polarized lights in the second polarization-maintaining optical fiber (702) are: A1=A0sin(θ) A2=A0cos(θ) Wherein θ is the axis-aligning angle between the first polarization-maintaining optical fiber (701) to be aligned and the second polarization-maintaining optical fiber (702) to be aligned, A0 is the vibration amplitude of the linear polarization light in the first polarization-maintaining optical fiber (701) to be aligned, The optical signal power amplitude P1 sensed by the first photodetector (3) is: The optical signal power amplitude P2 sensed by the second photodetector (4) is: Where k1 is the photoelectric conversion coefficient of the photodetector, Then the power ratio of the two polarized lights passing through the second polarization-maintaining optical fiber (702) is: ε=10lg(tan 2 (θ))=20lg(tan(θ)) The rotating end of the adjustable polarization-maintaining optical fiber fusion splicer (6) is driven to rotate by a stepper motor (603), and the stepper motor (603) uses a voltage signal difference U c As a control signal to control the rotor rotation, the rotation termination condition is determined by the set rotation termination voltage U s Decide, The voltage signals converted by the first photodetector (3) and the second photodetector (4) are processed by the signal processor (5) to generate a control signal U c : Where k2 is the proportional coefficient of the signal processor, The stepper motor (603) is driven and controlled by a stepper motor driver (604), and a rotation termination voltage signal U is set by the stepper motor driver (604). s Control termination, rotation termination voltage signal U s The value is determined by the required axial angle of the polarization-maintaining optical fiber (7) being operated, and the rotation termination voltage signal U s Proportional to the ratio of the powers presented to the pair of axis angles: And s =k3ε Where k3 is the rotation termination voltage U s The proportionality factor to the power ratio, When the control voltage signal U c >U s , the stepping motor (603) rotates counterclockwise; When the control voltage signal U c s , the stepping motor (603) rotates clockwise;​ When the control voltage signal U c =U s , the stepper motor (603) stops rotating.

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