Optical fiber nutation coupling system and method based on double-optical-wedge scanning

Abstract

The invention provides an optical fiber nutation coupling system and method based on double-optical-wedge scanning, and relates to the technical field of free space optical communication, and the system comprises a double-optical-wedge scanning system, a nutation coupling mirror and an optical fiber which are sequentially arranged along an optical path. The double-optical-wedge scanning system is provided with two optical wedges, the vertical faces are parallel and opposite, the wedge faces are opposite, and nutation scanning is carried out through reverse and / or same-direction rotation of the two optical wedges. The nutation coupling mirror is used for focusing the target light beam into a light spot to be emitted to the optical fiber; the optical power meter, the nutation controller, the double-optical-wedge scanning system driver and the double-optical-wedge scanning system are electrically connected in sequence; the optical power meter is connected with the optical fiber transmitting end and used for measuring the optical power of the target beam coupled into the optical fiber; and the nutation controller is used for resolving the rotation angles of the two optical wedges, controlling the driver of the double-optical-wedge scanning system to apply voltage, and performing linkage control on the two optical wedges. According to the invention, the rotation of the two optical wedges is dynamically optimized, so that high and stable light output coupling efficiency is ensured, and power consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of free space optical communication, and in particular to a fiber optic nutation coupling system and method based on double optical wedge scanning. Background Art

[0002] In recent years, with the increasing maturity of spaceborne laser communication terminal technology and the success of in-orbit link establishment between satellites and between satellite and ground, a wave of enthusiasm for inter-satellite laser communication has been set off in the field of free space optical communication technology, and the commercialization of laser communication terminals has become increasingly urgent. Due to optical machining, alignment deviation, micro-deformation of the mechanical structure caused by on-orbit temperature and stress changes of the satellite platform, platform vibration, and the influence of system transceiver non-coaxiality, it is extremely difficult to couple the weak signal light entering the optical system into a 9-μm single-mode optical fiber. Therefore, an efficient and stable coupling technology for free space optical coupling into a single-mode optical fiber is the prerequisite and guarantee for the realization of high-speed long-distance laser communication technology, and it is also a key technology in space laser communication, which urgently needs to be solved to ensure a rapid and stable improvement of the coupling efficiency, and further guarantee the quality of free space laser communication.

[0003] Existing fiber optic nutation coupling devices usually use a fast steering mirror as the nutation mirror, and adjust the incident light angle by adjusting the fast steering mirror to achieve nutation coupling. However, in addition to problems such as the large weight and volume of the fast steering mirror, its large power consumption cannot be ignored. Therefore, it is of great significance to adopt a new method to perform adaptive free space optical-single mode fiber coupling with a structure that does not increase the fast steering mirror and has a relatively simple structure, high system integration, and strong space utilization. Summary of the Invention

[0004] The purpose of the present invention is to provide a fiber optic nutation coupling system and method based on double optical wedge scanning to solve at least one of the above technical problems existing in the prior art.

[0005] In a first aspect, to solve the above technical problems, a fiber optic nutation coupling system based on double optical wedge scanning provided by the present invention includes: a double optical wedge scanning system, a nutation coupling mirror, an optical fiber, an optical power meter, a nutation controller, and a double optical wedge scanning system driver; The double optical wedge scanning system, the nutation coupling mirror, and the optical fiber are arranged in sequence along the optical path. During use, the target beam is incident parallelly, passes through the double optical wedge scanning system and the nutation coupling mirror in sequence, and is directed to the optical fiber; The double optical wedge scanning system is provided with two optical wedges. The vertical planes (i.e., the mirror surfaces perpendicular to the optical axis) of the two optical wedges are parallel and arranged facing each other, and the wedge surfaces of the two optical wedges are arranged back to back. During use, the target beam passes through the two optical wedges in sequence, exits from the wedge surface of the optical wedge closer to the nutation coupling mirror, and irradiates on the nutation coupling mirror to form a light spot. By rotating the two optical wedges in the reverse and / or same direction, a deflected free-space optical axis angle is formed, thereby controlling the nutation scanning of the light spot on the nutation coupling mirror; The nutation coupling mirror is used for focusing the target beam. The target beam converges into a light point through the nutation coupling mirror and shoots towards the optical fiber, and enters the optical fiber when the light point overlaps with the receiving end of the optical fiber; The optical power meter is connected to the transmitting end of the optical fiber and is used for measuring the optical power of the target beam coupled into the optical fiber; The optical power meter, the nutation controller, the double optical wedge scanning system driver, and the double optical wedge scanning system are electrically connected in sequence; The nutation controller is used for calculating the more optimized rotation directions and rotation angles of the two optical wedges according to the optical power feedback measured by the optical power meter, controlling the double optical wedge scanning system driver to apply voltage, and then dynamically optimizing the rotation directions and rotation angles of the two optical wedges; The double optical wedge scanning system driver is used for the linkage control of the two optical wedges.

[0006] In this application, a double optical wedge scanning system, a nutation coupling mirror, and an optical fiber are sequentially arranged along the optical path. The transmitting end of the optical fiber is connected to an optical power meter. The optical power meter, the nutation controller, the double optical wedge scanning system driver, and the double optical wedge scanning system are electrically connected in sequence. The two optical wedges of the double optical wedge scanning system are adjusted to control the nutation scanning of the light spot on the nutation coupling mirror. According to the optical power feedback measured by the optical power meter, the nutation controller calculates the more optimized rotation directions and rotation angles of the two optical wedges, and dynamically optimizes the rotation of the two optical wedges, ensuring high and stable optical output coupling efficiency and reducing power consumption.

[0007] Further, the fiber nutation coupling system based on double optical wedge scanning further includes a communication detector. The communication detector is connected to the transmitting end of the optical fiber and is used for converting the target beam from an optical signal into an electrical signal, and then transmitting the electrical signal to a demodulator for demodulation.

[0008] Further, the fiber nutation coupling system based on double optical wedge scanning further includes a beam splitter. The beam splitter is installed at the transmitting end of the optical fiber. The transmitting end of the optical fiber is connected to the optical power meter and the communication detector respectively through the beam splitter, and is used for splitting the target beam into two beams and transmitting them to the optical power meter and the communication detector respectively.

[0009] Further, the splitting ratio of the beam splitter is 20:80; Among them, 20% of the target beam is transmitted to the optical power meter, and 80% of the target beam is transmitted to the communication detector.

[0010] Further, the optical fiber is a single-mode optical fiber.

[0011] Further, the double optical wedge scanning system includes two optical wedge assemblies, and the two optical wedge assemblies are arranged facing each other; The optical wedge assembly includes: an optical wedge, a lens barrel, a bearing group, a motor, and an encoder; The optical wedge is installed in the lens barrel, and a bearing group is sleeved outside the lens barrel for the rotation of the lens barrel; The motor is connected to the lens barrel, and is used to control the motor to drive the lens barrel to rotate by applying a voltage through the double optical wedge scanning system driver, so as to drive the optical wedge to rotate; The encoder is installed on the lens barrel, and the encoder is electrically connected to the motor for detecting the rotation direction and rotation angle of the optical wedge.

[0012] Further, the fiber nutation coupling system based on double optical wedge scanning further includes a beam expander, and the beam expander is arranged along the optical path on the side of the double optical wedge scanning system away from the nutation coupling mirror for compressing the target beam. When in use, the target beam is incident parallel, compressed by the beam expander, and exits parallel; In this application, the beam expander is used to reduce the light passing aperture, greatly reducing the sizes of the two optical wedges, thereby reducing the sizes of the two optical wedge assemblies, making the structure of the fiber nutation coupling system based on double optical wedge scanning more compact.

[0013] In a second aspect, based on the same inventive concept, the present invention provides a fiber nutation coupling method based on double optical wedge scanning, including: Step 1, control the motors of the two optical wedge assemblies of the double optical wedge scanning system to drive the two optical wedges to rotate in opposite directions and / or in the same direction respectively according to their respective specified speeds and accelerations through the double optical wedge scanning system driver, so as to control the spot to perform nutation scanning on the nutation coupling mirror, and use the nutation coupling mirror to couple the target beam to the optical fiber; Step 2, measure the optical power of the target beam coupled into the optical fiber through an optical power meter; Step 3, based on the optical power feedback measured by the optical power meter, solve for the more optimized rotation direction and rotation angle of the two optical wedges through a nutation controller, and control the double optical wedge scanning system driver to apply a voltage; Step 4: Apply voltages through the dual-wedge scanning system driver to control the motors of the two wedge assemblies to drive the two wedges to rotate in opposite and / or the same directions respectively according to the two more optimized rotation directions and rotation angles calculated by the nutation controller, so as to dynamically optimize the rotation of the two wedges, couple the target beam into the optical fiber by using the nutation coupling mirror, ensure that the optical output coupling efficiency of the target beam coupled into the optical fiber is relatively high and stable, and ensure the stability of communication while reducing power consumption.

[0014] Further, the calculation formulas for the deflection azimuths of the target beam passing through the two wedges of the dual-wedge scanning system in sequence include:

[0015]

[0016] Wherein, is the direction component after the target beam passes through the two wedges in sequence, the direction is the horizontal axis direction preset according to the position of the encoder (i.e., the horizontal direction perpendicular to the incident direction of the target beam), is the direction component after the target beam passes through the two wedges, the and are the rotation angles of the two wedges respectively.

[0017] In the space rectangular coordinate system established on the nutation coupling mirror, within the area where the nutation coupling mirror can receive the target beam to form a light spot, the two rotation angle information of the two wedges in each deflection state is in one-to-one correspondence with the two-dimensional angular coordinates of the target beam.

[0018] Further, the specific content of Step 3 includes: Step 31: Set the control voltage of the motor to the initial voltage, and the specific formula is ; Wherein, is the current control voltage of the motor, is the initial voltage of the motor; Step 32: Set a random perturbation that follows a Bernoulli distribution; Step 33: Superimpose a positive random perturbation on the current control voltage of the motor and output it, and the specific formula is ; Step 34: Calculate the performance evaluation function of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing the positive perturbation, and evaluate the nutation coupling performance after superimposing the positive perturbation. The specific formula is ; where is the nutation coupling performance evaluation parameter of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing the positive perturbation under the current control voltage of the motor, is the nutation coupling performance evaluation parameter of the fiber optic nutation coupling system based on double optical wedge scanning under the current control voltage of the motor; Step 35: Superimpose a negative random perturbation on the current control voltage of the motor and output it. The specific formula is ; Step 36: Calculate the performance evaluation function of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing the negative perturbation, and evaluate the nutation coupling performance after superimposing the negative perturbation. The specific formula is ; where is the nutation coupling performance evaluation parameter of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing the negative perturbation under the current control voltage of the motor; Step 37: Calculate the change amount of the performance evaluation parameter after superimposing the positive random perturbation and the negative random perturbation under the current control voltage of the motor. The specific formula is ; where is the change amount of the performance evaluation parameter after superimposing the positive random perturbation and the negative random perturbation under the current control voltage of the motor; Calculate the optimized voltage of the motor according to the change amount of the performance evaluation parameter. The specific formula is ; where is the optimized voltage of the motor, is the system gain preset according to the feedback of the motor current loop; Update the control voltage of the motor to the optimized voltage; Step 38: Calculate the optical output coupling efficiency of the target beam coupled into the optical fiber according to the optical power measured by the optical power meter. When the optical output coupling efficiency has not reached the maximum, repeat Steps 32 to 37, control the motors of the two optical wedge assemblies to iteratively optimize the voltage in turn until the optical output coupling efficiency of the target beam coupled into the optical fiber reaches the maximum, feedback to control the nutation controller to stop the iteration, and obtain the optimal optimized voltages of the motors of the two optical wedge assemblies respectively. Then, control the double optical wedge scanning system driver to apply the voltage.

[0019] Adopting the above technical solution, the present invention has the following beneficial effects: A fiber optic nutation coupling system and method based on double optical wedge scanning provided by the present invention adjusts the two optical wedges of the double optical wedge scanning system to control the spot to perform nutation scanning on the nutation coupling mirror. According to the optical power feedback measured by the optical power meter, the nutation controller calculates the more optimized rotation directions and rotation angles of the two optical wedges, dynamically optimizes the rotation of the two optical wedges, ensures a high and stable optical output coupling efficiency, and reduces power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of a fiber optic nutation coupling system based on double optical wedge scanning provided by an embodiment of the present invention; Figure 2 It is a flowchart of a fiber optic nutation coupling method based on double optical wedge scanning provided by an embodiment of the present invention; Figure 3 It is a schematic double optical wedge scanning diagram of a double optical wedge scanning system provided by an embodiment of the present invention; Figure 4 It is a spatial rectangular coordinate system diagram established on the nutation coupling mirror for the fiber optic nutation coupling method based on double optical wedge scanning provided by an embodiment of the present invention; Figure 5 It is Figure 2 The flowchart of step 3 shown.

[0022] Reference Numerals: 1 - beam expander; 2 - double optical wedge scanning system; 3 - nutation coupling mirror; 4 - optical fiber; 5 - beam splitter; 6 - optical power meter; 7 - nutation controller; 8 - double optical wedge scanning system driver; 9 - communication detector. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The following further explains and illustrates the present invention in combination with specific embodiments.

[0027] It should also be noted that the following specific embodiments or specific implementation manners are a series of optimized setting manners listed by the present invention to further explain the specific inventive content, and these setting manners can be combined with each other or used in association with each other.

[0028] Embodiment 1 As Figure 1As shown in the figure, a fiber optic nutation coupling system based on double optical wedge scanning provided in this embodiment includes: a double optical wedge scanning system 2, a nutation coupling mirror 3, an optical fiber 4, an optical power meter 6, a nutation controller 7, and a double optical wedge scanning system driver 8; the double optical wedge scanning system 2, the nutation coupling mirror 3, and the optical fiber 4 are arranged in sequence along the optical path. During use, the target beam is incident parallelly and passes through the double optical wedge scanning system 2 and the nutation coupling mirror 3 in sequence, and then shoots towards the optical fiber 4; the target beam is usually free space light; the double optical wedge scanning system 2 is provided with two optical wedges, the vertical surfaces (i.e., the mirror surfaces perpendicular to the optical axis) of the two optical wedges are parallel and face each other, and the wedge surfaces of the two optical wedges face away from each other. During use, the target beam passes through the two optical wedges in sequence and exits from the wedge surface of the optical wedge closer to the nutation coupling mirror 3, irradiating on the nutation coupling mirror 3 to form a light spot. By rotating the two optical wedges in opposite and / or the same direction, a deflected free space optical axis angle is formed, thereby controlling the nutation scanning of the light spot on the nutation coupling mirror 3; the nutation coupling mirror 3 is used for focusing the target beam, and the target beam converges into a light point through the nutation coupling mirror 3 and shoots towards the optical fiber 4, and enters the optical fiber 4 when the light point overlaps with the receiving end of the optical fiber 4; The optical power meter 6 is connected to the emitting end of the optical fiber 4 and is used for measuring the optical power of the target beam coupled into the optical fiber 4; the optical power meter 6, the nutation controller 7, the double optical wedge scanning system driver 8, and the double optical wedge scanning system 2 are electrically connected in sequence; the nutation controller 7 is used for calculating the more optimized rotation directions and rotation angles of the two optical wedges according to the optical power feedback measured by the optical power meter 6, controlling the double optical wedge scanning system driver 8 to apply a voltage, and further dynamically optimizing the rotation directions and rotation angles of the two optical wedges; the double optical wedge scanning system driver 8 is used for the linkage control of the two optical wedges.

[0029] In this application, the double optical wedge scanning system 2, the nutation coupling mirror 3, and the optical fiber 4 are arranged in sequence along the optical path. The emitting end of the optical fiber 4 is connected to the optical power meter 6, and the optical power meter 6, the nutation controller 7, the double optical wedge scanning system driver 8, and the double optical wedge scanning system 2 are electrically connected in sequence. By adjusting the two optical wedges of the double optical wedge scanning system 2 to control the nutation scanning of the light spot on the nutation coupling mirror 3, according to the optical power feedback measured by the optical power meter 6, the nutation controller 7 calculates the more optimized rotation directions and rotation angles of the two optical wedges, and dynamically optimizes the rotation of the two optical wedges, ensuring a high and stable optical output coupling efficiency and reducing power consumption.

[0030] On the basis of the above technical solution, further preferably, the fiber optic nutation coupling system based on double optical wedge scanning further includes a communication detector 9, and the communication detector 9 is connected to the emitting end of the optical fiber 4 and is used for converting the target beam from an optical signal into an electrical signal, and then transmitting the electrical signal to a demodulator for demodulation.

[0031] More preferably, the fiber optic nutation coupling system based on double optical wedge scanning further includes a beam splitter 5, which is installed at the transmitting end of the optical fiber 4. The transmitting end of the optical fiber 4 is connected to the optical power meter 6 and the communication detector 9 respectively through the beam splitter 5, and is used for splitting a target beam into two beams and transmitting them to the optical power meter 6 and the communication detector 9 respectively.

[0032] In this embodiment, the splitting ratio of the beam splitter 5 is 20:80; among them, 20% of the target beam is transmitted to the optical power meter 6, and 80% of the target beam is transmitted to the communication detector 9.

[0033] More preferably, the optical fiber 4 is a single-mode optical fiber, and the mode field diameter (1 / e 2 ) @ 1550 nm: 10.4 μm.

[0034] Further, the double optical wedge scanning system 2 includes two optical wedge assemblies, and the two optical wedge assemblies are arranged facing each other; The optical wedge assembly includes: an optical wedge, a lens barrel, a bearing group, a motor and an encoder; The optical wedge is installed in the lens barrel, and a bearing group is sleeved outside the lens barrel for the rotation of the lens barrel; The motor is connected to the lens barrel and is used to control the motor to drive the lens barrel to rotate by applying a voltage through the double optical wedge scanning system driver 8, so as to drive the optical wedge to rotate; The encoder is installed on the lens barrel, and the encoder is electrically connected to the motor and is used to detect the rotation direction and rotation angle of the optical wedge.

[0035] In this embodiment, the motor is usually a brushless motor such as a DC torque motor or a DC servo motor. Except for the DC torque motor, other types of brushless motors need to drive the lens barrel to rotate by setting corresponding transmission components.

[0036] More preferably, the encoder is usually a grating encoder such as a reflective grating encoder or a transmissive grating encoder. The grating encoder has a fast response and high accuracy, and the measurement accuracy is generally at the micron and arcsecond levels; the grating encoder usually consists of a light source, a main grating, an indicating grating (i.e., a secondary grating) and a detector. The main grating and the indicating grating are installed in parallel and separated. There is a certain rotation angle between the planes where the main grating and the indicating grating are located. After parallel light vertically irradiates the main grating and the indicating grating and diffraction occurs, Moiré fringes will appear, and the displacement can be obtained by measuring the change of the Moiré fringes.

[0037] Moreover, the fiber optic nutation coupling system based on double optical wedge scanning further includes a beam expander 1, which is arranged along the optical path on the side of the double optical wedge scanning system 2 away from the nutation coupling mirror 3 for compressing the target beam. During use, the target beam is incident parallelly, compressed by the beam expander 1, and exits parallelly. In this application, the beam expander 1 is used to reduce the light passing aperture, greatly reducing the sizes of the two optical wedges, thereby reducing the sizes of the two optical wedge assemblies and making the structure of the fiber optic nutation coupling system based on double optical wedge scanning more compact.

[0038] In the present invention, the spot is controlled to perform nutation scanning on the nutation coupling mirror 3 by adjusting the two optical wedges of the double optical wedge scanning system 2. According to the optical power feedback measured by the optical power meter 6, the nutation controller 7 is used to calculate the more optimized rotation directions and rotation angles of the two optical wedges, dynamically optimizing the rotation of the two optical wedges to ensure a relatively high and stable optical output coupling efficiency and reduce power consumption.

[0039] Embodiment 2 As Figures 2 - 5 shown, a fiber optic nutation coupling method based on double optical wedge scanning provided in this embodiment is applied to the fiber optic nutation coupling system based on double optical wedge scanning as described above. The method includes: Step 1: The motors of the two optical wedge assemblies of the double optical wedge scanning system are controlled by the double optical wedge scanning system driver to drive the two optical wedges to rotate in opposite and / or the same direction respectively at their respective specified speeds and accelerations, thereby controlling the spot to perform nutation scanning on the nutation coupling mirror, and coupling the target beam to the optical fiber through the nutation coupling mirror. Step 2: Measure the optical power of the target beam coupled into the optical fiber by the optical power meter. Step 3: According to the optical power feedback measured by the optical power meter, calculate the more optimized rotation directions and rotation angles of the two optical wedges through the nutation controller, and control the double optical wedge scanning system driver to apply voltage. Step 4: The double optical wedge scanning system driver applies voltage to control the motors of the two optical wedge assemblies to drive the two optical wedges to rotate in opposite and / or the same direction respectively at the more optimized rotation directions and rotation angles of the two optical wedges calculated by the nutation controller, thereby dynamically optimizing the rotation of the two optical wedges, ensuring a relatively high and stable optical output coupling efficiency of the target beam coupled into the optical fiber, reducing power consumption while ensuring the stability of communication.

[0040] Referring to Figure 3 shown, more preferably, the calculation formula for the deflection azimuths of the target beam passing through the two optical wedges of the double optical wedge scanning system includes:

[0041]

[0042] Among them, is the direction component after the target beam passes through the two optical wedges in sequence, and the direction is the horizontal axis direction preset according to the position of the encoder (i.e., the horizontal direction perpendicular to the incident direction of the target beam), is the direction component after the target beam passes through the two optical wedges in sequence, and the direction is the vertical axis direction preset according to the position of the encoder (i.e., the vertical direction perpendicular to the incident direction of the target beam), is the wedge angle of the optical wedge, and are the rotation angles of the two optical wedges respectively.

[0043] In this embodiment, the wedge angles of the two optical wedges are equal.

[0044] More preferably, the rotation angle ranges of the two optical wedges are both 0° to 360°.

[0045] Specifically, trigonometric functions are used to resolve the direction component and direction component after the target beam passes through the two optical wedges respectively, and then the deflection azimuth of the target beam passing through the two optical wedges in sequence is calculated by the method of linear superposition. The specific derivation formula is as follows:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051] Among them, is the direction component after the target beam passes through the first optical wedge, is the direction component after the target beam passes through the first optical wedge, is the direction component after the target beam passes through the second optical wedge, is the direction component after the target beam passes through the second optical wedge.

[0052] Refer toFigure 4 As shown, a rectangular coordinate system OXYZ is established on the nutation coupling mirror. In the area on the nutation coupling mirror where the target beam can be received to form a light spot, the two rotation angle information of the two optical wedges in each deflection state is in one-to-one correspondence with the two-dimensional angular coordinates of the target beam ; Referring to Figure 4 as shown, where point O is the position of the light spot where the target beam directly hits the nutation coupling mirror, point A is the incident position of the target beam on the first optical wedge, point B is the position of the light spot where the target beam is refracted on the nutation coupling mirror after passing through the two optical wedges, point C is the component of point B in the X direction, and point D is the component of point B in the Y direction. Referring to Figure 4 as shown , .

[0053] Referring to Figure 5 as shown, more preferably, the specific steps of step 3 include: Step 31: Set the control voltage of the motor to the initial voltage, and the specific formula is ; where is the current control voltage of the motor, is the initial voltage of the motor; In the nutation coupling experiment, the initial voltage is usually the voltage applied by the driver of the double optical wedge scanning system after compensating for the system static error. When the initial voltage is unknown, it is usually set to 0; Step 32: Set a random perturbation whose input follows a Bernoulli distribution ; Step 33: Superimpose a positive random perturbation on the current control voltage of the motor and output it. The specific formula is ; Step 34: Calculate the performance evaluation function of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing the positive perturbation, and evaluate the nutation coupling performance after superimposing the positive perturbation. The specific formula is ; where is the nutation coupling performance evaluation parameter of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing the positive perturbation on the current control voltage of the motor, is the nutation coupling performance evaluation parameter of the fiber optic nutation coupling system based on double optical wedge scanning under the current control voltage of the motor; The initial performance evaluation parameter can be estimated through experience; Step 35: Superimpose a negative random perturbation on the current control voltage of the motor and output it. The specific formula is ; Step 36: Calculate the performance evaluation function of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing negative perturbations, and evaluate the nutation coupling performance after superimposing negative perturbations. The specific formula is ; where is the nutation coupling performance evaluation parameter of the fiber optic nutation coupling system based on double optical wedge scanning after superimposing negative perturbations under the current control voltage of the motor; Step 37: Calculate the change amount of the performance evaluation parameter after superimposing positive random perturbations and negative random perturbations under the current control voltage of the motor. The specific formula is ; where is the change amount of the performance evaluation parameter after superimposing positive random perturbations and negative random perturbations under the current control voltage of the motor; Calculate the optimized voltage of the motor according to the change amount of the performance evaluation parameter. The specific formula is ; where is the optimized voltage of the motor, is the system gain preset according to the feedback of the motor current loop; Update the control voltage of the motor to the optimized voltage; Step 38: Calculate the optical output coupling efficiency of the target beam coupled into the optical fiber according to the optical power measured by the optical power meter. When the optical output coupling efficiency does not reach the maximum, repeat Steps 32 to 37, control the motors of the two optical wedge assemblies to iteratively optimize the voltage in turn until the optical output coupling efficiency of the target beam coupled into the optical fiber reaches the maximum, feedback to control the nutation controller to stop iteration, and obtain the optimal optimized voltages of the motors of the two optical wedge assemblies respectively. Then, control the double optical wedge scanning system driver to apply voltage.

[0054] More preferably, the specific formula for calculating the iteratively optimized voltage of the motor according to the change amount of the performance evaluation function is ; ; ; where is the optimized voltage of the motor of the th optical wedge assembly after iterations, is the optimized voltage of the motor of the th optical wedge assembly after iterations, The system gain at the optimized voltage of the motor of the th optical wedge assembly after iterations, is at the The motor of each of the optical wedge assemblies passes through The change in the performance evaluation function by superimposing positive random perturbations and negative random perturbations under the voltage optimized by the th The motor of each of the optical wedge assemblies passes through The random perturbations superimposed on the voltage optimized by the

[0055] Since the two optical wedges are respectively driven to rotate by the motors of the two optical wedge assemblies, the control voltage of the motor is directly related to the rotation angle. Superimposing a positive random perturbation or a negative random perturbation on the current control voltage of the motor is to control the motor to drive the optical wedge to rotate forward or backward by a certain step angle. Therefore, optimizing the control voltage of the motor is to solve for a more optimized rotation direction and rotation angle of the optical wedge. The rotation direction and rotation angle of the optical wedge during optimization can be detected by the encoder.

[0056] The control process of a fiber optic nutation coupling system based on double optical wedge scanning provided by this application is as follows: First, control the motors of the two optical wedge assemblies to drive the two optical wedges to rotate in opposite and / or the same direction respectively at their respective specified speeds and accelerations, so as to control the light spot to perform a fast and comprehensive scan on the nutation coupling mirror 4 to 5 times. Use the nutation coupling mirror to couple the target beam to the optical fiber, detect whether there is an optical signal coupled into the optical fiber, and feedback control the rotation of the two optical wedges according to the detection information until it is detected that there is an optical signal coupled into the optical fiber; if it is not detected that there is an optical signal coupled into the optical fiber, continuously repeat this process; Second, optionally, based on the feedback information of the optical signal coupled into the optical fiber detected, combined with the fast and comprehensive scan trajectory, roughly estimate the position information of the receiving end of the optical fiber, or obtain the external input position reference information of the optical fiber; according to the position information of the receiving end of the optical fiber, control the motors of the two optical wedge assemblies to drive the two optical wedges to rotate in opposite and / or the same direction respectively at their respective specified speeds and accelerations with a small step angle of 10 arcseconds, so as to control the light spot to perform a preliminary scan on the nutation coupling mirror. Use the nutation coupling mirror to couple the target beam to the optical fiber, detect the optical output coupling efficiency of the target beam coupled into the optical fiber, and feedback control the rotation of the two optical wedges according to the detection information until the optical output coupling efficiency of the target beam coupled into the optical fiber reaches 10%, completing the preliminary coupling; if the optical output coupling efficiency of the target beam coupled into the optical fiber detected does not reach 10%, continuously repeat this process; Then, according to the feedback information of the optical output coupling efficiency of the target beam coupled into the optical fiber, in combination with the fast and comprehensive scanning trajectory, adjust the rotation steps of the two optical wedges, and control the motors of the two optical wedge assemblies to drive the two optical wedges to rotate in opposite and / or the same direction with a small angle step of 2 arcseconds at their respective specified speeds and accelerations, so as to control the spot to scan precisely on the nutation coupling mirror, use the nutation coupling mirror to couple the target beam to the optical fiber, detect the optical output coupling efficiency of the target beam coupled into the optical fiber, and control the rotation of the two optical wedges according to the detected information feedback until the optical output coupling efficiency of the target beam coupled into the optical fiber reaches the maximum or exceeds 50%, completing the precise alignment; if the optical output coupling efficiency of the target beam coupled into the optical fiber is not up to 50%, then repeat this process continuously; Finally, turn on the communication, use the communication detector to convert 80% of the optical signals received by the optical fiber into electrical signals for communication, and at the same time, monitor the optical power of 20% of the target beam coupled into the optical fiber in real time through the optical power meter, calculate the stability of the feedback optical signal of the optical output coupling efficiency based on the optical power, pause the communication when the optical output coupling efficiency is less than 45%, and re-perform the precise scanning process to ensure the stability of the communication.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fiber nutation coupling system based on double wedge scanning, characterized in that: include: Double wedge scanning system, nutation coupling mirror, optical fiber, optical power meter, nutation controller and double wedge scanning system driver; The double wedge scanning system, the nutation coupling mirror and the optical fiber are arranged in sequence along the optical path. When in use, the target light beam is incident in parallel, passes through the double wedge scanning system and the nutation coupling mirror in sequence, and is emitted to the optical fiber. The dual optical wedge scanning system is provided with two optical wedges, the vertical surfaces of the two optical wedges are parallel and arranged facing each other, and the wedge surfaces of the two optical wedges are arranged facing each other, and are used to control the light spot to perform nutation scanning on the nutation coupling mirror by rotating the two optical wedges in opposite directions and / or in the same direction; The nutating coupling mirror is used to focus the target light beam into a light spot and emit it to the optical fiber, and when the light spot overlaps with the receiving end of the optical fiber, it is emitted into the optical fiber; The optical power meter is connected to the transmitting end of the optical fiber and is used to measure the optical power of the target light beam coupled into the optical fiber; The optical power meter, the nutation controller, the dual optical wedge scanning system driver and the dual optical wedge scanning system are electrically connected in sequence; The nutation controller is used to calculate the rotation direction and rotation angle of the two optical wedges according to the optical power feedback measured by the optical power meter, and control the dual optical wedge scanning system driver to apply voltage; The dual optical wedge scanning system driver is used for linkage control of the two optical wedges.

2. The optical fiber nutation coupling system based on double wedge scanning according to claim 1, characterized in that: It also includes a communication detector, which is connected to the emitting end of the optical fiber and is used to convert the target light beam from an optical signal to an electrical signal.

3. The optical fiber nutation coupling system based on double wedge scanning according to claim 2, characterized in that: It also includes a beam splitter, which is installed at the emitting end of the optical fiber. The emitting end of the optical fiber is connected to the optical power meter and the communication detector respectively through the beam splitter, and is used to split the target light beam into two beams, which are transmitted to the optical power meter and the communication detector respectively.

4. The optical fiber nutation coupling system based on double wedge scanning according to claim 3, characterized in that: The beam splitter has a splitting ratio of 20:80, wherein 20% of the target light beam is transmitted to the optical power meter, and 80% of the target light beam is transmitted to the communication detector.

5. The optical fiber nutation coupling system based on double wedge scanning according to claim 1, characterized in that: The optical fiber is a single-mode optical fiber.

6. The optical fiber nutation coupling system based on double wedge scanning according to claim 1, characterized in that: The dual optical wedge scanning system comprises two optical wedge components, and the two optical wedge components are arranged facing each other; The optical wedge assembly comprises: an optical wedge, a lens barrel, a bearing group, a motor and an encoder; The optical wedge is installed in the lens barrel, and a bearing group is mounted on the outer side of the lens barrel for rotating the lens barrel; The motor is connected to the lens barrel and is used to control the motor to drive the lens barrel to rotate through the dual optical wedge scanning system driver to apply voltage, thereby driving the optical wedge to rotate; The encoder is mounted on the lens barrel and is electrically connected to the motor for detecting the rotation direction and rotation angle of the optical wedge.

7. The optical fiber nutation coupling system based on double wedge scanning according to claim 1, characterized in that: It also includes a beam shrinking mirror, which is arranged along the optical path on a side of the double wedge scanning system away from the nutating coupling mirror and is used for compressing the target light beam.

8. A fiber nutation coupling method based on double wedge scanning using the system as claimed in claim 6, characterized in that: include: Step 1: Control the motors of the two optical wedge components of the dual optical wedge scanning system through the dual optical wedge scanning system driver to drive the two optical wedges to rotate in opposite directions and / or in the same direction according to their own specified speeds and accelerations, control the light spot to perform nutation scanning on the nutation coupling mirror, and use the nutation coupling mirror to couple the target light beam to the optical fiber; Step 2, measuring the optical power of the target light beam coupled into the optical fiber by an optical power meter; Step 3, according to the optical power feedback measured by the optical power meter, the nutation controller calculates the more optimized rotation direction and rotation angle of the two optical wedges, and controls the dual optical wedge scanning system driver to apply voltage; Step 4: Apply voltage through the dual optical wedge scanning system driver to control the motors of the two optical wedge assemblies to drive the two optical wedges to rotate in opposite directions and / or in the same direction according to the calculated rotation direction and rotation angle, thereby dynamically optimizing the rotation of the two optical wedges, and using a nutating coupling mirror to couple the target light beam into the optical fiber.

9. The optical fiber nutation coupling method based on double wedge scanning according to claim 8, characterized in that: The calculation formula for the deflection azimuth of the target light beam passing through the two optical wedges of the dual optical wedge scanning system in sequence includes: in, The target beam passes through the two optical wedges in sequence. Directional component, The direction is the horizontal axis direction preset according to the position of the encoder. The target beam passes through two optical wedges in sequence. Directional component, The direction is the longitudinal direction preset according to the position of the encoder. is the wedge angle of the optical wedge, and are the rotation angles of the two optical wedges respectively.

10. The optical fiber nutation coupling method based on double wedge scanning according to claim 8, characterized in that: The step 3 specifically includes: Step 31: Set the control voltage of the motor to the initial voltage. The specific formula is: ; in, is the current control voltage of the motor, is the initial voltage of the motor; Step 32: Set the input to follow the random disturbance of Bernoulli distribution ; Step 33: Superimpose the positive random disturbance on the current control voltage of the motor and output it. The specific formula is: ; Step 34, calculate the performance evaluation function of the optical fiber nutation coupling system based on double wedge scanning after superimposing the forward disturbance, the specific formula is: ; in, is a nutation coupling performance evaluation parameter of the optical fiber nutation coupling system based on double wedge scanning after a forward disturbance is superimposed on the current control voltage of the motor, is a nutation coupling performance evaluation parameter of the optical fiber nutation coupling system based on double wedge scanning under the current control voltage of the motor; Step 35: Superimpose negative random disturbance on the current control voltage of the motor and output it. The specific formula is: ; Step 36, calculate the performance evaluation function of the optical fiber nutation coupling system based on double wedge scanning after superimposing the negative disturbance, the specific formula is: ; in, is a nutation coupling performance evaluation parameter of the optical fiber nutation coupling system based on double wedge scanning after a negative disturbance is superimposed on the current control voltage of the motor; Step 37, calculate the change in the performance evaluation parameter when the positive random disturbance and the negative random disturbance are superimposed under the current control voltage of the motor. The specific formula is: ; in, is the change in the performance evaluation parameter of the motor when the positive random disturbance and the negative random disturbance are superimposed under the current control voltage of the motor; The optimized voltage of the motor is calculated according to the change in the performance evaluation parameter. The specific formula is: ; in, is the optimized voltage for the motor, A system gain preset according to feedback of the motor current loop; Updating the control voltage of the motor to an optimized voltage; Step 38, calculating the optical output coupling efficiency of the target light beam coupled into the optical fiber according to the optical power measured by the optical power meter, repeating steps 32 to 37 when the optical output coupling efficiency has not reached a maximum, controlling the motors of the two optical wedge assemblies to iteratively optimize the voltages in sequence until the optical output coupling efficiency of the target light beam coupled into the optical fiber reaches a maximum, and feedback controlling the nutation controller to stop iteration.

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