A free space optical transmitting and receiving module

Abstract

The invention relates to a free-space optical transmitting and receiving module, comprising a laser transmitting module, an optical circulator, a micro-motion lens and a laser receiving module; the laser transmitting module is used for transmitting laser signals; the optical circulator comprises a first port, a second port and a third port; the laser is input from the first port and then output from the second port, and is input from the second port and then output from the third port; the micro-motion lens is provided with a micro-displacement driver with two degrees of freedom of the X-axis and the Y-axis, or a micro-displacement driver with three degrees of freedom of the X-axis, the Y-axis and the Z-axis; the micro-motion lens of the invention shares a component for transmitting and receiving, thereby reducing errors and improving capture and tracking accuracy; the micro-displacement driver is provided to realize two-dimensional micro-displacement of the micro-motion lens in an XY plane, thereby generating far-field space scanning; on the one hand, the scanning range can be expanded; on the other hand, the micro-displacement driver can be used for receiving signals in a large range at multiple angles, thereby improving receiving accuracy and reducing alignment difficulty.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a free-space optical transmitting and receiving module. Background Art

[0002] In a wireless optical communication system, the communication subsystem and the capture, alignment and tracking subsystem, as well as the capture, alignment and tracking subsystem, do not have a completely co-aperture structure, so it is necessary to ensure the precision coaxiality of multiple optical axes, including: a. capture / coarse tracking detection sight axis coaxiality; b. precision tracking detection sight axis coaxiality; c. communication sight axis coaxiality. Not only is the structure complex, but it will also inevitably lead to great difficulties in the overall design, processing and assembly of the wireless optical communication system, and the cost cannot be reduced.

[0003] In the prior art, a portion of the received communication light energy is separated and used as beacon light energy, thereby completing the capture, alignment, and tracking in the wireless optical communication process. This type of solution can also simplify the structure, reduce and lower the volume, weight, and energy consumption. Since the communication light receiving optical system can only focus a portion of the received light signal onto a photodetector of the micrometer scale, the light energy loss is already large. When a portion is separated for capture, alignment, and tracking, the light signal is further weakened, and it has to be compensated by increasing the intensity of the emitted light, which further increases the weight, volume, and power consumption of the device.

[0004] As for the detection of the detection light beam on a two-dimensional plane, the current common methods usually use mechanical rotation, rotating multi-faceted reflection prisms, or MEMS galvanometer scanning methods. In order to accurately capture and track, high-precision position adjustment and control are required, which places high demands on the adjustment accuracy and control method of the product. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a free-space optical transmitting and receiving module.

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] A free-space optical transmitting and receiving module, comprising:

[0008] A laser emission module, used for emitting laser signals;

[0009] An optical circulator, comprising a first port, a second port and a third port; the first port is used to receive a laser signal emitted by a laser emission module;

[0010] A micro-motion lens is arranged at the second port of the optical circulator, and is used to receive a laser signal entering the second port from the first port and transmitting it to the outside, and / or is used to receive an external laser signal and input it into the second port and then output it from the third port; the micro-motion lens is provided with a micro-displacement driver with two degrees of freedom of the X-axis and the Y-axis, or a micro-displacement driver with three degrees of freedom of the X-axis, the Y-axis and the Z-axis;

[0011] The laser receiving module is arranged at the third port of the optical circulator and is used for receiving the laser signal input from the second port.

[0012] Furthermore, the laser emission module includes an emission optical fiber; a micro-displacement driver with two degrees of freedom, X-axis and Y-axis, is provided on the end of the emission optical fiber.

[0013] Furthermore, the laser receiving module includes a receiving optical fiber; a micro-displacement driver with two degrees of freedom, X-axis and Y-axis, is provided on the end of the receiving optical fiber.

[0014] Furthermore, the optical circulator includes a first polarization beam splitter prism, a rotator, and a second polarization beam splitter prism arranged along the optical path; a filter is provided on the side of the first polarization beam splitter prism opposite to the third port.

[0015] Furthermore, a power amplification module is provided between the laser emission module and the optical circulator.

[0016] Furthermore, a low-noise optical preamplifier is provided between the laser receiving module and the optical circulator.

[0017] Furthermore, the micro-displacement driver is driven by piezoelectric ceramics or a piezoelectric motor.

[0018] Furthermore, a self-collimating lens or a beam expander is provided at the output end of the micro-motion lens.

[0019] Furthermore, a first collimating lens is provided in both the laser emitting module and the laser receiving module.

[0020] The beneficial effects of the present invention are as follows: the micro-motion lens is used as a transmitting and receiving end, on the one hand, for transmitting laser signals to the outside, and on the other hand, for receiving external laser signals. Since the transmitting and receiving share a component, the error can be reduced and the capture and tracking accuracy can be improved; by setting a micro-displacement driver, the two-dimensional micro-displacement of the micro-motion lens in the XY plane can be realized to generate far-field spatial scanning; the micro-displacement driver can realize the displacement from nanometer level to micrometer level, and the angle change of the output light beam of the micro-motion lens is formed by the generation of micro-displacement on the focal plane or the virtual focal plane, which can expand the scanning range on the one hand, and can be used for multi-angle and large-range signal reception on the other hand, improve the receiving accuracy and reduce the alignment difficulty; by increasing the freedom of movement of the Z axis, the zoom effect can be achieved. When receiving the laser signal, the micro-motion lens moves in the Z axis direction. In the early capture and positioning process, the micro-motion lens can be moved along the right side of the Z axis to increase the capture area and realize rapid alignment capture. After the capture, the micro-motion lens is moved along the left side of the Z axis to reduce the light beam, improve the energy utilization rate, and improve the efficiency; by moving the micro-motion lens in the Z axis direction, the angular state of the light beam is changed, and the capture efficiency and energy utilization rate are effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic structural diagram of an embodiment of the present invention;

[0023] Figure 2 It is a structural schematic diagram of another embodiment of the present invention;

[0024] Figure 3 It is a structural schematic diagram of another embodiment of the present invention;

[0025] Figure 4 Schematic diagram of the optical path of the micro-motion lens of the present invention moving along the Z axis;

[0026] Description of reference numerals:

[0027] 100, laser emitting module; 101, first collimating lens; 110, emitting optical fiber; 120, power amplifying module; 200, optical circulator; 201, first port; 202, second port; 203, third port; 210, first polarization beam splitter prism; 220, optical rotator; 230, second polarization beam splitter prism; 240, filter; 300, micro-motion lens; 301, focal plane; 400, laser receiving module; 410, receiving optical fiber; 420, low-noise optical preamplifier; 500, beam expander; 500', self-collimating lens. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] like Figure 1As shown, a free-space optical transmitting and receiving module includes a laser transmitting module 100, an optical circulator 200, a micro-motion lens 300, and a laser receiving module 400; the laser transmitting module 100 is used to transmit a laser signal; the optical circulator 200 includes a first port 201, a second port 202, and a third port 203; the laser is input from the first port 201 and then output from the second port 202, and is input from the second port 202 and then output from the third port 203; the first port 201 is usually used to receive the laser signal emitted by the laser transmitting module 100; the Y-axis direction in the figure is actually perpendicular to the paper direction, and the Y-axis direction in the figure is only for illustration;

[0032] The micro-motion lens 300 is used as a transmitting and receiving end, and is used to transmit laser signals to the outside on the one hand, and to receive external laser signals on the other hand. Since the transmitting and receiving share a component, the error can be reduced and the capture and tracking accuracy can be improved; the micro-motion lens 300 can be set as a collimating lens to emit collimated light;

[0033] In one embodiment, the micro-motion lens 300 can be configured as a converging lens, and a self-collimating lens 500' is additionally provided at the output end of the micro-motion lens 300 to ensure the collimation of the output laser. The converging lens can also converge the laser signal incident from the outside after being captured to reduce the light beam and reduce the difficulty of capturing.

[0034] In one embodiment, the micro-motion lens 300 can be configured as a converging lens, and a beam expander 500 is additionally provided at the output end of the micro-motion lens 300. The beam expander 500 can increase the coverage of the output laser signal and can capture the laser signal in a large range, thereby reducing the difficulty of capture.

[0035] The micro-displacement driver of two independent degrees, X-axis and Y-axis, is provided on the micro-motion lens 300. By providing the micro-displacement driver, the micro-motion lens 300 can be subjected to two-dimensional micro-displacement in the XY plane to generate far-field spatial scanning; the micro-displacement driver can achieve displacement from nanometer level to micrometer level, and the micro-displacement on the focal plane 301 or the virtual focal plane 301 is generated to form an angle change of the output light beam of the micro-motion lens 300, which can expand the scanning range on the one hand, and can be used for receiving signals in a large range of multiple angles on the other hand, thereby improving the receiving accuracy and reducing the difficulty of alignment;

[0036] In one embodiment, the micro-movement lens 300 is provided with a micro-displacement driver with three degrees of freedom in the X-axis, Y-axis and Z-axis; by increasing the degree of freedom of movement in the Z-axis, a zoom effect can be achieved; the micro-movement lens 300 is configured as a converging lens, and a collimating lens is additionally provided at the exit end of the micro-movement lens 300; Figure 4As described, in the B state, the autocollimator lens 500 emits collimated light; when the micro-motion lens 300 moves along the right side of the Z axis, the output light of the auto-collimator lens 500' is in the A state, and the range of the output light is larger, which can achieve a large range of scanning and realize the effect of a beam expander; when the micro-motion lens 300 moves along the left side of the Z axis, the output light of the auto-collimator lens 500' is in the C state, which can reduce the light beam and improve the energy utilization rate; similarly, when receiving laser signals, the micro-motion lens 300 moves in the Z axis direction. In the early capture and positioning process, the micro-motion lens 300 can be moved along the right side of the Z axis to increase the capture area and realize rapid alignment and capture. After the capture, the micro-motion lens 300 is moved along the left side of the Z axis to reduce the light beam, improve the energy utilization rate, and improve the efficiency; by moving the micro-motion lens 300 in the Z axis direction, the angular state of the light beam is changed, and the capture efficiency and energy utilization rate are effectively improved; the movement of the micro-motion lens 300 in the X-axis and Y-axis directions is used to realize surface scanning;

[0037] In one embodiment, the laser emitting module 100 includes an emitting optical fiber 110; a micro-displacement driver with two degrees of freedom in the X-axis and the Y-axis is provided at the end of the emitting optical fiber 110;

[0038] In one embodiment, the laser receiving module 400 includes a receiving optical fiber 410; a micro-displacement driver with two degrees of freedom in the X-axis and the Y-axis is provided on the end of the receiving optical fiber 410; it is better to provide the micro-displacement driver on the receiving optical fiber 410 than on the transmitting optical fiber 110, and the micro-displacement driver is used to control the individual scanning movement of the receiving optical fiber 410, and the micro-displacement of the micro-motion lens 300 can achieve faster laser signal capture; since the optical fiber end is highly sensitive to movement, in order to take into account stability and scanning range, the movement range of the micro-displacement driver provided on the transmitting optical fiber 110 will be limited to a smaller range;

[0039] In one embodiment, the micro-displacement driver is driven by piezoelectric ceramics or piezoelectric motors; piezoelectric ceramics are usually pasted on the surface of the micro-motion lens 300 in a sheet structure, and the output displacement of the piezoelectric ceramics is controlled by controlling the change of voltage or current, thereby realizing the micro-displacement of the micro-motion lens 300; when the micro-displacement driver is a micro-displacement driver with two degrees of freedom, the X-axis and the Y-axis, two piezoelectric ceramics are provided to control the micro-displacement of the micro-motion lens 300 in the X-axis and Y-axis directions respectively; similarly, when the micro-displacement driver is a micro-displacement driver with three degrees of freedom, the X-axis, the Y-axis and the Z-axis, three piezoelectric ceramics are provided to control the micro-displacement of the micro-motion lens 300 in the X-axis, the Y-axis and the Z-axis directions respectively, and the displacement in each direction can be controlled separately;

[0040] In one embodiment, the piezoelectric ceramic sheet can be replaced with a piezoelectric motor to form a micro-displacement driver; multiple piezoelectric motors can be provided to achieve displacement control in multiple directions; in one embodiment, since the piezoelectric motor can achieve rotational motion, and the rotational motion also includes the motion of two degrees of freedom of the X-axis and the Y-axis, when only one piezoelectric motor is provided in one embodiment, the two degrees of freedom of the micro-motion lens 300 in the XY plane can also be achieved; the piezoelectric motor, as a precision piezoelectric device, has a core working principle based on the inverse piezoelectric effect of piezoelectric materials. This effect allows piezoelectric materials to undergo slight deformations, i.e., slight vibrations, under the action of an external electric field. In a piezoelectric motor, the stator is usually made of piezoelectric material, and when a voltage signal of a specific frequency is applied, the stator will generate slight vibrations within this frequency range. These tiny vibrations are cleverly converted into macroscopic motions of the mover (micro-motion lens 300) through a carefully designed structure and friction. Whether it is linear motion or rotational motion, the piezoelectric motor can drive the mover to achieve the expected macroscopic motion through the slight vibration of the stator through a series of complex mechanical conversions. For example, among the many designs of piezoelectric motors, the L1B2 piezoelectric motor is a typical example. Its design feature is that through precise structural adjustment, the frequencies of the first-order extension mode and the second-order bending mode of the piezoelectric motor are very close. When a driving signal of a specific frequency is externally loaded, the first-order extension vibration and the second-order bending vibration of the stator will couple with each other to form an elliptical motion trajectory of the friction head. During this elliptical motion, a strong squeezing effect will be generated between the friction head of the stator and the mover. This squeezing effect is further enhanced by the action of the preload, thereby generating a sufficiently large friction force between the two. This friction force is the main source of power to drive the mover to move, allowing the mover to achieve precise linear or rotational motion under the drive of the piezoelectric motor.

[0041] Similarly, the micro-displacement actuators provided on the transmitting optical fiber 110 and the receiving optical fiber 410 can be driven by the above-mentioned solution;

[0042] In one embodiment, the optical circulator 200 includes a first polarization beam splitter prism 210, a polarization plate 220, and a second polarization beam splitter prism 230 arranged along the optical path direction; a filter 240 is provided on the side of the first polarization beam splitter prism 210 opposite to the third port 203; the optical circulator 200 part generates a Tx (transmitting signal) and Rx crosstalk (receiving signal) of more than 60 dB; the filter 240 generates a λ1 and λ2 isolation of more than 40 dB, and the entire system has a Tx and Rx crosstalk of more than 100 dB;

[0043] like Figure 2 As shown, in one embodiment, a first collimating lens 101 is provided in both the laser emitting module 100 and the laser receiving module 400;

[0044] like Figure 3 As shown, in one embodiment, a power amplifier module 120 is provided between the laser transmitting module 100 and the optical circulator 200; a low-noise optical preamplifier 420 is provided between the laser receiving module 400 and the optical circulator 200; after Rx enters the optical fiber low-noise preamplifier, subsequent signal preprocessing is performed to determine alignment.

[0045] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A free space optical transmitting and receiving module, characterized in that: include: A laser emission module (100), used for emitting a laser signal; An optical circulator (200), comprising a first port (201), a second port (202) and a third port (203); the first port (201) is used to receive a laser signal emitted by a laser emission module (100); A micro-motion lens (300) is arranged at the second port (202) of the optical circulator (200), and is used for receiving a laser signal that enters the second port (202) from the first port (201) and outputs the laser signal, and transmitting the laser signal to the outside, and / or for receiving an external laser signal, and inputting the laser signal into the second port (202) and outputting the signal from the third port (203); the micro-motion lens (300) is provided with a micro-displacement driver with two degrees of freedom, namely, an X-axis and a Y-axis, or a micro-displacement driver with three degrees of freedom, namely, an X-axis, a Y-axis and a Z-axis; The laser receiving module (400) is arranged at the third port (203) of the optical circulator (200) and is used to receive the laser signal input from the second port (202).

2. A free-space optical transmitting and receiving module according to claim 1, characterized in that: The laser emission module (100) comprises an emission optical fiber (110); a micro-displacement driver with two degrees of freedom, X-axis and Y-axis, is arranged at the end of the emission optical fiber (110).

3. A free-space optical transmitting and receiving module according to claim 1, characterized in that: The laser receiving module (400) comprises a receiving optical fiber (410); a micro-displacement driver with two degrees of freedom, X-axis and Y-axis, is arranged at the end of the receiving optical fiber (410).

4. A free-space optical transmitting and receiving module according to claim 1, characterized in that: The optical circulator (200) comprises a first polarization beam splitter prism (210), an optical rotator (220), and a second polarization beam splitter prism (230) arranged along the direction of the optical path; a filter (240) is provided on the side of the first polarization beam splitter prism (210) opposite to the third port (203).

5. A free-space optical transmitting and receiving module according to claim 1, characterized in that: A power amplification module (120) is provided between the laser emission module (100) and the optical circulator (200).

6. A free-space optical transmitting and receiving module according to claim 1, characterized in that: A low-noise optical preamplifier (420) is provided between the laser receiving module (400) and the optical circulator (200).

7. A free-space optical transmitting and receiving module according to claim 1, characterized in that: The micro-displacement driver is driven by piezoelectric ceramics or a piezoelectric motor.

8. The free-space optical transmitting and receiving module according to claim 1, characterized in that: The output end of the micro-motion lens (300) is provided with a self-collimating lens (500') or a beam expander (500).

9. A free-space optical transmitting and receiving module according to claim 1, characterized in that: A first collimating lens (101) is provided in both the laser emitting module (100) and the laser receiving module (400).

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