Cross-medium laser communication device and method for adaptively switching communication wavelength

Abstract

The invention discloses a cross-medium laser communication device and method for adaptively switching communication wavelengths. The device comprises a main communication system, a laser transmission device and a field-of-view capturing device. The main communication system comprises a main controller and laser emitters, and the main controller analyzes communication requirements, selects the corresponding laser emitter and emits a laser emission control signal; the number of the laser emitters is at least two, the laser emitters can emit laser with different wavelengths, and the laser emitters emit the laser with the corresponding wavelength to the laser transmission device. The laser transmission device collimates and expands the laser beam and emits the laser beam to the distance. And the view field capturing device finds and aligns with the opposite terminal through the detection device, and adjusts the laser transmission device to align the laser transmitted by the laser transmission device with the opposite terminal. According to the invention, two sets of independent laser communication transceiving systems are highly integrated in a single device by adopting one terminal with two functions, so that the size, the weight and the power consumption of the system are reduced, and convenience is provided for constructing multi-platform cross-domain communication.

Description

Technical Field

[0001] This invention belongs to the field of laser communication, and specifically relates to a cross-medium laser communication device and method that can adaptively switch communication wavelengths according to the usage scenario. Background Technology

[0002] Maritime cross-domain communication technology is a key technology supporting "distributed maritime operations" and an information link for joint operations across all domains. Its development, progress, and level directly impact the PLA's combat capabilities in future high-end warfare. However, underwater-to-surface cross-domain communication is challenging, and research progress has been relatively slow. For a considerable period, submarines have struggled to integrate into the combat system in real time, often operating independently. As underwater overall warfare evolves towards a more systematic approach involving manned / unmanned underwater swarms and underwater / surface formations, achieving high-speed interconnection between manned / unmanned underwater platforms, especially overcoming cross-domain communication barriers between underwater platforms and surface and air platforms, is of significant military importance and urgency.

[0003] Seawater provides a natural cover for underwater platforms, but it also greatly complicates the communication between underwater platforms and the outside world. Due to the absorption effect of seawater on radio waves, the transmission distance of radio frequency in seawater is very limited, and underwater acoustic technology is difficult to achieve cross-media transmission. Current communication between underwater platforms includes acoustic communication and optical communication; cross-media communication technology systems include relay node communication, acoustic-to-radio frequency communication and wireless optical communication.

[0004] Laser communication boasts advantages such as high bandwidth, high speed, cross-medium capability, strong directivity, and resistance to electromagnetic interference. However, in cross-medium communication, existing equipment struggles to dynamically adapt to vastly different channel characteristics within a single communication terminal. For example, in underwater and air-to-ground laser communication, the 1550nm wavelength of air-to-ground laser communication equipment exhibits low atmospheric loss, making it suitable for long-distance communication between air and ground, but it struggles to effectively penetrate the water interface for cross-domain communication. Conversely, the 450nm blue light wavelength of underwater laser communication equipment experiences minimal attenuation underwater, effectively increasing transmission depth after crossing media, but it is unsuitable for air-to-ground transmission. Therefore, when using laser communication equipment for both underwater and air-to-ground communication, two independent single-wavelength laser communication devices are required, which presents certain limitations. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a cross-medium laser communication device and method with adaptive switching of communication wavelengths. It adopts a "one terminal, two functions" approach to highly integrate two independent laser communication transceiver systems into a single device, greatly reducing the system's size, weight, and power consumption, and facilitating the construction of cross-domain communication across multiple platforms.

[0006] The objective of this invention is achieved through the following technical solution: an adaptively switching communication wavelength cross-medium laser communication device, comprising:

[0007] The main communication system, laser transmission equipment, and field-of-view capture equipment communicate with each other via wired or wireless connections.

[0008] The main communication system includes a main controller and laser transmitters. The main controller analyzes the communication requirements, selects the corresponding laser transmitter, and transmits laser transmission control signals to it. There are at least two laser transmitters, each capable of emitting lasers of different wavelengths. The laser transmitters transmit lasers of the corresponding wavelengths to the laser transmission equipment according to the control signals from the main control system.

[0009] The laser transmission equipment collimates and expands the laser beam to form a concentrated beam with a small divergence angle, which is then emitted to a distance; at the same time, it collects the optical signals transmitted from the other party's terminal.

[0010] The field-of-view acquisition device detects and aligns with the target terminal through the detection device, and sends control commands to the laser transmission device based on the target terminal's position, adjusting the laser transmission device to align its transmitted laser with the target terminal.

[0011] Preferably, the main communication system also includes:

[0012] The signal processing and driving unit is wired to the main controller. It converts the digital signals transmitted from the main controller into the current signals required to drive the corresponding laser and sends them to the laser.

[0013] A wavelength division multiplexer, connected after a laser, combines light of different wavelengths from different lasers into a single optical fiber for transmission, and separates the light of different wavelengths received at the receiving end into the corresponding communication detectors.

[0014] An optical circulator, connected after the wavelength division multiplexer, is connected to the telescope system of the laser transmission equipment. The laser transmitted by the wavelength division multiplexer passes unidirectionally through the optical circulator and is then emitted by the telescope system, while the received light is guided to the receiving circuit.

[0015] The communication detector, located after the optical circulator, receives the laser signal from the external source received by the optical circulator, converts the received optical signal into an electrical signal, and sends it to the signal processing and decoding unit.

[0016] The signal processing and decoding unit, located after the communication detector, converts the electrical signals sent by the optical circulator into digital signals and sends them back to the main controller.

[0017] Preferably, the main controller is an FPGA or an ASIC.

[0018] Preferably, the laser emitter includes at least one 450nm laser and one 1550nm laser.

[0019] Preferably, the laser transmission device uses a telescope system.

[0020] Preferably, the field-of-view acquisition device includes a wide field-of-view camera that uses a large field of view to "search" for the other party's beacon light. The wide field-of-view camera employs a zoom design to capture the beacon light at a large divergence angle and to track the beacon light at a small divergence angle.

[0021] Preferably, the cross-medium laser communication device with adaptive switching of communication wavelength further includes an error compensation system, which includes:

[0022] The inertial measurement unit senses the attitude changes of its own platform, connects to the APT controller, and transmits the platform attitude change information to the APT controller.

[0023] The error detection device is connected to the laser transmission device and the APT controller. By detecting the energy distribution of the laser spot on the photosensitive surface of the laser transmission device, it generates an extremely high-precision angle error signal and provides real-time feedback to the APT controller on the deviation between the center of the spot and the theoretical center.

[0024] The beam adjustment element is connected to the free space channel, the laser transmission device, and the APT controller. According to the instructions of the APT controller, it rapidly and slightly adjusts the emission angle of the laser beam of the laser transmission device in two dimensions through the free space channel, and tracks the emission angle of the laser beam of the laser transmission device in real time.

[0025] The APT controller communicates bidirectionally with the main controller, receives error signals from the detector and sensors, runs the control algorithm, calculates the required correction amount, and drives the beam adjustment element to perform compensation.

[0026] Preferably, the error detection device uses a four-quadrant detector.

[0027] Preferably, the beam adjustment element is a high-bandwidth, small-angle beam deflection device driven by a piezoelectric ceramic or a voice coil motor.

[0028] In addition to providing a cross-medium laser communication device with adaptively switching communication wavelengths, this invention also provides a method for achieving cross-medium laser communication with adaptively switching communication wavelengths using the aforementioned device. The method is as follows:

[0029] Upon receiving a communication request, the main controller parses the command and, based on the communication target and environment, selects and switches to the corresponding channel to issue a link establishment command. In the initial stage of link establishment, the field-of-view acquisition device searches for the beacon light of the other party's terminal to achieve initial discovery and alignment, bringing the other party's terminal into the field of view. After stable tracking is completed, the communication link maintenance stage begins. Both parties encode and modulate the communication service data, perform electro-optical conversion, and then select different wavelengths of laser as carriers for mutual transmission according to different media. When the laser beam loaded with information is transmitted to the receiver through free space, the receiver performs photoelectric conversion and decoding to recover the original service data information, completing the information exchange.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] This invention provides a cross-medium laser communication method that can adaptively switch communication wavelengths according to the usage scenario. It utilizes the advantages of laser communication, such as high bandwidth, high speed, cross-medium capability, strong directivity, and resistance to electromagnetic interference, to achieve cross-domain interconnection of information.

[0032] This invention proposes a full-duplex laser communication method and integrated device based on adaptive switching between 1550nm and 450nm dual wavelengths for air and sea cross-medium communication scenarios, overcoming the limitations of current single-wavelength laser communication technology in multi-platform communication such as air and submarine communication. By using the device provided by this invention, different transmission scenarios can be met within a single laser communication terminal according to information transmission needs. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the architecture of a cross-medium laser communication device that adaptively switches communication wavelengths, as described in an embodiment of the present invention. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0035] The present invention provides a cross-medium laser communication device with adaptive switching of communication wavelength, characterized in that: the device includes:

[0036] The main communication system, laser transmission equipment, and field-of-view capture equipment communicate with each other via wired or wireless connections.

[0037] The main communication system includes a main controller and laser transmitters. The main controller analyzes the communication requirements, selects the corresponding laser transmitter, and transmits laser transmission control signals to it. There are at least two laser transmitters, each capable of emitting lasers of different wavelengths. The laser transmitters transmit lasers of the corresponding wavelengths to the laser transmission equipment according to the control signals from the main control system.

[0038] Laser transmission equipment collimates and expands the laser beam to form a concentrated beam with a small divergence angle, which is then emitted to a distance; at the same time, it collects the optical signals transmitted from the other party's terminal.

[0039] The field-of-view acquisition device detects and aligns with the target terminal through the detection device, and sends control commands to the laser transmission device based on the target terminal's position, adjusting the laser transmission device to align its transmitted laser with the target terminal.

[0040] In one embodiment of the present invention, the main communication system further includes:

[0041] The signal processing and driving unit is wired to the main controller and converts the digital signals transmitted from the main controller into the current signals required to drive the corresponding lasers and sends them to the lasers.

[0042] A wavelength division multiplexer, connected after a laser, combines light of different wavelengths from different lasers into a single optical fiber for transmission, and separates the light of different wavelengths received at the receiving end into corresponding communication detectors;

[0043] An optical circulator is connected after the wavelength division multiplexer and to the telescope system of the laser transmission equipment. The laser transmitted by the wavelength division multiplexer passes through the optical circulator in one direction and is then emitted by the telescope system. At the same time, the received light is guided to the receiving circuit.

[0044] The communication detector, located after the optical circulator, receives the laser signal from the external source received by the optical circulator, converts the received optical signal into an electrical signal, and sends it to the signal processing and decoding unit.

[0045] The signal processing and decoding unit, located after the communication detector, converts the electrical signals sent by the optical circulator into digital signals and sends them back to the main controller.

[0046] In one embodiment of the present invention, the main controller is an FPGA or an ASIC.

[0047] In one embodiment of the present invention, the laser emitter includes at least one 450nm laser and one 1550nm laser.

[0048] In one embodiment of the present invention, the laser transmission device employs a telescope system.

[0049] In one embodiment of the present invention, the field-of-view acquisition device includes a wide field-of-view camera that uses a large field of view to "search" for the beacon light of the other party. The wide field-of-view camera adopts a zoom design to capture the beacon light at a large divergence angle and to track the beacon light at a small divergence angle.

[0050] In one embodiment of the present invention, the cross-medium laser communication device with adaptive switching communication wavelength further includes an error compensation system, the error compensation system comprising:

[0051] The inertial measurement unit senses the attitude changes of its own platform, connects to the APT controller, and transmits the platform attitude change information to the APT controller.

[0052] The error detection device is connected to the laser transmission device and the APT controller. By detecting the energy distribution of the laser spot on the photosensitive surface of the laser transmission device, it generates an extremely high-precision angle error signal and feeds back the deviation between the center of the spot and the theoretical center to the APT controller in real time.

[0053] The beam adjustment element is connected to the free space channel, the laser transmission device, and the APT controller. According to the instructions of the APT controller, it rapidly and slightly adjusts the emission angle of the laser beam of the laser transmission device in two dimensions through the free space channel, and tracks the emission angle of the laser beam of the laser transmission device in real time.

[0054] The APT controller communicates bidirectionally with the main controller, receives error signals from the detector and sensors, runs the control algorithm, calculates the required correction amount, and drives the beam adjustment element to perform compensation.

[0055] In one embodiment of the present invention, the error detection device employs a four-quadrant detector.

[0056] In one embodiment of the invention, the beam adjustment element employs a high-bandwidth, small-angle beam deflection device driven by a piezoelectric ceramic or a voice coil motor.

[0057] In one specific embodiment of the present invention, a full-duplex laser communication device with adaptive switching between 1550nm and 450nm wavelengths is provided, such as... Figure 1 As shown, the device includes: a main controller, signal processing and drive, a 1550nm laser, a 450nm laser, a wavelength division multiplexer, an optical circulator, a communication detector, a telescope system, a fast-reflecting mirror, a four-quadrant detector, a coarse-heeled wide-field-of-view camera, an ATP controller, and an inertial measurement unit. The functions of each main component are described below:

[0058] 1) Main controller: The brain of the entire system. It runs high-level communication protocols, coordinates the work of all modules, including adaptive wavelength switching, data flow management, communication with the APT subsystem, etc., and controls the operation of the entire system.

[0059] 2) Signal Processing and Driving: Processing the digital signals from the main controller, including encoding and modulation, and generating the current signals required to drive the corresponding laser.

[0060] 3) 1550nm laser: Generates 1550nm band laser light for atmospheric communication. This band experiences low transmission loss in the atmosphere, making it suitable for long-distance communication with aircraft, satellites, and other airborne platforms.

[0061] 4) 450nm laser: Generates blue laser light for underwater communication. Blue light has the strongest penetrating power in seawater and can effectively penetrate the water-air interface to establish a link with the submersible.

[0062] 5) Wavelength division multiplexer: It can combine two beams of light of different wavelengths from different lasers into a single optical fiber for transmission, or separate different wavelengths of light received at the receiving end to the corresponding detectors.

[0063] 6) Optical circulator: A multi-port non-reciprocal optical device that allows emitted laser light to pass unidirectionally through a telescope system and then be emitted again, while simultaneously guiding the received light to the receiving circuitry to prevent strong transmitted signals from damaging the sensitive receiving detector. It is a key component for realizing full-duplex communication and integrated transceiver operation.

[0064] 7) Communication detector: Used to receive the laser signal source and convert the received optical signal into an electrical signal.

[0065] 8) Telescope system: responsible for collimating and expanding the laser beam to form a beam with concentrated energy and small divergence angle for emission into the distance; at the same time, it collects extremely weak light signals from the other party's terminal and focuses them onto the detector.

[0066] 9) Fast-reflecting mirror: A high-bandwidth, small-angle beam deflection device driven by piezoelectric ceramics or voice coil motors, used to quickly and slightly adjust the emission angle of the laser beam in two dimensions according to the instructions of the APT controller, and to compensate for platform shaking and beam drift in real time.

[0067] 10) Quadrant detector: The core sensor of the precision tracking loop. It generates an extremely high-precision angle error signal by detecting the energy distribution of the light spot on its photosensitive surface, and provides real-time feedback on the deviation between the center of the light spot and the theoretical center.

[0068] 11) Coarse Tracking with Wide Field of View Camera: In the initial stage of link establishment, due to the large initial position uncertainty of both platforms, the laser beam may not directly fall on the other party's receiver. The acquisition unit uses a wide field of view to "search" for the other party's beacon light (in this invention, to compress volume and space as much as possible, a zoom design is used to achieve beacon acquisition at large divergence angles and tracking at small divergence angles), achieving initial detection and alignment, and bringing the other party's terminal into the field of view of the fine tracking unit.

[0069] 12) APT Controller: The "brain" of the APT system. It receives error signals from various detectors and sensors, runs complex control algorithms (such as PID control and Kalman filtering), calculates the required correction amount, and drives the actuator (fast-reflecting mirror) to perform compensation. In this embodiment, the APT controller uses a high-performance DSP.

[0070] 13) Inertial Measurement Unit: Sensing the attitude changes of its own platform to assist in the pointing and stabilization of the beam.

[0071] In this embodiment, when the system needs to communicate with an airborne platform, the main controller commands the wavelength selection switch to activate the 1550nm laser, and the beam is directed towards the airborne target via the telescope system. When communication with an underwater vehicle is required, the system switches to a 450nm laser. Throughout the process, the environmental awareness module continuously provides feedback on channel quality. If the current link quality deteriorates (e.g., due to increased atmospheric turbulence or the underwater vehicle descending), the main controller automatically determines and adjusts the transmission power to maintain link connectivity. All communications are full-duplex, meaning data can be sent and received simultaneously.

[0072] In addition to providing a cross-medium laser communication device with adaptively switching communication wavelengths, this invention also provides a method for achieving cross-medium laser communication with adaptively switching communication wavelengths using the aforementioned device. The method is as follows:

[0073] Upon receiving a communication request, the main controller parses the command and, based on the communication target and environment, selects and switches to the corresponding channel to issue a link establishment command. In the initial stage of link establishment, due to significant initial positional uncertainty between the two platforms, the laser beam may not directly fall on the other party's receiver. The acquisition unit utilizes a large field of view to "search" for the other party's beacon light (in this design, to minimize volume and space, a zoom design is used to capture the beacon at large divergence angles and track it at small divergence angles), achieving initial detection and alignment, bringing the other party's terminal into the field of view of the fine tracking unit. After stable tracking is achieved, the communication link maintenance phase begins. At this time, both parties encode and modulate the communication service data, perform electro-optical conversion, and transmit it to each other using laser as the carrier. When the laser beam loaded with information is transmitted to the receiver via free space, the receiver performs photoelectric conversion and decoding to recover the original service data information, completing the information exchange.

[0074] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cross-medium laser communication device with adaptive switching of communication wavelength, characterized in that: The device includes: The main communication system, laser transmission equipment, and field-of-view capture equipment communicate with each other via wired or wireless connections. The main communication system includes a main controller and laser transmitters. The main controller analyzes the communication requirements, selects the corresponding laser transmitter, and transmits laser transmission control signals to it. There are at least two laser transmitters, each capable of emitting lasers of different wavelengths. The laser transmitters transmit lasers of the corresponding wavelengths to the laser transmission equipment according to the control signals from the main control system. Laser transmission equipment collimates and expands the laser beam to form a concentrated beam with a small divergence angle, which is then emitted to a distance; at the same time, it collects the optical signals transmitted from the other party's terminal. The field-of-view acquisition device detects and aligns with the target terminal through the detection device, and sends control commands to the laser transmission device based on the target terminal's position, adjusting the laser transmission device to align its transmitted laser with the target terminal.

2. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 1, characterized in that: The main communication system also includes: The signal processing and driving unit is wired to the main controller and converts the digital signals transmitted from the main controller into the current signals required to drive the corresponding lasers and sends them to the lasers. A wavelength division multiplexer, connected after a laser, combines light of different wavelengths from different lasers into a single optical fiber for transmission, and separates the light of different wavelengths received at the receiving end into corresponding communication detectors; An optical circulator is connected after the wavelength division multiplexer and to the telescope system of the laser transmission equipment. The laser transmitted by the wavelength division multiplexer passes through the optical circulator in one direction and is then emitted by the telescope system. At the same time, the received light is guided to the receiving circuit. The communication detector, located after the optical circulator, receives the laser signal from the external source received by the optical circulator, converts the received optical signal into an electrical signal, and sends it to the signal processing and decoding unit. The signal processing and decoding unit, located after the communication detector, converts the electrical signals sent by the optical circulator into digital signals and sends them back to the main controller.

3. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 1, characterized in that: The main controller is an FPGA or an ASIC.

4. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 1, characterized in that: The laser emitter includes at least one 450nm laser and one 1550nm laser.

5. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 1, characterized in that: The laser transmission device employs a telescope system.

6. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 1, characterized in that: The field-of-view acquisition device includes a wide field-of-view camera that uses a large field of view to "search" for the other party's beacon light. The wide field-of-view camera adopts a zoom design, which is used to capture the beacon light at a large divergence angle and to track the beacon light at a small divergence angle.

7. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 1, characterized in that: The adaptive switching communication wavelength cross-medium laser communication device also includes an error compensation system, which includes: The inertial measurement unit senses the attitude changes of its own platform, connects to the APT controller, and transmits the platform attitude change information to the APT controller. The error detection device is connected to the laser transmission device and the APT controller. By detecting the energy distribution of the laser spot on the photosensitive surface of the laser transmission device, it generates an extremely high-precision angle error signal and feeds back the deviation between the center of the spot and the theoretical center to the APT controller in real time. The beam adjustment element is connected to the free space channel, the laser transmission device, and the APT controller. According to the instructions of the APT controller, it can quickly and slightly adjust the emission angle of the laser beam of the laser transmission device in two dimensions through the free space channel, and track the emission angle of the laser beam of the laser transmission device in real time. The APT controller communicates bidirectionally with the main controller, receives error signals from the detector and sensors, runs the control algorithm, calculates the required correction amount, and drives the beam adjustment element to perform compensation.

8. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 7, characterized in that: The error detection device uses a four-quadrant detector.

9. The cross-medium laser communication device with adaptive switching communication wavelength as described in claim 8, characterized in that: The beam adjustment element employs a high-bandwidth, small-angle beam deflection device driven by piezoelectric ceramics or a voice coil motor.

10. A cross-medium laser communication method with adaptive switching of communication wavelength, characterized in that: The adaptive switching communication wavelength cross-medium laser communication device according to any one of claims 1-9 is used to realize adaptive switching communication wavelength cross-medium laser communication, and the method is as follows: Upon receiving a communication request, the main controller parses the command and, based on the communication target and environment, selects and switches to the corresponding channel to issue a link establishment command. In the initial stage of link establishment, the field-of-view acquisition device searches for the beacon light of the other party's terminal to achieve initial discovery and alignment, bringing the other party's terminal into the field of view. After the link establishment is completed and stable tracking is achieved, the communication link maintenance stage begins. Both parties encode and modulate the communication service data, perform electro-optical conversion, and then select different wavelengths of laser as carriers for mutual transmission according to different media. When the laser beam loaded with information is transmitted to the receiver through free space, the receiver performs photoelectric conversion and decoding to recover the original service data information, completing the information exchange.

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