CN112583482B - Novel atmosphere laser communication equipment and communication method - Google Patents
Novel atmosphere laser communication equipment and communication method Download PDFInfo
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- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
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Abstract
The invention discloses novel atmospheric laser communication equipment which comprises a signal encoder, a laser generation module, a carrier selection module, a signal modulation module, a signal receiving module and a signal decoder. The signal encoder converts the information to be sent into an electric signal and sends the electric signal to the signal modulation module; the laser generation module outputs two paths of lasers with different wavelengths in the wave bands of 1600 nanometers to 1700 nanometers as carrier signals; the carrier selection module selects laser with one wavelength, the laser is sent to the signal modulation module to carry out spatial mode modulation on the laser, and the modulated laser is sent to the signal receiving module through the atmosphere; the signal receiving module receives the optical signal and converts the optical signal into an electric signal, and the signal decoder decodes the electric signal by using a neural network to complete atmospheric laser communication. The invention not only comprises intensity modulation, but also modulates the laser space mode, realizes the parallel transmission of multidimensional information, and provides a new solution for improving the communication rate of atmospheric laser communication.
Description
Technical Field
The invention belongs to the technical field of atmospheric laser communication, and particularly relates to novel atmospheric laser communication equipment and a communication method thereof.
Background
The principle of laser communication is similar to that of ordinary radio communication. Except that radio communication transmits sound, video or other signals modulated onto a radio carrier, while laser communication transmits sound, video or other information modulated onto a laser carrier. Laser communication can be divided into terrestrial atmospheric communication, cosmic space communication, and optical fiber communication.
Compared with the traditional communication mode, the laser communication has the outstanding advantages of strong confidentiality and strong anti-interference capability. Compared with optical fiber communication, the atmospheric laser communication does not need optical fiber laying and maintenance; compared with microwave communication, the method does not need examination and approval of frequency use licenses, is not interfered by radio, and cannot meet the increasing communication requirements due to insufficient microwave frequency band resources, limited communication capacity, poor transmission directivity and the like in the conventional microwave communication technology.
The space laser communication technology is rapidly developed in recent years, and a plurality of technical problems are gradually overcome. For example, fast high-precision pointing, capturing, tracking (PAT) technology, atmospheric turbulence effect suppression and compensation technology, narrow-linewidth high-power laser emission technology, low-noise optical amplification technology, high-sensitivity optical reception technology, and the like. The overcoming of the technical problems lays a foundation for realizing the interplanetary laser communication. In recent years, rapid development of space laser communication mainly characterizes in terms of speed, and how to continuously improve communication speed of space laser communication is an urgent task.
For the characteristics of optical signals in space optical communication, intensity modulation/direct detection (IM/DD) is widely used for information transmission. It mainly includes on-off keying modulation (OOK) and single pulse position modulation (L-PPM), Digital Pulse Interval Modulation (DPIM), Double Amplitude Pulse Interval Modulation (DAPIM) and Double Amplitude Pulse Position Modulation (DAPPM) belonging to pulse position modulation PPM. The single laser space communication rate reaches a certain upper limit because of being influenced by a modulation mode, and multiple lasers are adopted for space communication so as to improve the communication rate.
The method researches the space laser communication, provides a practical and effective space laser communication mode, has great value in the fields of national defense and commerce, and is beneficial to the steady development of the boosting laser technology.
Disclosure of Invention
Aiming at the problems, the invention provides novel atmospheric laser communication equipment which simultaneously modulates the intensity and the space mode of laser to realize the parallel transmission of multidimensional information and provides a new solution for improving the communication rate of atmospheric laser communication.
In order to achieve the purpose of the invention, the invention provides novel atmospheric laser communication equipment which is characterized by comprising a signal encoder, a laser generation module, a carrier selection module, a signal modulation module, a signal receiving module and a signal decoder;
the signal encoder is used for converting the information to be sent into a corresponding electric signal and sending the electric signal to the signal modulation module; the laser generation module outputs two paths of lasers with different wavelengths in the wave bands of 1600 nanometers to 1700 nanometers as carrier signals; the carrier selection module selects two paths of carrier signals with different wavelengths generated by the laser generation module, then the carrier signals are sent to the signal modulation module to perform spatial mode modulation on the laser, and the modulated laser is sent to the signal receiving module through the atmosphere; the signal receiving module converts the corresponding optical signals into electric signals, and the electric signals are sent to a signal decoder; the signal decoder decodes the electric signal through a neural network technology to complete atmospheric laser communication.
The laser generation module comprises a semiconductor laser, a wavelength division multiplexer, a first gain optical fiber, a nonlinear optical fiber device, a second gain optical fiber, an optical fiber splitter, a first collimator and a second collimator; the laser device comprises a semiconductor laser, a wavelength division multiplexer, a first gain optical fiber, a nonlinear optical fiber device, a second gain optical fiber, a second collimator and a third collimator, wherein the semiconductor laser emits 980nm laser, the laser is coupled into a cavity through the wavelength division multiplexer, the first gain optical fiber gains the laser, the Raman effect is generated through the nonlinear optical fiber device, the laser with 1620nm wavelength is generated, the laser is divided into two paths of laser with the same intensity through the optical fiber splitter, one path of laser passes through the second gain optical fiber, the laser with 1700nm wavelength is generated, and enters a free space through the first collimator, and the other path of laser with 1620nm wavelength enters the free space through the second collimator.
The first gain optical fiber is Er3+The doped gain fiber and the second gain fiber are Tm3+A gain fiber.
The carrier selection module comprises a stepping motor, a first reflector, a second reflector, a third reflector and a fourth reflector, the first reflector and the third reflector are respectively arranged at the output ends of two paths of laser with different wavelengths, the second reflector and the third reflector are arranged in parallel up and down, and the fourth reflector is arranged at the input end of the signal modulation module and is controlled by the stepping motor to carry out position adjustment.
The signal modulation module comprises a spatial light modulator, the spatial light modulator comprises a plurality of independent units which are arranged in a one-dimensional or two-dimensional array in space, each unit can independently receive the control of optical signals or electric signals and change the optical property of the unit according to the signals, and the spatial mode modulation of the light waves illuminated on the unit is realized.
The signal receiving module comprises a filter and a charge-coupled device image sensor, the filter filters an optical signal and sends the optical signal to the charge-coupled device image sensor after filtering, and the charge-coupled device image sensor detects a spatial mode of receiving the optical signal in real time and converts the corresponding optical signal into an electric signal to send the electric signal to a signal decoder.
The signal decoding module comprises a pre-trained neural network, the pre-trained neural network consists of an output layer, 4 hidden layers and an output layer, the input parameter of the pre-trained neural network is a space mode for receiving laser, and the output parameter is signal coding.
The specific working method is as follows,
(1) a semiconductor laser 1 emits a 980nm laser light source, the laser light source is coupled into a cavity through a wavelength division multiplexer 2, a gain optical fiber 3 gains the laser light, a Raman effect is generated through a nonlinear optical fiber device 4, and laser light with 1620nm wavelength is generated;
(2) the 1620nm laser is divided into two paths of lasers with the same intensity through an optical fiber splitter 5, wherein one path of laser passes through a second gain optical fiber 6 to generate 1700nm laser, and the 1700nm laser enters a free space through a first collimator 7, and the other path of laser with the 1620nm wavelength enters the free space through a second collimator 8;
(3) if the 1620-wavelength laser is selected as the carrier signal, the stepping motor 15 adjusts the fourth reflector 12 to make the 1700 nm-wavelength laser deviate from the 1620-wavelength laser optical path, and the 1620-wavelength laser is transmitted to the spatial light modulator 13 through the third reflector 11 and the second reflector 10 in sequence;
(4) if the 1700nm wavelength laser is selected as a signal carrier, the stepping motor 15 adjusts the fourth reflector 12, the 1620nm wavelength laser is incident to one side of the fourth reflector 12, is reflected by the fourth reflector 12, is emitted out at 90 degrees with the incident direction, deviates from the 1700nm wavelength laser light path, and the 1700nm wavelength laser is transmitted to the spatial light modulator 13 through the first reflector 9 and the fourth reflector 12 in sequence;
(5) the information to be transmitted is firstly converted into 8-bit binary code through the signal encoder 14, the binary code signal is compiled into a corresponding control signal of the spatial light modulator 13 by the signal encoder 14 and is transmitted to the spatial light modulator 13 for spatial mode modulation;
(6) the modulated laser is sent to a filter 16 through a free space to carry out signal filtering, and the laser of other wave bands is filtered out, so that the interference of optical noise is avoided;
(7) the filtered optical signal is sent to a charge coupled device image sensor 17 for detection, the charge coupled device image sensor 17 converts the optical signal into a corresponding electrical signal, and the corresponding electrical signal is sent to a signal decoder 18 for decoding;
(8) the signal decoder 18 processes the input signal through a pre-trained neural network;
(9) after the signal is decoded, the signal is compiled into a character signal according to binary information, and space laser communication is completed.
The laser spatial mode corresponding coding method of the spatial light modulator comprises the following steps: the highest position is a sign position, energy higher than a k value is defined as 1 through energy modulation of laser, energy lower than the k value is defined as 0, the No. 0 to No. 6 positions are determined by space mode distribution of corresponding laser, light spots are divided into 7 parts according to the clockwise direction, the No. 0 position is corresponding to 12 o' clock, the No. 1, 2, 3, 4, 5 and 6 positions are sequentially arranged clockwise, energy distribution is 1, and the No. 0 position is not.
The 1550 nm-1750 nm waveband is located in an atmospheric window area, has good atmospheric penetrability, and is one of ideal wavebands for atmospheric laser communication. 1550nm is one of mainstream wave bands currently used for laser communication, laser in a wave band of 1600-1700nm is used for atmosphere communication, and the wave band has good atmosphere penetrability, meanwhile, signal encryption is realized, and the phenomenon that a signal is stolen in the transmission process is avoided.
A980 nm semiconductor laser is used as a pumping source, pumping laser is coupled into a cavity through a wavelength division multiplexer, and the erbium-doped fiber is a highly-doped fiber (Liekki80-125) with the length of 1m and the dispersion value of 32000fs2And/m, the output coupler outputs 70% of energy of pulses in the cavity to the outside of the cavity, and the large output coupling ratio is favorable for increasing the pulse output energy and outputting laser with the wavelength of 1550 nm. The nonlinear device enables a Raman effect to be generated in the cavity, and laser of a 1550nm waveband is expanded to a 1600nm waveband.
The laser with 1600nm wave band is divided into two paths of laser through a branching unit, one path of laser with 1620nm wave band pumps thulium-doped optical fiber with the length of 30-50cm by adopting a fiber core pumping mode to generate laser with 1700nm wave band, and the laser with 1700nm wave band passes through a collimator and can be used for atmospheric laser communication. The other path of laser with 1620nm wave band passes through a collimator and can be used for atmospheric laser communication.
According to the setting information, the reflector is adjusted by controlling the stepping motor, and one of lasers in a 1600nm wave band to 1700nm wave band can be selected as a carrier signal.
The output laser passes through a spatial light modulator, and the spatial light modulator can perform spatial mode shaping on the laser according to an input signal. And the information to be transmitted is transmitted to a signal encoder, the signal encoder encodes and converts the corresponding signal into a corresponding control signal, and the control signal is transmitted to the spatial light modulator. The spatial light modulator sequentially performs spatial mode shaping on the laser according to the received control signal.
Spatial light modulators comprise a plurality of individual cells spatially arranged in a one-or two-dimensional array, each cell being independently controllable to receive an optical or electrical signal and to change its optical properties in response to the signal, thereby modulating the light waves illuminated thereon. Such devices may change the amplitude or intensity, phase, polarization, and wavelength of a spatially distributed light distribution or convert incoherent light into coherent light under the control of a time-varying electrical or other signal. Due to the property, the optical fiber can be used as a construction unit or a key device in systems such as real-time optical information processing, optical computation, optical neural networks and the like.
The signal receiving module comprises a filter, which screens out useless and interference signals, only receives transmitting laser with the wave band of 1600-1700nm, uses a charge-coupled device image sensor (CCD) to receive corresponding optical signals, converts the received optical signals into electric signals, and sends the electric signals to a signal decoder. The signal decoder uses a trained neural network to process the electric signal, the electric signal is used as an input signal of the neural network, and the neural network outputs a corresponding signal code to restore the signal code into the sending information.
1000 sets of training data are trained in advance by using a neural network, the training data consists of test data and labels, the test data is an output electric signal of a charge-coupled device image sensor (CCD), and the corresponding labels are signal codes.
Compared with the prior art, the invention has the following beneficial effects:
1. the communication wavelength is expanded, the existing atmospheric laser communication technology mostly adopts 980nm or 1550nm wave band laser, and the method
The communication is carried out by using lasers with 1620-1700 nm wave bands, and the communication wavelength is expanded by using the laser different from the lasers used for the existing atmospheric communication. The encryption of information is realized on the signal carrier wave, and the information leakage in the information transmission process is fundamentally avoided.
2. The multi-dimensional information is transmitted in parallel, the laser has a complex and changeable space mode, and the space mode of the laser is modulated in the atmosphere laser communication, so that the method is effectively different from the existing intensity modulation mode. By encoding in laser spatial mode, simultaneous delivery of large amounts of information can be achieved.
3. The signal is decoded at a high speed, the space mode of the laser can realize large information capacity, the signal is encoded through different space modes, the complexity of the space modes holds multiple information and determines the difficulty of signal decoding, and the trained neural network framework is used for identifying the space modes, so that stable, high-speed and reliable signal decoding is realized.
Drawings
FIG. 1 is a schematic diagram of communications of a novel atmospheric laser communication device using 1620nm wavelength laser according to an embodiment;
FIG. 2 is a schematic diagram of an embodiment of a novel atmospheric laser communication device for communication using 1700nm laser;
FIG. 3 is a schematic illustration of a 1620nm wavelength laser spectral signal of a laser communication device of an embodiment;
FIG. 4 is a schematic illustration of a 1620nm wavelength laser spectral signal of a laser communication device of an embodiment;
FIG. 5 is a schematic illustration of laser spatial mode correspondence encoding of a communication protocol of an embodiment;
FIG. 6 is a schematic diagram of a neural network used for decoding of an embodiment;
FIG. 7 is a diagram illustrating an embodiment of a signal receiving module receiving a signal and decoding information;
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the present application and do not limit the present application.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the relevant embodiments, nor are separate alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description thereof.
As shown in fig. 1, 1 denotes a semiconductor laser, 2 denotes a wavelength division multiplexer, 3 denotes a first gain fiber, 4 denotes a nonlinear device, 5 denotes a fiber splitter, 6 denotes a second gain fiber, 7 denotes a first collimator, 8 denotes a second collimator, 9 denotes a first mirror, 10 denotes a second mirror, 11 denotes a third mirror, 12 denotes a fourth mirror, 13 denotes a spatial light modulator, 14 denotes a signal encoder, 15 denotes a stepping motor, 16 denotes a filter, 17 denotes a charge-coupled device image sensor, and 18 denotes a signal decoder.
The laser comprises a semiconductor laser 1, a wave band of which is 980nm, and the maximum output laser power of which is 30w is adjustable;
a first gain fiber 3, an erbium-doped fiber, 1 m;
a nonlinear device 4, optical fiber microspheres with the diameter of 400 microns;
the second gain optical fiber 6 is a thulium-doped optical fiber 50 cm;
a first collimator 7 with a working wavelength of 1050-1700 nm;
a second collimator 8 with a working wavelength of 1050-1700 nm;
a first reflector 9, a gold mirror, single-sided gold plating;
a second reflector 10, a gold mirror, single-sided gold plating;
a third reflector 11, a gold mirror, single-sided gold plating;
a fourth reflector 12, a gold mirror, gold plated on both sides;
the spatial light modulator 13 has an operating wavelength of 1600-1700nm, a filling factor of more than 90% and a resolution of 1920 x 1200;
the signal encoder 14 is a notebook computer, and the CPU is an AMD Ryzen 74800H, 16G running memory;
the stepping motor 15 can adjust the measuring range to be 0-2 cm;
a filter 16, a free space isolator, a working wavelength of 1600-;
the signal decoder 18, the notebook computer, CPU for AMD Ryzen 74800H, 16G run memory;
the novel atmospheric laser communication device shown in fig. 1 comprises a laser generation module, a carrier selection module, a signal encoder 14, a signal modulation module, a signal receiving module and a signal decoder 18; the signal encoder 14 is configured to convert information to be transmitted into a corresponding electrical signal, and transmit the electrical signal to the signal modulation module; the laser generation module outputs two paths of lasers with different wavelengths in the wave bands of 1600 nanometers to 1700 nanometers as carrier signals; the carrier selection module selects two paths of carrier signals with different wavelengths generated by the laser generation module, then the carrier signals are sent to the signal modulation module to perform spatial mode modulation on the laser, and the modulated laser is sent to the signal receiving module through the atmosphere; the signal receiving module converts the corresponding optical signal into an electrical signal, and the electrical signal is sent to the signal decoder 18; the signal decoder 18 decodes the electrical signal through a neural network technology to complete the atmospheric laser communication.
The laser generation module comprises a semiconductor laser 1, a wavelength division multiplexer 2, a first gain optical fiber 3, a nonlinear optical fiber device 4, a second gain optical fiber 6, an optical fiber splitter 5, a first collimator 7 and a second collimator 8; the semiconductor laser 1 emits 980nm laser, the laser is coupled into a cavity through a wavelength division multiplexer 2, a first gain optical fiber 3 gains the laser, a Raman effect is generated through a nonlinear optical fiber device 4, laser with 1620nm wavelength is generated, the laser is divided into two paths of laser with the same intensity through an optical fiber branching device 5, one path of the laser passes through a second gain optical fiber 6, laser with 1700nm wavelength is generated, the laser enters a free space through a first collimator 7, and the laser with 1620nm wavelength enters the free space through a second collimator 8. Wherein the first gain fiber is Er3+The doped gain fiber and the second gain fiber are doped with Tm3+A gain fiber. The carrier selection module comprises a stepping motor 15, a first reflector 9, a second reflector 10, a third reflector 11 and a fourth reflector 12, wherein the first reflector 9 and the third reflector 11 are respectively arranged at the output ends of two paths of laser with different wavelengths, and the second reflectorThe mirror 10 and the third reflector 11 are arranged in parallel up and down, and the fourth reflector 12 is arranged at the input end of the signal modulation module and is controlled by a stepping motor 15 to adjust the position.
The signal modulation module in this embodiment includes a spatial light modulator 13, which performs spatial modulation on the emitted laser according to an electrical modulation signal generated by a signal encoder; the spatial light modulator 13 comprises a plurality of individual cells spatially arranged in a one-dimensional or two-dimensional array, each cell being capable of independently receiving control of an optical or electrical signal and changing its optical properties in response to the control signal to effect modulation of light waves illuminated thereon. Such devices may change the amplitude or intensity, phase, polarization, and wavelength of a spatially distributed light distribution or convert incoherent light into coherent light under the control of a time-varying electrical or other signal. Due to the property, the optical fiber can be used as a construction unit or a key device in systems such as real-time optical information processing, optical computation, optical neural networks and the like. Laser output by the laser generation module passes through the spatial light modulator 13, and the spatial light modulator 13 can perform spatial mode shaping on the laser according to an input signal; the information to be transmitted is sent to the signal encoder 14, the signal encoder 14 encodes and converts the corresponding signal into a corresponding control signal, the control signal is sent to the spatial light modulator 13, and the spatial light modulator 13 sequentially performs spatial mode shaping on the laser according to the received control signal.
The signal receiving module described in this embodiment includes a filter 16 and a ccd image sensor 17, the filter 16 filters an optical signal, and sends the filtered optical signal to the ccd image sensor 17, and the ccd image sensor 17 detects a spatial mode of receiving light in real time, and converts a corresponding optical signal into an electrical signal to send to the signal decoder 18. The signal receiving module receives only the transmitting laser light in the 1600-1700nm band, receives a corresponding optical signal by using a charge-coupled device image sensor (CCD)17, converts the received optical signal into an electrical signal, and transmits the electrical signal to the signal decoder 18.
The signal decoding module in this embodiment includes a pre-trained neural network, the pre-trained neural network is composed of an output layer, 4 hidden layers, and an output layer, an input parameter of the pre-trained neural network is a spatial mode for receiving laser, and an output parameter is a signal code. The signal decoder 18 processes the electrical signal using a pre-trained neural network, the electrical signal serves as an input signal to the neural network, and the neural network outputs a corresponding signal code to restore the transmission information. 1000 sets of training data are trained in advance by using a neural network, the training data consists of test data and labels, the test data is an output electric signal of a charge-coupled device image sensor (CCD)17, and the corresponding labels are signal codes.
In the embodiment, a semiconductor laser 1 emits a 980nm laser light source, the laser light source is coupled into a cavity through a wavelength division multiplexer 2, a gain optical fiber 3 gains the laser light, a Raman effect is generated through a nonlinear optical fiber device 4, and laser light with 1620nm wavelength is generated; the 1620nm laser is divided into two paths of lasers with the same intensity through an optical fiber splitter 5, wherein one path of laser passes through a second gain optical fiber 6 to generate 1700nm laser, and the 1700nm laser enters a free space through a first collimator 7, and the other path of laser with the 1620nm wavelength enters the free space through a second collimator 8;
if the 1620-wavelength laser is selected as the carrier signal, the stepping motor 15 adjusts the fourth mirror 12 to make the 1700 nm-wavelength laser deviate from the 1620-wavelength laser optical path, and the 1620-wavelength laser is transmitted to the spatial light modulator 13 through the third mirror 11 and the second mirror 10 in sequence, as shown in fig. 1;
if the 1700nm wavelength laser is selected as a signal carrier, the stepping motor 15 adjusts the fourth reflector 12, the 1620nm wavelength laser is incident to one side of the fourth reflector 12, is reflected by the fourth reflector 12, and is emitted out at 90 degrees with the incident direction, deviating from the 1700nm wavelength laser light path, and the 1700nm wavelength laser is transmitted to the spatial light modulator 13 through the first reflector 9 and the fourth reflector 12 in sequence, as shown in fig. 2;
the information to be transmitted is firstly converted into 8-bit binary code through the signal encoder 14, the binary code signal is compiled into a corresponding control signal of the spatial light modulator 13 by the signal encoder 14 and is transmitted to the spatial light modulator 13 for spatial mode modulation; the modulated laser is sent to a filter 16 through a free space to carry out signal filtering, and the laser of other wave bands is filtered out, so that the interference of optical noise is avoided; the filtered optical signal is sent to a charge coupled device image sensor 17 for detection, the charge coupled device image sensor 17 converts the optical signal into a corresponding electrical signal, and the corresponding electrical signal is sent to a signal decoder 18 for decoding; the signal decoder 18 processes the input signal through a pre-trained neural network; after the signal is decoded, the signal is compiled into a character signal according to binary information, and space laser communication is completed.
In one embodiment, the novel atmospheric laser communication device is used for information communication, and the spatial light modulation method is used for sending the Hello World, receiving signals at a receiving end, decoding is realized, and the Hello Word is received. A communication system is shown in fig. 1. In fig. 1, 1 denotes a light source, 2 denotes a wavelength division multiplexer, 3 denotes a first gain fiber, 4 denotes a nonlinear device, 5 denotes a fiber splitter, 6 denotes a second gain fiber, 7 denotes a first collimator, 8 denotes a second collimator, 9 denotes a first mirror, 10 denotes a second mirror, 11 denotes a third mirror, 12 denotes a fourth mirror, 13 denotes a spatial light modulator, 14 denotes a signal encoder, 15 denotes a stepping motor, 16 denotes a filter, 17 denotes a charge-coupled device image sensor, and 18 denotes a signal decoder.
The laser comprises a semiconductor laser 1, a wave band of which is 980nm, and the maximum output laser power of which is 30w is adjustable;
a first gain fiber 3, an erbium-doped fiber, 1 m;
a nonlinear device 4, optical fiber microspheres with the diameter of 400 microns;
a second gain fiber 6, a thulium-doped fiber, 50 cm;
a first collimator 7 with a working wavelength of 1050-1700 nm;
a second collimator 8 with a working wavelength of 1050-1700 nm;
a first reflector 9, a gold mirror, single-sided gold plating;
a second reflector 10, a gold mirror, single-sided gold plating;
a third reflector 11, a gold mirror, single-sided gold plating;
a fourth reflector 12, a gold mirror, gold plated on both sides;
the spatial light modulator 13 has an operating wavelength of 1600-1700nm, a filling factor of more than 90% and a resolution of 1920 x 1200;
the signal encoder 14 is a notebook computer, and the CPU is an AMD Ryzen 74800H, 16G running memory;
the stepping motor 15 can adjust the measuring range to be 0-2 cm;
a filter 16, a free space isolator, a working wavelength of 1600-1700nm, a maximum light beam diameter of 4.7mm and a maximum power of 15W;
the signal decoder 18, the notebook computer, CPU for AMD Ryzen 74800H, 16G run memory;
the communication method for selecting the 1620nm wavelength laser as the signal carrier wave is as follows:
(1) a semiconductor laser 1 emits a 980nm laser light source, the laser light source is coupled into a cavity through a wavelength division multiplexer 2, a gain optical fiber 3 gains the laser light, a Raman effect is generated through a nonlinear optical fiber device 4, and laser light with 1620nm wavelength is generated;
(2) the 1620nm laser is divided into two paths of lasers with the same intensity through an optical fiber splitter 5, wherein one path of laser passes through a second gain optical fiber 6 to generate 1700nm laser, and the 1700nm laser enters a free space through a first collimator 7, and the other path of laser with the 1620nm wavelength enters the free space through a second collimator 8;
(3) the stepping motor 15 adjusts the fourth reflector 12 to make 1700nm wavelength laser deviate from 1620nm wavelength laser light path, the 1620nm wavelength laser is transmitted to the spatial light modulator 13 through the third reflector 11 and the second reflector 10 in sequence, and the output laser spectrum is as shown in fig. 3;
(4) the information to be transmitted is converted into 8-bit binary code by a signal encoder 14; the information "Hello World" to be transmitted is converted into binary code by the signal encoder 14, which is "01001000B 01100101B 01101100B 01101100B 01101111B 00100000B 01010111B 01101111B 01110010B 01101100B 01100100B 00100001B 00000000B", referring to the code map, as shown in fig. 5. The novel atmospheric laser communication equipment provided by the invention can realize the transmission of 8bit information at a single time, 8-bit coded information is sent at a single time, the highest bit is a sign bit, the modulation is carried out by the energy of laser, the energy is higher than a k value and is defined as 1, the energy is lower than the k value and is defined as 0, the number 0 to 6 is determined by the space mode distribution of corresponding laser, a light spot is divided into 7 parts according to the clockwise direction, the number 0 position is corresponding to 12 o' clock, the number 1, 2, 3, 4, 5, 6 and 7 positions are clockwise in sequence, the energy distribution is 1, and the number 0 is not, as shown in figure 5;
(5) the signal encoder 14 compiles the corresponding signal into a control signal of the spatial light modulator 13 and sends the control signal to the spatial light modulator 13 for spatial mode modulation;
(6) the modulated laser is sent to a filter 16 through a free space to carry out signal filtering, and the laser of other wave bands is filtered out, so that the interference of optical noise is avoided;
(7) the filtered optical signal is sent to a charge coupled device image sensor 17 for detection, the charge coupled device image sensor 17 converts the optical signal into a corresponding electrical signal, and the corresponding electrical signal is sent to a signal decoder 18 for decoding;
(8) the signal decoder 18 processes the input signal through a pre-trained neural network; the schematic diagram of the neural network structure is shown in fig. 6, the neural network is trained in advance according to a large amount of data, and a high-speed and accurate decoding mode is established;
(9) after the signal is decoded, the signal is compiled into a character signal according to binary information, and space laser communication is completed.
The process of receiving and decoding signals by the signal receiving module is shown in fig. 7.
The decoding information is '01001000B 01100101B 01101100B 01101100B 01101111B 00100000B 01010111B 01101111B 01110010B 01101100B 01100100B 00100001B 00000000B', and the decoding information is compiled into a character signal 'Hello World' according to binary information to complete space laser communication.
EXAMPLE III
The novel atmosphere laser communication equipment is adopted to carry out information communication, a spatial light modulation mode is used for sending the Hello World, signals are received at a receiving end, decoding is realized, and the Hello Word is received.
The details of the related devices are as follows:
the semiconductor laser 1 generates a light source with the wave band of 980nm, and the maximum output laser power is adjustable by 30 w;
a first gain fiber 3, an erbium-doped fiber, 1 m;
a nonlinear optical fiber device 4, optical fiber microspheres with the diameter of 400 microns;
a second gain fiber 6, a thulium-doped fiber, 50 cm;
a first collimator 7 with a working wavelength of 1050-1700 nm;
a second collimator 8 with a working wavelength of 1050-1700 nm;
a first reflector 9, a gold mirror, single-sided gold plating;
a second reflector 10, a gold mirror, single-sided gold plating;
a third reflector 11, a gold mirror, single-sided gold plating;
a fourth reflector 12, a gold mirror, gold plated on both sides;
the spatial light modulator 13 has an operating wavelength of 1600-1700nm, a filling factor of more than 90% and a resolution of 1920 x 1200;
the signal encoder 14 is a notebook computer, and the CPU is an AMD Ryzen 74800H, 16G running memory;
the stepping motor 15 can adjust the measuring range to be 0-2 cm;
a filter 16, a free space isolator, a working wavelength of 1600-;
the signal decoder 18, the notebook computer, CPU for AMD Ryzen 74800H, 16G run memory;
the communication method for selecting 1700nm wavelength laser as a signal carrier is as follows:
(1) a semiconductor laser 1 emits a 980nm laser light source, the laser light source is coupled into a cavity through a wavelength division multiplexer 2, a gain optical fiber 3 gains the laser light, a Raman effect is generated through a nonlinear optical fiber device 4, and laser light with 1620nm wavelength is generated;
(2) the 1620nm laser is divided into two paths of lasers with the same intensity through an optical fiber splitter 5, wherein one path of laser passes through a second gain optical fiber 6 to generate 1700nm laser, and the 1700nm laser enters a free space through a first collimator 7, and the other path of laser with the 1620nm wavelength enters the free space through a second collimator 8;
(3) the stepping motor 15 adjusts the fourth reflector 12, the 1620nm wavelength laser is incident to one side of the fourth reflector 12, is reflected by the fourth reflector 12, is emitted out at 90 degrees with the incident direction, deviates from the 1700nm wavelength laser light path, the 1700nm wavelength laser is transmitted to the spatial light modulator 13 through the first reflector 9 and the fourth reflector 12 in sequence, and the laser spectrum is as shown in fig. 4;
(4) the information to be transmitted is converted into 8-bit binary code by a signal encoder 14; the information "Hello World" to be transmitted is converted into binary code by the signal encoder 14, which is "01001000B 01100101B 01101100B 01101100B 01101111B 00100000B 01010111B 01101111B 01110010B 01101100B 01100100B 00100001B 00000000B", referring to the code map, as shown in fig. 5. The novel atmospheric laser communication equipment provided by the invention can realize the transmission of 8bit information at a single time, 8-bit coded information is sent at a single time, the highest position is a sign position, the modulation is carried out through the energy of laser, the energy is higher than a k value and is defined as 1, the energy is lower than the k value and is defined as 0, the positions from 0 to 6 are determined by the spatial mode distribution of the corresponding laser, a light spot is divided into 7 parts according to the clockwise direction, the corresponding position of 12 o' clock is the position of 0, the clockwise direction is the positions of 1, 2, 3, 4, 5, 6 and 7, the energy distribution is 1, and the energy distribution is 0 if not;
(5) the signal encoder 14 compiles the corresponding signal into a control signal of the spatial light modulator 13 and sends the control signal to the spatial light modulator 13 for spatial mode modulation;
(6) the modulated laser is sent to a filter 16 through a free space to carry out signal filtering, and the laser of other wave bands is filtered out, so that the interference of optical noise is avoided;
(7) the filtered optical signal is sent to a charge coupled device image sensor 17 for detection, the charge coupled device image sensor 17 converts the optical signal into a corresponding electrical signal, and the corresponding electrical signal is sent to a signal decoder 18 for decoding;
(8) the signal decoder 18 processes the input signal through a pre-trained neural network;
(9) after the signal is decoded, the signal is compiled into a character signal according to binary information, and space laser communication is completed.
It should be noted that the terms "first \ second \ third" referred to in the embodiments of the present application merely distinguish similar objects, and do not represent a specific ordering for the objects, and it should be understood that "first \ second \ third" may exchange a specific order or sequence when allowed. It should be understood that "first \ second \ third" distinct objects may be interchanged under appropriate circumstances such that the embodiments of the application described herein may be implemented in an order other than those illustrated or described herein.
The terms "comprising" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device that comprises a list of steps or modules is not limited to the listed steps or modules but may alternatively include other steps or modules not listed or inherent to such process, method, product, or device.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (8)
1. The novel atmosphere laser communication equipment is characterized by comprising a signal encoder, a laser generation module, a carrier selection module, a signal modulation module, a signal receiving module and a signal decoder;
the signal encoder is used for converting the information to be sent into a corresponding electric signal and sending the electric signal to the signal modulation module; the laser generation module outputs two paths of lasers with different wavelengths in the wave bands of 1600 nanometers to 1700 nanometers as carrier signals; the carrier selection module selects two paths of carrier signals with different wavelengths generated by the laser generation module, then the carrier signals are sent to the signal modulation module to perform spatial mode modulation on the laser, and the modulated laser is sent to the signal receiving module through the atmosphere; the signal receiving module converts the corresponding optical signals into electric signals, and the electric signals are sent to a signal decoder; the signal decoder decodes the electric signal through a neural network technology to complete atmospheric laser communication; the laser generation module comprises a semiconductor laser, a wavelength division multiplexer, a first gain optical fiber, a nonlinear optical fiber device, a second gain optical fiber, an optical fiber splitter, a first collimator and a second collimator; the laser device comprises a semiconductor laser, a wavelength division multiplexer, a first gain optical fiber, a nonlinear optical fiber device, a second gain optical fiber, a second collimator and a third collimator, wherein the semiconductor laser emits 980nm laser, the laser is coupled into a cavity through the wavelength division multiplexer, the first gain optical fiber gains the laser, the Raman effect is generated through the nonlinear optical fiber device, the laser with 1620nm wavelength is generated, the laser is divided into two paths of laser with the same intensity through the optical fiber splitter, one path of laser passes through the second gain optical fiber, the laser with 1700nm wavelength is generated, and enters a free space through the first collimator, and the other path of laser with 1620nm wavelength enters the free space through the second collimator.
2. The novel atmospheric laser communication device of claim 1, wherein the first gain fiber is Er3+The doped gain fiber and the second gain fiber are Tm3+A gain fiber.
3. The novel atmospheric laser communication device according to claim 1, wherein the carrier selection module includes a stepping motor, a first reflector, a second reflector, a third reflector and a fourth reflector, the first reflector and the third reflector are respectively disposed at output ends of two paths of laser with different wavelengths, the second reflector and the third reflector are disposed in parallel up and down, and the fourth reflector is disposed at an input end of the signal modulation module and is controlled by the stepping motor to perform position adjustment.
4. The novel atmospheric laser communication device as claimed in claim 1, wherein the signal modulation module comprises a spatial light modulator, the spatial light modulator comprises a plurality of independent units, the independent units are spatially arranged in a one-dimensional or two-dimensional array, each unit can independently receive control of an optical signal or an electrical signal, and change its optical property according to the control of the optical signal or the electrical signal, so as to realize spatial mode modulation of the light wave illuminated on the unit.
5. The novel atmospheric laser communication device as claimed in claim 1, wherein the signal receiving module includes a filter and a ccd image sensor, the filter filters the optical signal and sends the filtered optical signal to the ccd image sensor, and the ccd image sensor detects the spatial mode of the received light in real time and converts the corresponding optical signal into an electrical signal to send to the signal decoder.
6. The novel atmospheric laser communication device as claimed in claim 1, wherein the signal decoder comprises a pre-trained neural network, the pre-trained neural network is composed of an output layer, 4 hidden layers and an output layer, an input parameter of the pre-trained neural network is a spatial mode of receiving laser, and an output parameter is a signal code.
7. A communication method of novel atmospheric communication laser equipment is characterized by comprising the following specific working methods,
(1) a semiconductor laser 1 emits a 980nm laser light source, the laser light source is coupled into a cavity through a wavelength division multiplexer 2, a gain optical fiber 3 gains the laser light, a Raman effect is generated through a nonlinear optical fiber device 4, and laser light with 1620nm wavelength is generated;
(2) the 1620nm laser is divided into two paths of lasers with the same intensity through an optical fiber splitter 5, wherein one path of laser passes through a second gain optical fiber 6 to generate 1700nm laser, and the 1700nm laser enters a free space through a first collimator 7, and the other path of laser with the 1620nm wavelength enters the free space through a second collimator 8;
(3) if the 1620-wavelength laser is selected as the carrier signal, the stepping motor 15 adjusts the fourth reflector 12 to make the 1700 nm-wavelength laser deviate from the 1620-wavelength laser optical path, and the 1620-wavelength laser is transmitted to the spatial light modulator 13 through the third reflector 11 and the second reflector 10 in sequence;
(4) if the 1700nm wavelength laser is selected as a signal carrier, the stepping motor 15 adjusts the fourth reflector 12, the 1620nm wavelength laser is incident to one side of the fourth reflector 12, is reflected by the fourth reflector 12, is emitted out at 90 degrees with the incident direction, deviates from the 1700nm wavelength laser light path, and the 1700nm wavelength laser is transmitted to the spatial light modulator 13 through the first reflector 9 and the fourth reflector 12 in sequence;
(5) the information to be transmitted is firstly converted into 8-bit binary code through the signal encoder 14, the binary code signal is compiled into a corresponding control signal of the spatial light modulator 13 by the signal encoder 14 and is transmitted to the spatial light modulator 13 for spatial mode modulation;
(6) the modulated laser is sent to a filter 16 through a free space to carry out signal filtering, and the laser of other wave bands is filtered out, so that the interference of optical noise is avoided;
(7) the filtered optical signal is sent to a charge coupled device image sensor 17 for detection, the charge coupled device image sensor 17 converts the optical signal into a corresponding electrical signal, and the corresponding electrical signal is sent to a signal decoder 18 for decoding;
(8) the signal decoder 18 processes the input signal through a pre-trained neural network;
(9) after the signal is decoded, the signal is compiled into a character signal according to binary information, and space laser communication is completed.
8. The communication method of the novel atmospheric communication laser device according to claim 7, wherein the laser spatial mode corresponding coding method of the spatial light modulator is as follows: the highest position is a sign position, energy higher than a k value is defined as 1 through energy modulation of laser, energy lower than the k value is defined as 0, the No. 0 to No. 6 positions are determined by space mode distribution of corresponding laser, light spots are divided into 7 parts according to the clockwise direction, the No. 0 position is corresponding to 12 o' clock, the No. 1, 2, 3, 4, 5 and 6 positions are sequentially arranged clockwise, energy distribution is 1, and the No. 0 position is not.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1450731A (en) * | 2002-04-11 | 2003-10-22 | 阿尔卡塔尔公司 | Generator of optical data carrier signals with selectable carrier wavedengths |
| CN101212115A (en) * | 2006-12-28 | 2008-07-02 | 中国科学院半导体研究所 | Tunable erbium-doped optical fiber annular chamber laser |
| CN103269012A (en) * | 2013-05-31 | 2013-08-28 | 中国科学院上海光学精密机械研究所 | Single-frequency Raman optical fiber laser device system |
| CN108768516A (en) * | 2018-07-02 | 2018-11-06 | 北京卫星信息工程研究所 | The laser space communication terminal of wavelength fast tunable |
| CN108833015A (en) * | 2018-09-06 | 2018-11-16 | 清华-伯克利深圳学院筹备办公室 | A kind of radio optical communication system based on tunable VCSEL |
| CN108964761A (en) * | 2018-07-02 | 2018-12-07 | 北京卫星信息工程研究所 | Highly reliable space optical communication signal modulation terminal and method based on software radio |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6614819B1 (en) * | 1999-09-02 | 2003-09-02 | Agility Communications, Inc. | Method of modulating an optical wavelength with an opto-electronic laser with integrated modulator |
| CN107147002B (en) * | 2017-07-07 | 2019-03-22 | 中国科学院半导体研究所 | Frequency regulator and method when optical maser wavelength based on coupling crosstalk theory is adjustable and long |
-
2020
- 2020-11-17 CN CN202011284108.XA patent/CN112583482B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1450731A (en) * | 2002-04-11 | 2003-10-22 | 阿尔卡塔尔公司 | Generator of optical data carrier signals with selectable carrier wavedengths |
| CN101212115A (en) * | 2006-12-28 | 2008-07-02 | 中国科学院半导体研究所 | Tunable erbium-doped optical fiber annular chamber laser |
| CN103269012A (en) * | 2013-05-31 | 2013-08-28 | 中国科学院上海光学精密机械研究所 | Single-frequency Raman optical fiber laser device system |
| CN108768516A (en) * | 2018-07-02 | 2018-11-06 | 北京卫星信息工程研究所 | The laser space communication terminal of wavelength fast tunable |
| CN108964761A (en) * | 2018-07-02 | 2018-12-07 | 北京卫星信息工程研究所 | Highly reliable space optical communication signal modulation terminal and method based on software radio |
| CN108833015A (en) * | 2018-09-06 | 2018-11-16 | 清华-伯克利深圳学院筹备办公室 | A kind of radio optical communication system based on tunable VCSEL |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102022133962A1 (en) | 2022-12-19 | 2024-06-20 | Friedrich-Schiller-Universität Jena Körperschaft des öffentlichen Rechts | PROCESSING MEASURED RAMAN SPECTRA WITH NEURAL NETWORKS |
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