CN115378505A - Multi-mode optical fiber turbulence-resistant free space optical communication system, device and method - Google Patents
Multi-mode optical fiber turbulence-resistant free space optical communication system, device and method Download PDFInfo
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- CN115378505A CN115378505A CN202211013903.4A CN202211013903A CN115378505A CN 115378505 A CN115378505 A CN 115378505A CN 202211013903 A CN202211013903 A CN 202211013903A CN 115378505 A CN115378505 A CN 115378505A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- 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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- 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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- H—ELECTRICITY
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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 a free space optical communication system, a device and a method for resisting turbulence of multimode optical fiber, relating to the technical field of optical communication and solving the problems that the communication error rate performance of the free space optical communication system is reduced and the interruption probability of a free space optical communication link is increased due to atmospheric turbulence, and the technical scheme is characterized in that: the multimode optical fiber is used for directly receiving the free space light beam after the transmission light beam is distorted due to the atmospheric turbulence, and the free space light beam is converted into Gaussian light beams with a plurality of modes for parallel signal detection, so that the purposes of improving the receiving efficiency of the system, improving the communication stability and reducing the error rate are achieved. Meanwhile, the photoelectric detector is used for detecting the multi-mode parallel signals, so that the purposes of improving the receiving efficiency of the system, improving the communication stability and reducing the error rate are achieved. After the multimode optical fiber receives the optical power, the amplification processing module is used for amplifying the received optical power, so that the purpose of compensating the optical power loss caused by the long-distance free space turbulent flow is achieved.
Description
Technical Field
The invention relates to the technical field of optical communication, in particular to an anti-turbulence free space optical communication system, an anti-turbulence free space optical communication device and an anti-turbulence free space optical communication method for multimode optical fibers.
Background
With the rapid development of the information society, the demand for communication capacity is increasing, and the spectrum resources of traditional Radio Frequency (RF) communication are gradually limited, which is difficult to meet the increasing demand for wireless communication bandwidth.
The free space optical communication system is an optical communication system which takes laser light waves as carrier waves and takes the atmosphere as a transmission medium, and compared with the traditional radio frequency communication, the free space optical communication system has the advantages of high communication capacity, high confidentiality, strong anti-interference capability, no authorization of frequency spectrum, flexible installation and the like.
The laser modes can be divided into a transverse mode and a longitudinal mode, the transverse mode is the optical field distribution of the laser beam on the cross section, the symbols TEMmn represent various transverse modes, m and n are positive integers, and respectively represent the ordinal numbers of points with zero light intensity in the directions of an x axis and a y axis, and the ordinal numbers are called mode ordinal numbers. The light intensity of any point in the light spot is not zero and is called as TEM00 mode; if the light intensity of the light spot is zero at a point in the x direction, the light spot is called as a TEM10 mode; there is a little light intensity zero in the y-direction, called TEM01 mode. By analogy, the larger the mode numbers m and n, the larger the number of points with zero intensity in the spot. The other modes are referred to as higher order modes except that the TEM00 mode is the fundamental mode. In addition, there are other manifestations of higher order modes in free space and fiber, such as Laguerre-Gaussian (LG), hermite-Gaussian (HG), polarization (LP), orbital Angular Momentum (OAM), fiber Eigenmodes (Eigenmodes), etc.
In free-space optical links, random fluctuations in the refractive index of air caused by time-varying atmospheric turbulence disrupt the lateral amplitude and phase distribution of a propagating fundamental mode gaussian beam, resulting in mode coupling of the fundamental mode gaussian beam into a higher order mode beam, a phenomenon also known as mode spreading. The mode expansion effect caused by the atmospheric turbulence can directly reduce the coupling efficiency from free space distorted light beams to single-mode optical fibers in the traditional free space optical communication system, so that larger power loss and power fluctuation are caused, the communication error rate performance of the free space optical communication system is further reduced, and the interruption probability of a free space optical communication link is increased.
Disclosure of Invention
The invention aims to provide an anti-turbulence free space optical communication system, an anti-turbulence free space optical communication device and an anti-turbulence free space optical communication method for multimode optical fibers.
The technical purpose of the invention is realized by the following technical scheme:
a multimode optical fiber turbulence-resistant free-space optical communication system, comprising: a multimode optical fiber for receiving the spatially turbulent atmospheric light beam; the output end of the coupling module is connected with the input end of the multimode optical fiber and is used for coupling the space beam subjected to the atmospheric turbulence into the multimode optical fiber; the input end of the multimode demultiplexing module is connected with the output end of the multimode optical fiber and is used for separating the spatial light beam received by the multimode optical fiber into a plurality of Gaussian light beams; and the input end of the photoelectric detector is connected with the output end of the multimode demultiplexing module and is used for detecting parallel signals of the Gaussian beams.
Further, the device also comprises an amplification processing module; the input end of the amplification processing module is connected with the output end of the multimode optical fiber; the output end of the amplification processing module is connected with the input end of the multimode demultiplexing module; for amplifying the spatial light beam received by the multimode optical fiber.
Furthermore, the multimode optical fiber comprises N optical fiber modes, wherein N is more than or equal to 3 and is an integer.
Furthermore, the multi-mode demultiplexing module comprises M output ports, wherein M is more than or equal to 3 and less than or equal to N, and M is an integer.
Further, the photodetector includes a direct optical detector and a coherent optical detector.
An anti-turbulence free-space optical communication device of a multimode optical fiber, comprising the anti-turbulence free-space optical communication system of the multimode optical fiber, and further comprising: a laser for emitting a laser beam; the input end of the modulation module is connected with the output end of the laser and is used for modulating the laser beam into a laser signal; and the input end of the conversion module is connected with the output end of the intensity modulator and is used for converting the laser signal into a space beam.
The device further comprises a spatial light modulator, wherein the input end of the spatial light modulator is connected with the output end of the conversion module and is used for enabling the first Gaussian beam to pass through the atmosphere turbulence; and the output end of the spatial light modulator is connected with the input end of the coupling module.
Further, the modulation module comprises an intensity modulator and a waveform generator; and the input end of the intensity modulator is respectively connected with the output ends of the laser and the waveform generator.
Further, the conversion module comprises a polarization controller and an optical fiber collimator which are connected in sequence; and the input end of the polarization controller is connected with the output end of the intensity modulator.
A communication method of a free space optical communication system based on the anti-turbulence multimode optical fiber comprises the following steps: coupling the atmospheric turbulent spatial light beam into a multimode optical fiber; separating a spatial beam received in a multimode fiber into a plurality of Gaussian beams; and carrying out parallel signal detection on the Gaussian beams.
Compared with the prior art, the invention has the following beneficial effects:
(1) the multimode optical fiber is used for directly receiving the free space light beam after the transmission light beam is distorted due to the atmospheric turbulence, and the free space light beam is converted into Gaussian light beams with a plurality of modes for parallel signal detection, so that the purposes of improving the receiving efficiency of the system, improving the communication stability and reducing the error rate are achieved.
(2) And a feedback system using an additional wave front sensing and phase correcting device is not needed, so that the complexity of the system is greatly reduced.
(3) And the multimode optical fiber is used for receiving, so that the volume of a receiving system is greatly reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic diagram of an anti-turbulence free-space optical communication system with multimode optical fibers according to one embodiment;
FIG. 2 is a schematic diagram of an amplifier of an anti-turbulence free-space optical communication system with multimode optical fibers according to an embodiment;
FIG. 3 is a schematic diagram of an embodiment of a multimode fiber turbulence free-space optical communication device;
fig. 4 is a comparison graph of the received optical power distribution of the conventional single-mode optical fiber and the multimode optical fiber in this embodiment at different turbulence intensities measured by a free space optical communication apparatus for preventing turbulence using a multimode optical fiber in this embodiment, wherein (a) represents a received optical power fluctuation graph when the turbulence intensity is D/r0= 8; (b) Represents a received light power fluctuation graph when the turbulence intensity is D/r0= 16;
FIG. 5 is a graph comparing the launch optical power and the bit error rate curve of a conventional single mode fiber and the multimode fiber of the present embodiment, measured in the free space optical communication device using a multimode fiber for turbulence resistance, wherein (a) shows the launch optical power and the bit error rate curve when the turbulence intensity is D/r0= 8; (b) The graph shows the emitted light power and the error rate when the turbulence intensity is D/r0= 16.
Reference numbers and corresponding part names in the drawings:
1-a laser; 2-an intensity modulator; 3-a waveform generator; 4-a fiber amplifier; 5-a variable optical attenuator; 6-a polarization controller; 7-a fiber collimator; 8-a spatial light modulator; 9-a mirror;
100-a coupling module; 200-multimode optical fiber; 300-a multimode demultiplexing module; 400-a photodetector; 500-amplifying processing module.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and the accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not used as limiting the present invention.
Example (b): as shown in fig. 1-5, a multimode fiber turbulence-resistant free-space optical communication system, apparatus and method,
a multimode optical fiber turbulence-resistant free-space optical communication system, as shown in fig. 1, comprising: a multimode optical fiber 200, said multimode optical fiber 200 for receiving an atmospheric turbulent spatial light beam; a coupling module 100, an output end of the coupling module 100 being connected with an input end of the multimode fiber 200, for coupling the spatial light beam subjected to the atmospheric turbulence into the multimode fiber 200; the multimode demultiplexing module 300, an input end of the multimode demultiplexing module 300 is connected with an output end of the multimode optical fiber 200, and is used for separating the spatial light beam received by the multimode optical fiber 200 into a plurality of gaussian light beams; and an input end of the photodetector 400 is connected with an output end of the multimode demultiplexing module 300, and is used for performing parallel signal detection on the gaussian beam. The multimode optical fiber 200 comprises N optical fiber modes, wherein N is more than or equal to 3, and N is an integer. The multi-mode demultiplexing module 300 comprises M output ports, wherein M is greater than or equal to 3 and less than or equal to N, and M is an integer. The photodetector 400 includes a direct optical detector and a coherent optical detector. The method specifically comprises the following steps:
the beam coupling module 100, the multimode optical fiber 200, the multimode demultiplexing module 300 and the photodetector 400 are connected in sequence. The light beam coupling module 100 may be formed by one or more lens groups, the light beam coupling module 100 is matched with a subsequent multimode optical fiber 200, and converges and couples a spatial light beam transmitted by an atmospheric turbulence into the multimode optical fiber 200, the multimode optical fiber 200 supports transmission of N optical fiber modes, N is greater than or equal to 3, the supported modes include high-order mode light beams such as Linear polarization mode (LP), orbital Angular Momentum mode (OAM), and optical fiber eigenmode (Eigenmodes), the multimode demultiplexing module 300 includes an input port and M output ports, M is greater than or equal to 3 and less than or equal to N, the input port is matched with the multimode optical fiber 200, and separates a free space light beam received by the multimode optical fiber 200 into gaussian light beams of a plurality of modes, the output ports are matched with the single mode optical fiber and connected with the photodetector 400, and each output port corresponds to one optical fiber mode supported in the multimode optical fiber 200; the photo detector 400 includes M photo detectors 400 and is connected to the output end of the multi-mode demultiplexing module 300, and the photo detectors 400 include, but are not limited to, an optical direct detector and an optical coherent detector commonly used in an optical fiber communication system.
When the free space light beam is transmitted through turbulent atmosphere, the intensity, the phase and the transmission direction of the free space light beam are disturbed to generate random changes due to random uneven distribution of refractive index in the turbulent atmosphere, and the change condition is related to the relative sizes of the laser beam width W and the turbulent dimension L; when the ratio of 2W/L is less than or equal to 1, the turbulent flow mainly causes the light beam to drift randomly; when 2W/L =1, the turbulent flow randomly deflects the cross section of the light beam to form arrival angle fluctuation; when the 2W/L is more than or equal to 1, a plurality of turbulent eddies are contained in the cross section of the light beam, so that the intensity fluctuation, the phase fluctuation and the light beam expansion of the light beam are caused. I.e. under weak turbulence the refractive index changes little, but due to the large number of non-uniformities, the cumulative effects are significant beyond a certain distance, including beam drift, beam spread, fluctuation of angle of arrival, atmospheric flicker, etc. Therefore, the multimode fiber 200 is used for coupling and receiving the distortion light field fundamental mode and the high-order mode after the free space atmospheric turbulence transmission, so that the purposes of obtaining extra receiving optical power, improving the performance of the free space optical communication system under the actual atmospheric turbulence condition and reducing the interruption probability of the system communication are achieved. Meanwhile, the photoelectric detector 400 is used for detecting multi-mode parallel signals, so that the purposes of improving the receiving efficiency of the system, improving the communication stability and reducing the error rate are achieved.
An alternative implementation of this embodiment: as shown in fig. 2, the multimode fiber anti-turbulence free space optical communication system further includes an amplification processing module 500; the input end of the amplification processing module 500 is connected with the output end of the multimode fiber 200; the output end of the amplification processing module 500 is connected with the input end of the multimode demultiplexing module 300; for amplifying the spatial light beam received by the multimode optical fiber 200. The method specifically comprises the following steps:
the optical fiber coupling module 100, the multimode optical fiber 200, the multimode demultiplexing module 300 and the photodetector 400, wherein an amplification processing module 500 is arranged between the multimode optical fiber 200 and the multimode demultiplexing module 300, the amplification processing module 500 adopts a multimode optical fiber amplifier 4, and is compatible with the multimode optical fiber 200, and the number of supported modes are the same as those of the multimode optical fiber 200. After the free space light beam is coupled into the multimode optical fiber 200 through the light beam coupling module 100, the received light signal energy is amplified through the amplification processing module 500, so as to achieve the purpose of compensating the light power attenuation caused by free space atmospheric turbulence transmission; then, the multimode demultiplexing module 300 performs mode separation, and finally, the photodetector 400 performs parallel detection on the optical signals of each mode.
The free space light beam affected by the atmospheric turbulence at the receiving end in the free space optical communication is coupled in multiple modes by using the light beam coupling module 100 and received by using the multimode optical fiber 200, the free space light beam received in the multimode optical fiber 200 is amplified by the amplification processing module 500 to obtain the amplified space light beam, the space light beam is converted into a Gaussian mode of multiple modes by the multimode demultiplexing module 300 to realize mode separation, and then each mode is sent to the photoelectric detector 400 for parallel signal detection. The multimode optical fiber 200 is a multimode optical fiber 200 used in conventional optical fiber communication systems, and has a core diameter of typically 50 μm. Compared with a single-mode fiber (the diameter of the fiber core is about 9 mu m) and a few-mode fiber (the diameter of the fiber core is about 16 mu m), the multimode fiber 200 has a larger light receiving area, and the light receiving power under the free space atmospheric turbulence condition is greatly improved. Meanwhile, after free space optical turbulence transmission, the optical power loss is large, the received optical power can be amplified by the amplification processing module 500 after the multimode optical fiber 200 receives the optical power, the optical power loss caused by long-distance free space turbulence is compensated, and then the light beam received in the multimode optical fiber 200 is converted into a plurality of gaussian modes by the multimode demultiplexing module 300 to perform parallel signal detection. The amplification processing module 500 and the multimode fiber 200 are single-core fibers, and the fiber cores have matched diameters and can be directly connected, so that the purposes of further improving the system receiving efficiency, reducing the communication error rate and improving the anti-turbulent communication stability are achieved.
A multimode optical fiber turbulence-resistant free-space optical communication device, as shown in fig. 3, comprising the above multimode optical fiber turbulence-resistant free-space optical communication system, further comprising: a laser 1, the laser 1 being for emitting a laser beam; the input end of the modulation module is connected with the output end of the laser 1 and is used for modulating the laser beam into a laser signal; and the input end of the conversion module is connected with the output end of the intensity modulator 2 and is used for converting the laser signal into a space beam. The device also comprises a spatial light modulator 8, wherein the input end of the spatial light modulator 8 is connected with the output end of the conversion module and is used for enabling the spatial light beams to pass through the atmosphere turbulence; the output end of the spatial light modulator 8 is connected with the input end of a coupling module 100, and the modulation module comprises an intensity modulator 2 and a waveform generator 3; the input end of the intensity modulator 2 is respectively connected with the output ends of the laser 1 and the waveform generator 3. The conversion module comprises a polarization controller 6 and an optical fiber collimator 7 which are connected in sequence; the input end of the polarization controller 6 is connected with the output end of the intensity modulator 2; the output end of the optical fiber collimator 7 is connected with the input end of the spatial light modulator 8. The method specifically comprises the following steps:
the beam coupling module 100 uses an aspheric lens with a focal length of 18.4 mm; multimode optical fiber 200 uses OM 3 The multimode optical fiber 200 is a single-core optical fiber with a core diameter of 50 μm, and the multimode demultiplexing module 300 supports 3 optical fiber orbital angular momentum modes (OAM) using a mode demultiplexer based on optical fiber mode coupling 0 ，OAM +1 ，OAM -1 ) Demultiplexing of (2). The photodetector 400 uses a direct detection module with a bandwidth of 18GHz.
After continuous laser with the wavelength of 1550nm emitted by a laser 1 is modulated by an intensity modulator 2, a 16-QAM discrete multi-tone modulation signal of 72Gbit/s generated by an arbitrary waveform generator 3 is loaded; the modulated optical signal passes through a single-mode optical fiber amplifier 4 and a variable optical attenuator 5, and then the free space transmitting optical power is adjusted; then the optical signal passes through a polarization controller 6 and an optical fiber collimator 7, and the optical signal in the optical fiber is converted into a free space Gaussian beam carrying the signal, wherein the radius of the Gaussian beam is 3.2mm; the gaussian beam then passes through a spatial light modulator 8, the spatial light modulator 8 being used to load a random turbulence phase screen for simulation of atmospheric turbulence. The light beam after turbulence simulation passes through the reflector 9 and is transmitted in space1.5m. And finally received by the beam coupling module 100. The multimode optical fiber turbulence-resistant free space optical communication system is compatible with the signal modulation format and the signal demodulation algorithm of the existing optical fiber communication system. And due to the utilization of the traditional OM with the core diameter of 50 μm 3 The average received optical power of the multimode fiber 200 is 9.5dB higher than that of a single-mode fiber in theoretical simulation, and is 5.7dB higher than that of a few-mode fiber, so that the communication performance of the system can be remarkably improved.
Fig. 4 is a graph comparing the distribution of received optical power of a conventional single-mode fiber and a multimode fiber turbulence-resistant free-space optical communication system of the present embodiment at different turbulence intensities measured under the condition of the multimode fiber turbulence-resistant free-space optical communication device provided in fig. 3, comparing the received optical power fluctuation maps of the multimode fiber turbulence-resistant free-space optical communication system of the present embodiment and the conventional single-mode fiber receiving system at an emitted optical power of 4dBm, where (a) is a medium turbulence intensity D/r0= 8; (b) The received optical power fluctuation patterns for the two under the condition of stronger turbulence intensity D/r0= 16. Therefore, the anti-turbulence free space optical communication system utilizing the multimode optical fiber can obtain higher received optical power and has smaller power fluctuation range.
Fig. 5 is a graph showing the optical power and the error rate of the free-space optical communication system with turbulence resistance of the conventional single-mode optical fiber and the multimode optical fiber of this embodiment measured under the condition of the free-space optical communication device with turbulence resistance of the multimode optical fiber provided in fig. 3, comparing the communication error rate performance of the free-space optical communication system with turbulence resistance of the multimode optical fiber of this embodiment with that of the conventional single-mode optical fiber receiving system. The test signal is a 16-QAM discrete multi-tone modulation signal of 72Gbit/s, wherein (a) is a graph of emitted optical power and bit error rate of the two under the condition of medium turbulence intensity D/r0= 8; (b) Graph of emitted light power versus bit error rate for both medium turbulence intensity D/r0= 16. Therefore, under the same transmitting power, the error rate of the anti-turbulence free space optical communication system using the multimode optical fiber is lower, and the required transmitting optical power at the 20% decision threshold can be reduced by more than 6 dB.
In summary, the free space optical communication system with the multimode fiber anti-turbulence in the present embodiment has the following features:
(1) the multimode optical fiber 200 is used for directly receiving the light beam light field after the transmission light beam is distorted due to the atmospheric turbulence and carrying out multimode parallel signal detection, so that the purposes of improving the receiving efficiency of the system, improving the communication stability, reducing the error rate and reducing the light beam energy at the transmitting end can be achieved. (2) And an additional feedback system of a wavefront sensing and phase correction device is not needed, so that the complexity of the system can be reduced, and the real-time performance of the system can be improved. (3) Using multimode fiber 200 for reception can significantly reduce the size of the receiving system. (4) Compared with the few-mode multi-core fiber, the used multi-mode fiber 200 has simple and mature manufacturing process, only has a single fiber core, and a receiving optical path system is simpler and more efficient; meanwhile, the multimode optical fiber 200 can be directly connected with the multimode optical fiber amplifier 4 to compensate the long-distance free space transmission turbulent flow loss; the purposes of further improving the receiving efficiency of the system, reducing the communication error rate and improving the anti-turbulent flow communication stability are achieved. (5) The optical fiber communication device has high compatibility with the existing optical fiber communication technology, and can be combined with the traditional optical fiber communication technologies such as advanced modulation formats, wavelength division multiplexing and time division multiplexing, so that the free space optical communication capacity and the spectral efficiency can be more efficiently improved. Meanwhile, the single-mode optical fiber interface is provided, so that the optical fiber interface can be well fused with the existing single-mode optical fiber communication system.
The embodiment also provides a communication method of the free space optical communication system based on the anti-turbulence multimode optical fiber, which comprises the following steps: coupling the spatial light beam subjected to atmospheric turbulence into the multimode optical fiber 200; separating the spatial light beam received by the multimode fiber 200 into a plurality of gaussian light beams; and carrying out parallel signal detection on the Gaussian beams.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A multimode optical fiber turbulence-resistant free-space optical communication system, comprising:
a multimode optical fiber (200), the multimode optical fiber (200) for receiving a spatial light beam subjected to atmospheric turbulence;
a coupling module (100), an output end of the coupling module (100) being connected with an input end of a multimode optical fiber (200) for coupling the spatial beam subjected to atmospheric turbulence into the multimode optical fiber (200);
the multimode demultiplexing module (300), the input end of the multimode demultiplexing module (300) is connected with the output end of the multimode fiber (200), and the multimode demultiplexing module is used for separating the spatial light beam received by the multimode fiber (200) into a plurality of Gaussian light beams;
and the input end of the photoelectric detector (400) is connected with the output end of the multimode demultiplexing module (300) and is used for carrying out parallel signal detection on the Gaussian beam.
2. The multimode fiber turbulence-resistant free-space optical communication system of claim 1, wherein:
further comprises an amplification processing module (500);
the input end of the amplification processing module (500) is connected with the output end of the multimode optical fiber (200);
the output end of the amplification processing module (500) is connected with the input end of the multimode demultiplexing module (300);
for amplifying a spatial light beam received by a multimode optical fibre (200).
3. The multimode fiber turbulence-resistant free-space optical communication system of claim 1, wherein:
the multimode optical fiber (200) comprises N optical fiber modes, wherein N is more than or equal to 3, and N is an integer.
4. The multimode fiber turbulence resistant free-space optical communication system of claim 3, wherein:
the multi-mode demultiplexing module (300) comprises M output ports, wherein M is more than or equal to 3 and less than or equal to N, and M is an integer.
5. The multimode fiber turbulence resistant free-space optical communication system of claim 1, wherein:
the photodetector (400) includes an optical direct detector and an optical coherent detector.
6. An anti-turbulence free-space optical communication device for a multimode optical fiber, comprising the anti-turbulence free-space optical communication system for a multimode optical fiber according to any one of claims 1 to 5, further comprising:
a laser (1), the laser (1) being adapted to emit a laser beam;
the input end of the modulation module is connected with the output end of the laser (1) and is used for modulating the laser beam into a laser signal;
and the input end of the conversion module is connected with the output end of the intensity modulator (2) and is used for converting the laser signal into a space beam.
7. The multimode fiber turbulence-resistant free-space optical communications device of claim 6, wherein:
the device also comprises a spatial light modulator (8), wherein the input end of the spatial light modulator (8) is connected with the output end of the conversion module and is used for enabling the first Gaussian beam to pass through the atmosphere turbulence;
the output end of the spatial light modulator (8) is connected with the input end of the coupling module (100).
8. The multimode fiber turbulence-resistant free-space optical communications device of claim 6, wherein:
the modulation module comprises an intensity modulator (2) and a waveform generator (3);
the input end of the intensity modulator (2) is connected with the output ends of the laser (1) and the waveform generator (3) respectively.
9. The turbulence resistant free-space optical communication device of claim 6, wherein:
the conversion module comprises a polarization controller (6) and an optical fiber collimator (7) which are connected in sequence;
the input end of the polarization controller (6) is connected with the output end of the intensity modulator (2).
10. A communication method based on the free space optical communication system with the anti-turbulent flow of the multimode optical fiber according to any one of claims 1 to 5, characterized by comprising the following steps:
coupling the spatially light beam subjected to atmospheric turbulence into a multimode optical fiber (200);
splitting a spatial beam received by a multimode optical fiber (200) into a plurality of gaussian beams;
and carrying out parallel signal detection on the Gaussian beams.
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