JP7130175B2 - optical space communication device - Google Patents

Description

The present disclosure relates to a space optical communication device that communicates with a satellite.

A space optical communication device communicates with a satellite by emitting signal light into space. Since the optical space communication device uses signal light, it has a small spread angle and is excellent in confidentiality. In addition, the free-space optical communication device is capable of large-capacity communication in areas where fiber laying is difficult.

Signal light emitted from optical space communication has a small spread angle. Therefore, in order to establish communication with a satellite, the optical space communication device must acquire and track the satellite with high precision and emit signal light.

On the other hand, there is known a method of establishing communication by using light for initial supplementation separately from signal light for communication (for example, see Patent Document 1).

WO2019/026207

However, when the optical space communication device establishes communication using light for initial acquisition, acquisition and tracking becomes difficult if the satellite behaves unexpectedly after communication is established.

The present disclosure has been made to solve the above problems, and aims to provide an optical space communication device capable of supplemental tracking of satellites in real time without using light for initial acquisition. .

An optical space communication device according to the present disclosure includes a reference light source that outputs light corresponding to an injected current, a signal distribution unit that distributes the light output from the reference light source into a single local light and a plurality of signal lights, and a signal A phase modulation section that modulates the phase of the signal light obtained by the distribution section, an optical amplification section that amplifies the signal light modulated by the phase modulation section, and a signal light amplified by the optical amplification section and the signal distribution section. An optical phased array optical unit that multiplexes the local light obtained by and emits it into space, and a beat signal is obtained from the local light obtained by the signal light amplified by the optical amplifier and the local light obtained by the signal distribution unit, an optical receiving section for obtaining a baseband signal from the signal light and the signal light from the satellite; a first signal processing section for detecting baseband fluctuation based on the baseband signal obtained by the optical receiving section; Based on the fluctuation detected by the signal processing unit, the loop filter that controls the injection current to the reference light source so as to reduce the fluctuation, and the beat signal obtained by the optical receiving unit. a phase control unit for controlling the amount of modulation in the phase modulation unit so as to synchronize with the signal; a gimbal for controlling the operation of the optical phased array optical unit; a second signal processing unit that controls a gimbal to perform supplemental tracking of the satellite; and the optical phased array optical unit has a fiber collimator array composed of a plurality of fiber collimators into which signal light from the satellite is incident. , the second signal processing unit includes an intensity acquisition unit that acquires the reception intensity of the signal light incident on the fiber collimator, and based on the reception intensity acquired by the intensity acquisition unit, the center of gravity of the reception intensity in the fiber collimator array an irradiation position estimation unit for estimating the irradiation position of the signal light incident on the fiber collimator based on the center of gravity calculated by the center of gravity calculation unit; and the irradiation position estimated by the irradiation position estimation unit and a acquisition and tracking unit that controls the phase control unit and the gimbal to perform supplementary tracking of the satellite based on the prediction result of the prediction unit and the orbital information of the satellite. It is characterized by

According to the present disclosure, since it is configured as described above, it is possible to perform supplemental tracking of the satellite in real time without using light for initial acquisition.

1 is a diagram showing a configuration example of a free-space optical communication device according to Embodiment 1; FIG. 2 is a diagram showing a configuration example of a phase synchronization circuit according to Embodiment 1; FIG. 4 is a diagram showing a configuration example of an optical phased array optical unit according to Embodiment 1; FIG. 4 is a diagram illustrating a configuration example of a second signal processing unit according to Embodiment 1; FIG. 4 is a flow chart showing an operation example of the first signal processing unit and the loop filter in Embodiment 1. FIG. 7 is a flow chart showing an operation example of a second signal processing unit according to Embodiment 1; 4 is an image diagram showing signal light incident on the fiber collimator array in Embodiment 1. FIG. 8A and 8B are diagrams showing hardware configuration examples of the free-space optical communication device according to the first embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
Embodiment 1.
Hereinafter, the free-space optical communication device according to the first embodiment will be described in detail with reference to the drawings. In addition, Embodiment 1 shows a specific example of the present disclosure. Therefore, the shape, arrangement, material, and the like of each component are examples, and are not intended to limit the present disclosure. Each figure is a schematic diagram and is not strictly illustrated.

FIG. 1 is a diagram showing a configuration example of a free-space optical communication device according to Embodiment 1. As shown in FIG.
A space optical communication device communicates with a satellite (not shown) by emitting signal light (beam) into space. As shown in FIG. 1, the optical space communication device includes a light source section 1, a reference signal generation source 2, a plurality of element unit sections 3, an optical amplifier 4, an optical phased array optical section 5, a signal processing section (first signal processing section) 6, a loop filter 7, a satellite orbit information transmission section 8, a gimbal 9, and a signal processing section (second signal processing section) 10.

A light source unit 1 outputs a single local light and a plurality of signal lights. As shown in FIG. 1, the light source unit 1 includes a reference light source 11, a plurality of transmission light sources 12, a 1×2 coupler 13, a wavelength multiplexing coupler 14, an intensity modulator 15, a 2×1 wavelength multiplexing coupler 16, and a signal distribution coupler. 17.

The reference light source 11 outputs light. The light output from the reference light source 11 is light for phase synchronization (phase error detection). The reference light source 11 has an optical phase shifter and outputs light having a phase corresponding to the current injected from the loop filter 7 . The reference light source 11 is, for example, a laser light source.

The transmission light source 12 outputs signal light. The signal light output from the transmission light source 12 is light for signal transmission (for communication signals). Each transmission light source 12 outputs light having a wavelength different from that of the light output from the reference light source 11 and different from each other. The transmission light source 12 is, for example, a laser light source. The number of transmission light sources 12 is not limited as long as it is plural.

The 1×2 coupler 13 splits the light output from the reference light source 11 into signal light and local light. The 1×2 coupler 13 is, for example, a polarization maintaining filter coupler.

The wavelength multiplexing coupler 14 multiplexes the signal lights output from each transmission light source 12 . The wavelength multiplexing coupler 14 is configured by connecting, for example, DWDM (Dense Wavelength Division Multiplexing) filters in multiple stages.

The intensity modulator 15 intensity-modulates the signal light after being multiplexed by the wavelength multiplexing coupler 14 . That is, the intensity modulator 15 adds a data signal to the signal light after being multiplexed by the wavelength multiplexing coupler 14, for example, by an OOK (On-Off Keying) method. The intensity modulator 15 is, for example, a Mach-Zehnder modulator.

The 2×1 wavelength multiplexing coupler 16 multiplexes the signal light obtained by the 1×2 coupler 13 and the signal light intensity-modulated by the intensity modulator 15 .

The signal distribution coupler 17 distributes the signal light multiplexed by the 2×1 wavelength multiplexing coupler 16 into a plurality of signal lights. The distribution number of the signal distribution coupler 17 is equal to the number of the element unit sections 3 . The signal distribution coupler 17 is configured by connecting 1×2 couplers in multiple stages, for example. The signal light obtained by the signal distribution coupler 17 is output to the element unit sections 3 different from each other.

The 1×2 coupler 13 and the signal distribution coupler 17 constitute a “signal distribution unit that distributes the light output from the reference light source 11 into a single local light and a plurality of signal lights”.

A reference signal source 2 generates an electrical signal. The electrical signal generated by the reference signal source 2 is the reference signal. The reference signal source 2 is, for example, a signal generator.

The element unit section 3 uses the electrical signal generated by the reference signal generation source 2 to establish phase synchronization of the signal light output from the light source section 1 . The element unit section 3 includes, as shown in FIG. , a phase synchronization circuit 37 and a bandpass filter 38 .

The phase modulator 31 phase-modulates the signal light output from the signal distribution coupler 17 . The amount of phase shift imparted to the signal light by phase modulation by the phase modulator 31 has a correlation with the amount of frequency shift. The amount of frequency shift is determined by the electrical signal (phase error compensation signal) after phase synchronization is established by the phase synchronization circuit 37 . Phase modulator 31 is, for example, an LN modulator or an AO modulator.

The optical amplifier 32 amplifies the signal light phase-modulated by the phase modulator 31 . The optical amplifier 32 amplifies light according to the magnitude of the drive current supplied from the outside. The optical amplifier 32 is a semiconductor optical amplifier.

The polarization maintaining circulator 33 switches the output direction of light according to the input direction of the light. This polarization maintaining circulator 33 outputs the signal light amplified by the optical amplifier 32 to the optical phased array optical section 5 . Also, the polarization maintaining circulator 33 outputs the light from the optical phased array optical section 5 to the DWDM filter 34 .

The DWDM filter 34 wavelength-separates the light output from the polarization maintaining circulator 33 into phase synchronization component light and communication signal component light. The phase synchronization component light is light having the same wavelength as the light output from the reference light source 11 . The communication signal component light is light having the same wavelength as the signal light output from each transmission light source 12 . The communication signal component light obtained by the DWDM filter 34 is terminated.

The optical receiver 35 converts the light of the phase synchronization component obtained by the DWDM filter 34 into an electrical signal. That is, the optical receiver 35 detects the beat signal by performing heterodyne detection on the light (signal light and local light) reflected by the optical phased array optical unit 5 . Further, the optical receiver 35 performs homodyne detection on the light (signal light) reflected by the optical phased array optical unit 5 and the signal light (signal light from the satellite) incident on the optical phased array optical unit 5. to detect the baseband signal. The optical receiver 35 is, for example, a photodiode.

The signal amplifier 36 amplifies the electric signal (beat signal) obtained by the optical receiver 35 to a signal level detectable by the phase synchronization circuit 37 (loop filter 373). Signal amplifier 36 is, for example, an RF amplifier.

The phase synchronization circuit 37 compares the electrical signal amplified by the signal amplifier 36 with the electrical signal generated by the reference signal source 2 to establish phase synchronization. The phase synchronization circuit 37 includes a phase shifter 371, a phase comparator 372, a loop filter 373 and a VCO (Voltage Controlled Oscillator) 374, as shown in FIG.

The phase shifter 371 performs phase adjustment on the electrical signal generated by the reference signal source 2 . Further, when a control signal is generated by the signal processing section 10, the phase shifter 371 performs the phase adjustment according to the control signal.

The phase comparator 372 detects a phase error between the electrical signal after phase adjustment by the phase shifter 371 and the electrical signal after amplification by the signal amplifier 36 .

The loop filter 373 smoothes the signal (phase comparison signal) indicating the phase error detected by the phase comparator 372 .

The VCO 374 generates a high-frequency signal for equalizing the frequency of the electrical signal amplified by the signal amplifier 36 with the frequency of the electrical signal after phase adjustment by the phase shifter 371, based on the phase comparison signal smoothed by the loop filter 373. Generate. A phase error compensation signal (an electrical signal after establishing phase synchronization), which is a high-frequency signal generated by the VCO 374 , is output to the phase modulator 31 .

It should be noted that the signal amplifier 36 and the phase synchronization circuit 37 are "a phase control section that controls the amount of modulation in the phase modulation section so as to synchronize the beat signal with the reference signal based on the beat signal obtained by the optical receiving section 35." corresponds to

The bandpass filter 38 blocks signals in a specific frequency band among the electrical signals obtained by the optical receiver 35 . That is, the band-pass filter 38 cuts off beat signals generated by heterodyne detection of signal light and local light among the electrical signals obtained by the optical receiver 35 .

The optical amplifier 4 amplifies local light emitted from the light source unit 1 . Specifically, the optical amplifier 4 amplifies local light obtained by the 1×2 coupler 13 . The optical amplifier 4 is, for example, an erbium-doped optical fiber amplifier (EDFA).

The optical phased array optical unit 5 multiplexes the signal light after establishing phase synchronization by the element unit unit 3 with the local light after being amplified by the optical amplifier 4, and emits the combined light into space. Also, incoming light (signal light) from a target satellite is incident on the optical phased array optical unit 5 . The optical phased array optical section 5 includes a fiber collimator 51, a fiber collimator array 52 and a beam splitter 53, as shown in FIG.

The fiber collimator 51 collimates the local light amplified by the optical amplifier 4 .

The fiber collimator array 52 is an integrated transmitting/receiving element configured by arranging fiber collimators in an array. The fiber collimator array 52 multiplexes the signal light output from the polarization maintaining circulator 33 and the local light reflected from the beam splitter 53 at the end face of the fiber collimator. Then, the fiber collimator array 52 Fresnel-reflects part of the combined light on the end face of the fiber collimator. Light reflected by the fiber collimator array 52 is output to the polarization maintaining circulator 33 . Also, the fiber collimator array 52 converts the rest of the combined light into parallel light. Also, the fiber collimator array 52 passes the signal light from the satellite that has passed through the beam splitter 53 .

The beam splitter 53 reflects or passes incident light. The beam splitter 53 reflects local light collimated by the fiber collimator 51 toward the fiber collimator array 52 . Also, the beam splitter 53 emits the light collimated by the fiber collimator array 52 into space. Also, the beam splitter 53 passes signal light from the satellite.

The signal processing section 6 performs two processes on the signal output from the element unit section 3 . That is, the signal processing unit 6 detects baseband fluctuations based on the electrical signal (baseband signal) obtained by the bandpass filter 38 . Also, the signal processing unit 6 detects the received intensity of the signal light from the satellite based on the electric signal (baseband signal) obtained by the bandpass filter 38 .

Based on the baseband fluctuation detected by the signal processing unit 6, the loop filter 7 controls the injection current to the reference light source 11 so as to suppress (reduce) the fluctuation. Thereby, the loop filter 7 controls the phase of the light output by the reference light source 11 .

At this time, first, the loop filter 7 acquires information indicating the baseband fluctuation detected from the signal processing unit 6 . Then, the loop filter 7 determines whether or not there is fluctuation in the baseband from the acquired information. Then, when the loop filter 7 determines that there is fluctuation in the baseband, it transmits a signal to the reference light source 11 so as to control the phase of the light from the reference light source 11 by controlling the injection current to the reference light source 11. and terminate the process. On the other hand, when the loop filter 7 determines that there is no fluctuation in the baseband, it ends the processing.

The satellite orbital information transmission unit 8 transmits satellite orbital information based on orbital elements to the signal processing unit 10 .

The gimbal 9 controls the azimuth and elevation operations supporting the telescope (not shown) containing the optical phased array optical unit 5 based on the orbital information of the satellite, and scans the signal light emitted into space. Further, when a control signal is generated by the signal processing unit 10, the gimbal 9 controls the azimuth and elevation operations supporting the telescope according to the control signal.

Based on the received intensity of the signal light detected by the signal processing unit 6 and the orbital information calculated by the satellite orbital information transmitting unit 8, the signal processing unit 10 controls the phase shifter 371 of the phase synchronization circuit 37 and the gimbal 9. Generate control signals for control. Thereby, the signal processing unit 10 acquires and tracks the satellite. The signal processing unit 10 includes an intensity obtaining unit 101, a barycenter computing unit 102, an irradiation position estimating unit 103, a predicting unit 104, and a capture and tracking unit 105, as shown in FIG.

The intensity acquisition unit 101 acquires the reception intensity of signal light detected by the signal processing unit 6 .

The center-of-gravity calculator 102 calculates the center of gravity of the received intensities in the fiber collimator array 52 based on the received intensities acquired by the intensity acquirer 101 .

The irradiation position estimation unit 103 estimates the irradiation position of the signal light incident on the fiber collimator of the fiber collimator array 52 based on the center of gravity calculated by the center of gravity calculation unit 102 .

A prediction unit 104 predicts the motion of the satellite based on the irradiation position estimated by the irradiation position estimation unit 103 .

The acquisition and tracking unit 105 performs supplementary tracking of the satellite by controlling the phase shifter 371 and the gimbal 9 of the phase synchronization circuit 37 based on the prediction result from the prediction unit 104 and the orbital information of the satellite. At this time, the acquisition/tracking unit 105 compares the prediction result by the prediction unit 104 with the satellite orbit information, and determines whether acquisition/tracking correction is necessary. That is, the acquisition/tracking unit 105 determines whether additional control is necessary for the control of the gimbal 9 that is being performed based on the original trajectory information. Then, when the acquisition/tracking unit 105 determines that acquisition/tracking correction is necessary, it controls the phase shifter 371 and the gimbal 9 included in the phase synchronization circuit 37 . On the other hand, when the acquisition/tracking unit 105 determines that the acquisition/tracking correction is not necessary, the process ends.

Next, an operation example of the signal processing unit 6 and the loop filter 7 in Embodiment 1 will be described with reference to FIG.
As shown in FIG. 5, first, the signal processing unit 6 generates a received signal ( baseband signal) is acquired (step ST501). Here, the wavelength of the signal light reflected by the optical phased array optical section 5 and the wavelength of the signal light incident on the optical phased array optical section 5 from the satellite are the same wavelength, and a baseband signal can be obtained.
Next, signal processing section 6 detects baseband fluctuations from the baseband signal (step ST502). This baseband fluctuation is caused by the phase fluctuation of both signal lights.
Next, when the loop filter 7 determines that there is baseband fluctuation from the information indicating the fluctuation, the loop filter 7 controls the current injected to the reference light source 11 so as to reduce the fluctuation, thereby reducing the phase of the reference light source 11. is controlled (steps ST503 and ST504). On the other hand, when the loop filter 7 determines that there is no fluctuation in the baseband, it ends the processing.

As described above, the free-space optical communication device according to the first embodiment controls the current injected into the reference light source 11 so as to reduce the fluctuation while monitoring the fluctuation of the baseband, thereby reducing the phase noise of the received signal. can be reduced, and deterioration of phase synchronization accuracy can be suppressed.

Next, an operation example of the signal processing unit 10 according to Embodiment 1 will be described with reference to FIG.
The signal processing unit 10 controls scanning of the signal light so that the optical space communication device can acquire and track the satellite with high precision. It is assumed that the gimbal 9 controls the azimuth and elevation operations that support the telescope according to satellite orbit information obtained in advance.

In this case, as shown in FIG. 6, intensity acquisition section 101 first acquires the reception intensity of the signal light detected by signal processing section 6 (step ST601). That is, the intensity acquisition unit 101 acquires the received intensity of signal light for each fiber collimator included in the fiber collimator array 52 .

Next, the center of gravity computing section 102 computes the center of gravity of the received intensity in the fiber collimator array 52 based on the received intensity acquired by the intensity acquiring section 101 (step ST602). As shown in FIG. 7, the centroid calculator 102 can obtain the centroid of the received intensity from the received intensity of the signal light for each fiber collimator of the fiber collimator array 52 . Reference numeral 701 in FIG. 7 indicates signal light (received signal) incident on the fiber collimator array 52 .

Next, irradiation position estimation section 103 estimates the irradiation position of the signal light incident on the fiber collimator of fiber collimator array 52 based on the center of gravity calculated by center of gravity calculation section 102 (step ST603).

Next, prediction section 104 predicts the motion of the satellite based on the irradiation position estimated by irradiation position estimation section 103 (step ST604).

Next, the acquisition and tracking unit 105 performs supplemental tracking of the satellite by cooperatively controlling the phase shifter 371 and the gimbal 9 of the phase synchronization circuit 37 based on the prediction result from the prediction unit 104 and the satellite orbit information. . At this time, acquisition/tracking section 105 compares the prediction result of prediction section 104 with the trajectory information, and determines whether correction of acquisition/tracking is necessary (step ST605). That is, the acquisition/tracking unit 105 determines whether or not additional control is necessary for the operation control of the gimbal 9 that has been performed based on the original trajectory information. Then, when acquisition/tracking section 105 determines that acquisition/tracking correction is necessary, it controls phase shifter 371 and gimbal 9 of phase synchronization circuit 37 (step ST606). On the other hand, when the acquisition/tracking unit 105 determines that acquisition/tracking correction is not necessary, the process ends.

Here, the acquisition/tracking unit 105 can control the beam orientation angle (electronic scanning) by controlling the phase of the light with the phase shifter 371 . Also, the acquisition/tracking unit 105 can control the directivity angle of the beam by controlling the azimuth and elevation operations of the gimbal 9 . Therefore, the capture/tracker 105 can flexibly control the directivity angle of the beam by cooperatively controlling the phase shifter 371 and the gimbal 9 . At this time, the capture/tracking unit 105 performs rough tracking with the gimbal 9 and fine tracking with the phase shifter 371, thereby enabling highly accurate tracking. That is, the acquisition/tracking unit 105 scans the beam with the gimbal 9 based on the orbital information so that the beam hits the satellite. Further, in the optical space communication device, it is necessary to irradiate a beam attached with a communication signal to a detector (not shown) of a target satellite with high precision. Therefore, the acquisition/tracking unit 105 scans the beam by performing relative phase control of the optical phased array optical unit 5 using the phase shifter 371 .

As described above, the optical space communication apparatus according to Embodiment 1 estimates the movement of the satellite, and cooperatively controls the beam scanning angle control by the optical phased array optical unit 5 and the pointing control of the telescope from the estimation result. . As a result, this optical space communication device can acquire and track in a wide range and with high accuracy.

As described above, according to the first embodiment, the optical space communication device includes the reference light source 11 that outputs light corresponding to the injected current, and the light output from the reference light source 11 as a single local light and a plurality of lights. , a phase modulator 31 that modulates the phase of the signal light obtained by the signal splitter, and an optical amplifier 32 that amplifies the signal light after modulation by the phase modulator 31. , an optical phased array optical unit 5 that multiplexes the signal light after amplification by the optical amplifier 32 and the local light obtained by the signal distribution unit and emits it into space, and the signal light after amplification by the optical amplifier 32 and signal distribution An optical receiver 35 that obtains a beat signal from the local light obtained by the unit, obtains a baseband signal from the signal light and the signal light from the satellite, and based on the baseband signal obtained by the optical receiver 35, A signal processing unit 6 for detecting fluctuations in the baseband, a loop filter 7 for controlling the injection current to the reference light source 11 to reduce the fluctuations based on the fluctuations detected by the signal processing unit 6, and an optical receiving unit. a phase control unit that controls the modulation amount in the phase modulation unit so as to synchronize the beat signal with the reference signal based on the beat signal obtained by 35; a gimbal 9 that controls the operation of the optical phased array optical unit 5; A signal processing unit 10 is provided for controlling a phase control unit and a gimbal 9 based on the signal light from the satellite and the orbital information of the satellite to perform supplementary tracking of the satellite. As a result, the free-space optical communication apparatus according to Embodiment 1 can perform supplemental satellite tracking in real time without using light for initial acquisition. In addition, the optical space communication device according to Embodiment 1 can reduce the number of parts compared to the conventional configuration.

Finally, a hardware configuration example of the free-space optical communication device according to the first embodiment will be described with reference to FIG.
Each function of the signal processing section 6 , the loop filter 7 and the signal processing section 10 in the free space optical communication device is realized by the processing circuit 501 . The processing circuit 501 may be dedicated hardware, as shown in FIG. 8A, or a CPU (Central Processing Unit, central processing unit, It may be a processing device, an arithmetic device, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor) 502 .

When the processing circuit 501 is dedicated hardware, the processing circuit 501 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate). Array), or a combination thereof. The functions of the signal processing unit 6, the loop filter 7, and the signal processing unit 10 may be implemented individually by the processing circuit 501, or the functions of the respective units may be collectively implemented by the processing circuit 501. FIG.

When the processing circuit 501 is the CPU 502, the functions of the signal processing section 6, the loop filter 7 and the signal processing section 10 are implemented by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in the memory 503 . The processing circuit 501 reads out and executes a program stored in the memory 503 to realize the function of each unit. That is, the optical space communication device includes a memory 503 for storing a program that, when executed by the processing circuit 501, results in execution of the steps shown in FIGS. 5 and 6, for example. It can also be said that these programs cause a computer to execute the procedures and methods of the signal processing section 6, the loop filter 7, and the signal processing section 10. FIG. Here, as the memory 503, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically EPROM), Magnetic discs, flexible discs, optical discs, compact discs, mini discs, DVDs (Digital Versatile Discs), and the like are applicable.

The functions of the signal processing unit 6, the loop filter 7, and the signal processing unit 10 may be partially implemented by dedicated hardware and partially implemented by software or firmware. For example, the function of the signal processing unit 6 is realized by a processing circuit 501 as dedicated hardware, and the processing circuit 501 reads and executes programs stored in the memory 503 for the loop filter 7 and the signal processing unit 10. It is possible to realize the function by

Thus, the processing circuit 501 can implement each function described above by means of hardware, software, firmware, or a combination thereof.

It should be noted that any component of the embodiment can be modified, or any component of the embodiment can be omitted.

A space optical communication device according to the present disclosure enables supplemental tracking of a satellite in real time, and is suitable for use as a space optical communication device or the like that communicates with a satellite.

1 light source unit, 2 reference signal generation source, 3 element unit unit, 4 optical amplifier, 5 optical phased array optical unit, 6 signal processing unit (first signal processing unit), 7 loop filter, 8 satellite orbit information transmission unit, 9 gimbal, 10 signal processor (second signal processor), 11 reference light source, 12 transmission light source, 13 1×2 coupler, 14 wavelength multiplex coupler, 15 intensity modulator, 16 2×1 wavelength multiplex coupler, 17 signal Distributing coupler, 31 phase modulator (phase modulation section), 32 optical amplifier (optical amplification section), 33 polarization maintaining circulator, 34 DWDM filter, 35 optical receiving section, 36 signal amplifier, 37 phase synchronization circuit, 38 band pass filter, 51 fiber collimator, 52 fiber collimator array, 53 beam splitter, 101 intensity acquisition unit, 102 center of gravity calculation unit, 103 irradiation position estimation unit, 104 prediction unit, 105 acquisition and tracking unit, 371 phase shifter, 372 phase comparator, 373 loop filter, 374 VCO, 501 processing circuit, 502 CPU, 503 memory.

Claims (2)

a reference light source that outputs light corresponding to the injected current;
a signal distribution unit that distributes the light output from the reference light source into a single local light and a plurality of signal lights;
a phase modulation unit that modulates the phase of the signal light obtained by the signal distribution unit;
an optical amplifier that amplifies the signal light modulated by the phase modulator;
an optical phased array optical unit that multiplexes the signal light amplified by the optical amplification unit and the local light obtained by the signal distribution unit and emits the combined light into space;
an optical receiver that obtains a beat signal from the signal light amplified by the optical amplifier and local light obtained from the signal distributor, and obtains a baseband signal from the signal light and the signal light from the satellite;
a first signal processing unit that detects baseband fluctuations based on the baseband signal obtained by the optical receiving unit;
a loop filter that controls the injection current to the reference light source so as to reduce the fluctuation based on the fluctuation detected by the first signal processing unit;
a phase control unit that controls the amount of modulation in the phase modulation unit so as to synchronize the beat signal with a reference signal based on the beat signal obtained by the optical reception unit;
a gimbal for controlling the operation of the optical phased array optics;
a second signal processing unit that controls the phase control unit and the gimbal to perform supplemental tracking of the satellite based on the signal light from the satellite and the orbit information of the satellite;
The optical phased array optical unit has a fiber collimator array composed of a plurality of fiber collimators into which signal light from the satellite is incident,
The second signal processing unit is
an intensity acquisition unit that acquires the received intensity of the signal light incident on the fiber collimator;
a center-of-gravity computing unit that computes the center of gravity of the received intensity in the fiber collimator array based on the received intensity acquired by the intensity acquisition unit;
an irradiation position estimation unit that estimates an irradiation position of the signal light incident on the fiber collimator based on the center of gravity calculated by the center of gravity calculation unit;
a prediction unit that predicts the movement of the satellite based on the irradiation position estimated by the irradiation position estimation unit;
A free-space optical communication device, comprising: an acquisition and tracking unit that controls the phase control unit and the gimbal to perform supplemental tracking of the satellite based on the prediction result of the prediction unit and the orbit information of the satellite. . 2. The free-space optical communication device according to claim 1, wherein the optical phased array optical unit has a transmission/reception integrated fiber collimator array composed of a plurality of elements .

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