JP6734000B1 - Laser light control device, optical space communication device, and optical space communication system - Google Patents

Abstract

When the beam beam transmitted from the optical space communication device of the communication partner is received, from the light intensity detection unit (12) that detects the light intensity of the beam and the light intensity detected by the light intensity detection unit (12), Atmospheric structure constant calculation unit (15) for calculating an atmospheric structure constant that indicates the degree of disturbance of the refractive index of the atmosphere with the optical space communication device of the communication partner, and the atmospheric structure calculated by the atmospheric structure constant calculation unit (15) Based on a constant, a modulation amount calculation unit (16) that calculates the modulation amount of each phase of a plurality of laser beams, which are light beams into which the transmission target beam is divided, and a modulation amount calculation unit (16). The laser light controller (3) is configured so as to include a phase modulator (34) that modulates the phase of each laser light according to each modulation amount.

Description

The present invention relates to a laser light control device that modulates the phase of laser light, an optical space communication device, and an optical space communication system.

The following Patent Document 1 discloses an optical space transmission device that performs communication using light propagating in space.
The intensity of light propagating in space may fluctuate due to atmospheric fluctuations. The optical space transmission device disclosed in Patent Document 1 has a function of reducing fluctuations in light intensity due to atmospheric fluctuations. This optical space transmission device includes an optical system that guides received light to a light receiving element via a movable mirror, and a received light intensity detection circuit that detects the intensity of the received light received by the light receiving element. However, the angle of the movable mirror is controlled based on the intensity detected by the received light intensity detection circuit.

JP, 2005-341494, A

In the optical space transmission device disclosed in Patent Document 1, the movable mirror control circuit controls the angle of the movable mirror to reduce fluctuations in the intensity of the received light. However, since the control of the angle of the movable mirror is control by mechanical drive, it takes some time for the movable mirror control circuit to complete the control of the angle of the movable mirror, and the angle of the movable mirror is controlled. During the control, the intensity of the received light may further change.
In the optical space transmission device disclosed in Patent Document 1, if the intensity of the received light fluctuates further while controlling the angle of the movable mirror, the influence due to the fluctuation of the intensity of the received light cannot be reduced. There was a problem that it might happen.

The present invention has been made to solve the above problems, a laser light control device capable of reducing the fluctuation of the light intensity of the beam in a shorter time than performing control by mechanical driving, An object is to obtain an optical space communication device and an optical space communication system.

In the laser light control device according to the present invention, when the beam transmitted from the optical space communication device of the communication partner is received, the light intensity detection unit that detects the light intensity of the beam and the light intensity detection unit detects the light intensity. Each time, the light intensity is obtained, and from the obtained light intensities, the atmospheric structure constant calculation is performed to calculate the atmospheric structure constant indicating the degree of disorder of the refractive index of the atmosphere with the optical space communication device of the communication partner. Section, based on the atmospheric structure constant calculated by the atmospheric structure constant calculation unit, a modulation amount calculation unit that calculates the modulation amount of each phase of a plurality of laser light is a beam of the beam to be transmitted is divided, A phase modulation unit that modulates the phase of each laser beam according to each modulation amount calculated by the modulation amount calculation unit is provided.

According to the present invention, based on the atmospheric structure constant calculated by the atmospheric structure constant calculating unit, the modulation amount calculation for calculating the modulation amount of each phase of the plurality of laser beams, which are the light beams into which the beam to be transmitted is divided, is calculated. The laser light control device is configured so that the phase modulation unit modulates the phase of each laser light according to each modulation amount calculated by the modulation amount calculation unit. Therefore, the laser light control device according to the present invention can reduce the fluctuation of the light intensity of the beam in a shorter time than the control by mechanical driving.

FIG. 3 is a configuration diagram showing an optical space communication system according to the first embodiment. FIG. 3 is a configuration diagram showing a first optical space communication device 1 in the optical space communication system according to the first embodiment. 3 is a hardware configuration diagram showing hardware of an atmospheric structure constant calculation unit 15 and a modulation amount calculation unit 16 included in the laser light control device 3 according to the first embodiment. FIG. It is a hardware block diagram of a computer when a part of laser light control apparatus 3 is implement|achieved by software or firmware. It is explanatory drawing which shows a 1st table. And atmospheric structure constant Cn ^2, is an explanatory diagram showing a correspondence relationship between the magnitude of fluctuations in the light intensity of the beam propagating through the atmosphere. It is explanatory drawing which shows a 2nd table. Figure 8A is an explanatory diagram showing an example of arrangement of the laser beam _Lsr 1 _{~Lsr 19} synthesized by the beam combining unit 37, FIG. 8B, an example of arrangement of the laser beam _Lsr 1 _{~Lsr 19} synthesized by the beam combining unit 37 It is an explanatory view shown. FIG. 6 is a configuration diagram showing a first optical space communication device 1 in the optical space communication system according to the second embodiment. FIG. 10A is an explanatory view showing an example in which four light-receiving surfaces 24a, 24b, 24c, and 24d are uniformly irradiated with the beam condensed by the condenser lens 23, and FIG. 10B shows four light-receiving surfaces. It is explanatory drawing which shows the example which the beam condensed by the condensing lens 23 is not uniformly irradiated with respect to 24a, 24b, 24c, 24d.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.
FIG. 1 is a configuration diagram showing an optical space communication system according to the first embodiment.
In FIG. 1, a first optical space communication device 1 transmits/receives a beam to/from a second optical space communication device 2, which is a communication partner optical space communication device.
The second optical space communication device 2 transmits/receives a beam to/from the first optical space communication device 1 which is a communication partner optical space communication device.
The first optical space communication device 1 and the second optical space communication device 2 perform bidirectional information transmission by transmitting and receiving beams to and from each other through the atmosphere.

FIG. 2 is a configuration diagram showing the first optical space communication device 1 in the optical space communication system according to the first embodiment.
The configuration of the second optical space communication device 2 is similar to the configuration of the first optical space communication device 1, and the configuration diagram showing the second optical space communication device 2 is FIG.
The first optical space communication device 1 includes a laser light control device 3 as shown in FIG.
As shown in FIG. 2, the laser light control device 3 includes a light intensity detector 12, an atmospheric structure constant calculator 15, a modulation amount calculator 16, and a phase modulator 34.
FIG. 3 is a hardware configuration diagram showing the hardware of the atmospheric structure constant calculation unit 15 and the modulation amount calculation unit 16 included in the laser light control device 3 according to the first embodiment.

2, the receiver 10 includes a receiver 11, a light intensity detector 12, an atmospheric structure constant calculator 15, and a modulation amount calculator 16.
The receiving unit 11 receives the beam transmitted from the second optical space communication device 2, and outputs the received beam to a condenser lens 13 of the light intensity detecting unit 12 described later.
The light intensity detector 12 includes a condenser lens 13 and a first photodiode 14.
The light intensity detector 12 detects the light intensity of the beam received by the receiver 11.
The condenser lens 13 condenses the beam output from the receiver 11 on a light receiving surface 14a of the first photodiode 14 described later.
The first photodiode 14 has a light receiving surface 14a.
The first photodiode 14 converts the beam condensed on the light receiving surface 14a by the condenser lens 13 into an electric signal, and is directly proportional to the light intensity of the beam condensed on the light receiving surface 14a as the electric signal. The current I _PD is output to each of the atmospheric structure constant calculation unit 15 and the phase acquisition unit 18 of the modulation amount calculation unit 16 described later.
Further, the first photodiode 14 outputs the current I _PD to a demodulator (not shown). A demodulator (not shown) demodulates the information superimposed on the beam transmitted from the second optical space communication device 2 from the current I _PD .

The atmospheric structure constant calculation unit 15 is realized by, for example, the atmospheric structure constant calculation circuit 41 shown in FIG.
The atmospheric structure constant calculation unit 15 uses the light intensity detected by the light intensity detection unit 12 to determine the degree of disorder of the refractive index of the atmosphere between the first optical space communication device 1 and the second optical space communication device 2. The atmospheric structure constant Cn ² shown is calculated.
Specifically, the atmospheric structure constant calculation unit 15 converts the output current I _PD into the power P _PD every time the current I _PD is output from the first photodiode 14, and the power P _PD is, for example, Store in internal memory.
The atmospheric structure constant calculator 15 calculates the atmospheric structure constant Cn ² based on, for example, the plurality of electric powers P _PD stored in the internal memory.
The atmospheric structure constant calculation unit 15 outputs the calculated atmospheric structure constant Cn ² to the phase acquisition unit 18 of the modulation amount calculation unit 16 described later.

The modulation amount calculation unit 16 includes a table storage unit 17, a phase acquisition unit 18, and a phase difference calculation unit 19.
The modulation amount calculator 16 calculates the phase of each of the _M laser beams Lsr _{1 to} Lsr _M output from the beam splitter 33, which will be described later, based on the atmospheric structure constant Cn ² calculated by the atmospheric structure constant calculator 15. The modulation amount Δφ _m of φ _m is calculated. m=1,..., M, and M is an integer of 2 or more.

The table storage unit 17 is realized by, for example, the table storage circuit 42 shown in FIG.
The table storage unit 17 stores a first table showing a correspondence relationship between _N atmospheric structure constants Cn ₁ ^{2 to} Cn _N ² and respective phases φ _m in the _M laser lights Lsr _{1 to} Lsr _M. ing. N is an integer of 2 or more.
The table storage unit 17 shows a second relation indicating the correspondence between the K currents I _{PD1 to} I _PDK that are directly proportional to the light intensity of the beam and the respective phases φ _m in the _M laser lights Lsr _{1 to} Lsr _M. Stores the table. K is an integer of 2 or more.

The phase acquisition unit 18 is realized by, for example, the phase acquisition circuit 43 shown in FIG.
The phase acquisition unit 18 uses the first table stored in the table storage unit 17 to generate M laser beams Lsr _{1 to} Lsr corresponding to the atmospheric structure constant Cn ² calculated by the atmospheric structure constant calculation unit 15. Obtain each phase φ _m in _M as the first phase φ _1,m .
The phase acquisition unit 18 uses the second table stored in the table storage unit 17 to generate M laser beams corresponding to the current I _PD that is directly proportional to the light intensity detected by the light intensity detection unit 12. Each phase φ _m in Lsr _{1 to} Lsr _M is acquired as the second phase φ _2,m .
The phase acquisition unit 18 outputs each of the _first phases φ _{1,1 to} φ _{1 ,M} and the second phases φ _{2,1 to} φ _2,M to the phase difference calculation unit 19.

The phase difference calculation unit 19 is realized by, for example, the phase difference calculation circuit 44 shown in FIG.
The phase difference calculation unit 19 acquires the _first phase acquired by the phase acquisition unit 18 as the modulation amount Δφ _m of each phase φ _{m in} the _M laser beams Lsr _{1 to} Lsr _M output from the beam splitter 33. The phase difference between φ _1,m and the second phase φ _2,m acquired by the phase acquisition unit 18 is calculated.
The phase difference calculator 19 outputs the calculated modulation amount Δφ _m to the optical phase modulator 34-m of the phase modulator 34, which will be described later.

The transmitter 30 includes a power supply 31, a reference laser 32, a beam splitter 33, a phase modulator 34, and a transmitter 35.
The power supply 31 supplies driving power to the first photodiode 14, the atmospheric structure constant calculation unit 15, the modulation amount calculation unit 16, the reference laser 32, the phase modulation unit 34, and the transmission unit 35 of the light intensity detection unit 12. It outputs to each of the amplifiers 36.

The reference laser 32 oscillates a beam to be transmitted and outputs the oscillated beam to the beam splitting unit 33.
The beam splitter 33 is realized by, for example, a beam splitter.
The beam splitter 33 splits the beam output from the reference laser 32 into M beams, and outputs each of the split laser beams Lsr _{1 to} Lsr _M to the optical phase modulator 34-m of the phase modulator 34. To do.

The phase modulator 34 includes M optical phase modulators 34-1 to 34-M.
The phase modulation unit 34 according to the _M modulation amounts Δφ _{1 to} Δφ M calculated by the modulation amount calculation unit 16, the respective phase φ in the _M laser beams Lsr _{1 to} Lsr _M output from the beam splitter 33. Modulate _m .
The optical phase modulator 34-m modulates the phase φ _m of the laser light Lsr _m output from the beam splitter 33 according to the modulation amount Δφ _m calculated by the phase difference calculation unit 19 of the modulation amount calculation unit 16.
The optical phase modulator 34-m outputs the laser beam Lsr _m after the phase modulation to be described later optical amplifiers 36-m of the transmitter 35.

The transmitter 35 includes an optical amplifier 36, a beam combiner 37, and a beam transmitter 38.
The transmitter 35 generates a beam from the M pieces of laser light Lsr _{1 to} Lsr _M whose phases are modulated by the phase modulator 34, and transmits the generated beam to the second optical space communication device 2 through the atmosphere. Send.
The optical amplification unit 36 includes M optical amplifiers 36-1 to 36-M.
The optical amplification unit 36 amplifies each of the _M laser beams Lsr _{1 to} Lsr _M whose phase is modulated by the phase modulation unit 34.
Optical amplifiers 36-m, the laser light Lsr _m after the phase-modulated output from the optical phase modulator 34-m amplifies and outputs the laser light Lsr _m after amplification to the beam combining unit 37.

The beam combiner 37 is realized by, for example, a beam combiner.
The beam combiner 37 generates a beam by combining the _M laser beams Lsr _{1 to} Lsr _M output from the optical amplifiers 36-1 to 36-M, and outputs the generated beam to the beam transmitter 38. ..
The beam transmitter 38 transmits the beam output from the beam combiner 37 to the second optical space communication device 2 via the atmosphere.

In FIG. 2, each of the atmospheric structure constant calculation unit 15, the table storage unit 17, the phase acquisition unit 18, and the phase difference calculation unit 19, which are some of the constituent elements of the laser light control device 3, are dedicated as shown in FIG. It is supposed to be realized by the hardware of. That is, it is assumed that the laser light control device 3 is realized by the atmospheric structure constant calculation circuit 41, the table storage circuit 42, the phase acquisition circuit 43, and the phase difference calculation circuit 44.
Here, the table storage circuit 42 is, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically readable memory). Alternatively, a volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc) is applicable.
Further, each of the atmospheric structure constant calculation circuit 41, the phase acquisition circuit 43, and the phase difference calculation circuit 44 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, or an ASIC (Application Specific Integrated Circuit). , FPGA (Field-Programmable Gate Array), or a combination thereof.

Some of the components of the laser light control device 3 are not limited to those realized by dedicated hardware, and some of the laser light control device 3 may be software, firmware, or a combination of software and firmware. May be realized by.
Software or firmware is stored in the memory of the computer as a program. The computer means hardware that executes a program, and corresponds to, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor). To do.
FIG. 4 is a hardware configuration diagram of a computer when a part of the laser light control device 3 is realized by software, firmware, or the like.
When a part of the laser light control device 3 is realized by software, firmware or the like, the table storage unit 17 is configured on the memory 51 of the computer. A program for causing a computer to execute the processing procedures of the atmospheric structure constant calculation unit 15, the phase acquisition unit 18, and the phase difference calculation unit 19 is stored in the memory 51. Then, the processor 52 of the computer executes the program stored in the memory 51.

Next, the operation of the optical space communication system shown in FIG. 1 will be described.
The first optical space communication device 1 and the second optical space communication device 2 perform bidirectional information transmission by transmitting and receiving beams to and from each other through the atmosphere.
Startup space optical communication system includes a first optical space communication apparatus 1 optical phase modulator 34-m (m = 1, ···, M) phase phi _m of the laser beam Lsr _m outputted from the initial Set to the value φ _m,ini . The phase phi _m of the laser beam Lsr _m outputted from the second optical space communication apparatus 2 optical phase modulator 34-m is set to an initial value phi _{m, ini.}
The initial value φ _m,ini may be stored in, for example, the internal memory of the optical phase modulator 34-m, may be stored outside the first optical space communication device 1, or may be stored in the second optical space communication device 2. It may be given from outside.
The initial value φ _m,ini stored in the internal memory of the optical phase modulator 34-m of the first optical space communication apparatus 1 and the optical phase modulator 34-m of the second optical space communication apparatus 2 are stored. The initial value φ _m,ini stored in the internal memory of is the same value.

The operation of the first optical space communication device 1 shown in FIG. 2 will be described below. The operation of the second space optical communication apparatus 2 is the same as the operation of the first space optical communication apparatus 1, and the description thereof will be omitted.
The reference laser 32 oscillates a beam to be transmitted and outputs the oscillated beam to the beam splitting unit 33.
Information transmitted to the second optical space communication device 2 is superimposed on the beam output from the reference laser 32 to the beam splitter 33 by a modulator (not shown). Alternatively, the reference laser 32 outputs to the beam splitting unit 33 a beam on which the information transmitted to the second optical space communication device 2 is superimposed.

When the beam splitting unit 33 receives the beam from the reference laser 32, the beam splitting unit 33 splits the beam into M beams, and each of the M split laser beams Lsr _{1 to} Lsr _M is subjected to optical phase modulation in the phase modulating unit 34. It outputs to each of the units 34-1 to 34-M.
The laser optical phase modulator 34-m is to set the phase phi _m of the laser beam Lsr _m outputted from the beam splitting unit 33 to an initial value phi _{m, ini,} and sets the phase phi _m to an initial value phi _{m, ini} outputs light Lsr _m to the optical amplifier 36-m.

Optical amplifiers 36-m receives the laser beam Lsr _m from the optical phase modulator 34-m, and amplifies the laser light Lsr _m, and outputs a laser beam Lsr _m after amplification to the beam combining unit 37.
Upon receiving the _M laser beams Lsr _{1 to} Lsr M from the optical amplifiers 36-1 to 36-M, the beam combining unit 37 generates a beam by combining the _M laser beams Lsr _{1 to} Lsr _M , The generated beam is output to the beam transmitter 38.
FIG. 8A is an explanatory diagram showing an arrangement example of the laser beams Lsr _{1 to} Lsr ₁₉ combined by the beam combining unit 37. In FIG. 8A, M=19.
The beam transmitter 38 transmits the beam output from the beam combiner 37 to the second optical space communication device 2 via the atmosphere.

The receiving unit 11 of the first space optical communication apparatus 1 receives the beam transmitted from the second space optical communication apparatus 2.
The receiver 11 outputs the received beam to the condenser lens 13 of the light intensity detector 12.

Upon receiving the beam from the receiver 11, the condenser lens 13 of the light intensity detector 12 condenses the beam on the light receiving surface 14 a of the first photodiode 14.
The first photodiode 14 converts the beam condensed on the light receiving surface 14a by the condenser lens 13 into an electric signal.
The first photodiode 14 outputs, as an electric signal, a current I _PD , which is directly proportional to the light intensity of the beam focused on the light receiving surface 14 a, to each of the atmospheric structure constant calculation unit 15 and the phase acquisition unit 18.
Further, the first photodiode 14 outputs the current I _PD to a demodulator (not shown).

The atmospheric structure constant calculation unit 15 converts the output current I _PD into the power P _PD each time the current I _PD is output from the first photodiode 14, and stores the power P _{PD in,} for example, an internal memory. ..
In the first optical space communication apparatus 1 shown in FIG. 2, it is assumed that the receiving unit 11 receives a beam at a time interval Δt of several seconds, for example. In this case, the first photodiode 14 outputs each of the currents I _PD of the time interval Δt to the atmospheric structure constant calculation unit 15 and the phase acquisition unit 18, and the atmospheric structure constant calculation unit 15 outputs the time interval Δt of the time interval Δt. Each of the powers P _PD is stored in, for example, an internal memory.

When the atmospheric structure constant calculation unit 15 stores the electric power P _PD within a fixed time in, for example, an internal memory, the atmospheric structure constant calculation unit 15 acquires the electric power P _PD within the fixed time from the internal memory. For example, if the fixed time is 10 minutes and Δt=1 [seconds], the atmospheric structure constant calculation unit 15 acquires 600 pieces of electric power P _PD from the internal memory.
Hereinafter, it is assumed that the atmospheric structure constant calculation unit 15 acquires the power P _PD,g (g=1, 2,..., G) from the internal memory. g is a variable that identifies the power _{P PD} acquired, G is the number of acquisition of the power _{P PD,} for example, a G = 600.

式（１）及び式（２）において、ｌｏｇ（ｘ）は、ｘの対数を示す数学記号である。
式（１）は、電力Ｐ_ＰＤ，１の対数〜Ｐ_ＰＤ，Ｇの対数の平均値を算出するものであり、式（３）は、Ｒｅｓｕｌｔ_２，１〜Ｒｅｓｕｌｔ_２，Ｇの平均値を算出するものである。The atmospheric structure constant calculation unit 15 uses the electric powers P _{PD,1 to} P _PD,G acquired from the internal memory to perform the calculations shown in the following formulas (1) to (3), thereby obtaining the calculation result Result ₃ . obtain.

In Expressions (1) and (2), log(x) is a mathematical symbol indicating the logarithm of x.
Formula (1) calculates the average value of the logarithm of power P _PD,1 to logarithm of P _PD,G , and formula (3) calculates the average value of Result _{2,1 to} Result _2,G. To do.

式（４）において、Ｄは、受信部１１における受信開口径、Ｌは、第１の光空間通信装置１と第２の光空間通信装置２との間の距離、ｋは、波数である。
受信開口径Ｄ、距離Ｌ及び波数ｋのそれぞれは、既値であり、例えば、大気構造定数算出部１５の内部メモリに格納されていてもよいし、図２に示す第１の光空間通信装置１の外部から与えられるものであってもよい。
大気構造定数算出部１５は、算出した大気構造定数Ｃｎ^２を位相取得部１８に出力する。Next, the atmospheric structure constant calculator 15 calculates the atmospheric structure constant Cn ² by substituting the calculation result Result ₃ into the following equation (4).

In Expression (4), D is the receiving aperture diameter in the receiving unit 11, L is the distance between the first optical space communication device 1 and the second optical space communication device 2, and k is the wave number.
Each of the reception aperture diameter D, the distance L, and the wave number k is an existing value and may be stored in, for example, the internal memory of the atmospheric structure constant calculation unit 15, or the first optical space communication device shown in FIG. 1 may be given from the outside.
The atmospheric structure constant calculation unit 15 outputs the calculated atmospheric structure constant Cn ² to the phase acquisition unit 18.

The table storage unit 17 stores a first table and a second table.
The first table, as shown in FIG. 5, the N number of atmospheric structure constant _Cn ¹ 2 _{to Cn} ^{N 2,} records the correspondence relation between each of the phases phi _m in the M laser beam _Lsr 1 ～Lsr _M doing. And N number of atmospheric structure constant _Cn ¹ 2 _{to Cn} ^{N 2,} correspondence between each of the phase phi _m in the M laser beam _Lsr 1 _{~Lsr M,} for example, is calculated by computer simulation.
FIG. 5 is an explanatory diagram showing the first table.
In Figure 5, for example, as the phase phi ₁ to [phi] _M which correspond to the atmospheric structure constant ^{_{Cn 1 2, θ 1, θ}} 2, θ 3, ···, θ 4 is recorded in the first table , as the phase phi ₁ to [phi] _M which correspond to the atmospheric structure constant ^{_{Cn 2 2, θ 5, θ}} 6, θ 7, ···, θ 8 is recorded in the first table.
The current atmospheric structure constant, for example if atmospheric structure constant Cn ₁ ^2, the phase phi ₁ to [phi] _M which correspond to the atmospheric structure constant Cn ₁ ^2, to suppress the variation of the light intensity of the beam propagating through the atmosphere It is a possible phase.
Further, if the current atmospheric structure constant is, for example, the atmospheric structure constant Cn ₂ ² , the phases φ _{1 to} φ _M corresponding to the atmospheric structure constant Cn ₂ ² indicate fluctuations in the light intensity of the beam propagating in the atmosphere. This is the phase that can be suppressed.
FIG. 6 is an explanatory diagram showing a correspondence relationship between the atmospheric structure constant Cn ² and the magnitude of fluctuation of the light intensity of the beam propagating in the atmosphere.

The second table, as shown in FIG. 7, and the K current _I PD1 _{~I PDK} which is directly proportional with the light intensity of the beam, and each of the phases phi _m in the M laser beam _Lsr 1 _{~Lsr M} The correspondence relationship of is recorded. The correspondence between the K currents I _{PD1 to} I _PDK and the respective phases φ _m in the _M laser lights Lsr _{1 to} Lsr _M is calculated by computer simulation, for example.
FIG. 7 is an explanatory diagram showing the second table.
In FIG. 7, for example, θ ₂₁ , θ ₂₂ , θ ₂₃ ,..., θ ₂₄ are stored in the second table as the phases φ ₁ to φ _M corresponding to the current I _PD1 . For example, θ ₂₅ , θ ₂₆ , θ ₂₇ ,..., θ ₂₈ are stored in the second table as the phases φ ₁ to φ _M corresponding to the current I _PD2 .

When the phase acquisition unit 18 receives the atmospheric structure constant Cn ² from the atmospheric structure constant calculation unit 15, from the first table stored in the table storage unit 17, the phase acquisition unit 18 outputs the M number of Ms corresponding to the atmospheric structure constant Cn ² . Each phase φ _m in the laser beams Lsr _{1 to} Lsr _M is acquired as the first phase φ _1,m .
Specifically, the phase obtaining unit 18, in the atmosphere structure constant Cn ₁ ² to Cn _N ² stored in the first table, identifies the closest air structure constant and atmospheric structure constant Cn ^2.
The phase acquisition unit 18 acquires, from the first table, each phase φ _m in the _M laser beams Lsr _{1 to} Lsr _M corresponding to the specified atmospheric structure constant as the first phase φ _1,m . ..
For example, by the specified atmospheric structure constant, if atmospheric structure constant _Cn ^{3 2,} phase acquisition unit 18, as the first phase _{φ 1,1 ~φ 1, M, θ} 9, θ 10, θ 11, · ..., to get the θ _12.
The phase acquisition unit 18 outputs the acquired M first phases φ _{1,1 to} φ _{1 ,M} to the phase difference calculation unit 19.

When the phase acquisition unit 18 receives the current I _PD from the first photodiode 14, the phase acquisition unit 18 reads the M laser beams Lsr ₁ corresponding to the current I _PD from the second table stored in the table storage unit 17. Obtain each phase φ _m in ˜Lsr _M as a _second phase φ _2,m .
Current _{I PD,} the power _P PD, _{1 to P PD,} may be any one of a current of the conversion of G-number of current _{I PD} of _G, an average value of G number of current _{I PD} It may be.
Specifically, the phase acquisition unit 18 identifies the current closest to the current I _PD among the currents I _{PD1 to} I _PDK stored in the second table.
The phase acquisition unit 18 acquires, from the second table, the respective phases φ _m in the _M laser beams Lsr _{1 to} Lsr _M corresponding to the specified current as the second phases φ _2,m .
For example, if the identified current is the current I _PD2 , the phase acquisition unit 18 sets θ ₂₅ , θ ₂₅ , θ ₂₇ ,..., θ ₂₈ as the _second phases φ _{2,1 to} φ _2,M. To get
The phase acquisition unit 18 outputs the acquired M second phases φ _{2,1 to} φ _2,M to the phase difference calculation unit 19.

位相差算出部１９は、算出した変調量Δφ_１〜Δφ_Ｍのそれぞれを、位相変調部３４における光位相変調器３４−１〜３４−Ｍのそれぞれに出力する。The phase difference calculation unit 19 determines the phase as shown in the following equation (5) as the modulation amount Δφ _m of each phase φ _{m in} the _M laser beams Lsr _{1 to} Lsr _M output from the beam splitter 33. The phase difference between the first phase φ _1,m and the second phase φ _2,m output from the acquisition unit 18 is calculated.

The phase difference calculator 19 outputs each of the calculated modulation amounts Δφ _{1 to} Δφ _M to each of the optical phase modulators 34-1 to 34-M in the phase modulator 34.

The reference laser 32 oscillates a beam to be transmitted and outputs the oscillated beam to the beam splitting unit 33.
Information transmitted to the second optical space communication device 2 is superimposed on the beam output from the reference laser 32 to the beam splitter 33 by a modulator (not shown). Alternatively, the reference laser 32 outputs to the beam splitting unit 33 a beam on which the information transmitted to the second optical space communication device 2 is superimposed.
When the beam splitting unit 33 receives the beam from the reference laser 32, the beam splitting unit 33 splits the beam into M beams, and each of the M split laser beams Lsr _{1 to} Lsr _M is subjected to optical phase modulation in the phase modulating unit 34. It outputs to each of the units 34-1 to 34-M.

式（６）において、左辺のφ_ｍは、位相変調部３４による変調後の位相である。右辺のφ_ｍは、現在の位相であり、例えば、起動後、最初の位相変調であれば、初期値φ_{ｍ，ｉｎｉ}である。
光位相変調器３４−ｍは、位相変調後のレーザ光Ｌｓｒ_ｍを送信部３５の光増幅器３６−ｍに出力する。
位相変調後のレーザ光Ｌｓｒ_１〜Ｌｓｒ_Ｍにおける位相φ_１〜φ_Ｍは、大気構造定数Ｃｎ_１ ^２と対応している位相φ_１〜φ_Ｍであり、大気を伝搬するビームの光強度の変動を抑制することが可能な位相である。Upon receiving the _M modulation amounts Δφ _{1 to} Δφ M from the modulation amount calculation unit 16, the phase modulation unit 34 outputs the M laser beams output from the beam splitting unit 33 according to the _M modulation amounts Δφ _{1 to} Δφ _M. The respective phases φ _m of the lights Lsr _{1 to} Lsr _M are modulated.
That is, the optical phase modulator 34-m outputs the laser light Lsr _m output from the beam splitter 33 according to the modulation amount Δφ _m output from the phase difference calculator 19 as shown in the following equation (6). Modulate the phase φ _m .

In Expression (6), φ _{m on} the left side is the phase after modulation by the phase modulator 34. Φ _m on the right side is the current phase, and is, for example, the initial value φ _m,ini for the first phase modulation after activation.
The optical phase modulator 34-m outputs the laser beam Lsr _m after the phase modulation to the optical amplifier 36-m of the transmitter 35.
Phase phi ₁ to [phi] _M of the laser beam _Lsr 1 _{~Lsr M} after the phase modulation is the phase phi ₁ to [phi] _M which correspond to the atmospheric structure constant _Cn ^{1 2,} variations in the light intensity of the beam propagating through the atmosphere Is a phase that can suppress.

Optical amplifiers 36-m receives the laser beam Lsr _m from the optical phase modulator 34-m, and amplifies the laser light Lsr _m, and outputs a laser beam Lsr _m after amplification to the beam combining unit 37.
Upon receiving the _M laser beams Lsr _{1 to} Lsr M from the optical amplifiers 36-1 to 36-M, the beam combining unit 37 generates a beam by combining the _M laser beams Lsr _{1 to} Lsr _M , The generated beam is output to the beam transmitter 38.
FIG. 8B is an explanatory diagram showing an arrangement example of the laser lights Lsr _{1 to} Lsr ₁₉ combined by the beam combiner 37. In FIG. 8B, M=19.
A laser light _Lsr 1 _{~Lsr 19} shown in Figure 8A, is compared with the laser beam _Lsr 1 _{~Lsr 19} shown in FIG. 8B, in the figure, the difference in shading in the laser beam _Lsr 1 _{~Lsr 19} is the difference in phase It represents.
The beam transmitter 38 transmits the beam output from the beam combiner 37 to the second optical space communication device 2 via the atmosphere.

In the first embodiment described above, based on the atmospheric structure constant calculated by the atmospheric structure constant calculating unit 15, the modulation amount of each phase of the plurality of laser beams, which are the beams into which the beam to be transmitted is divided, is calculated. The laser light control device 3 is configured to include the modulation amount calculation unit 16 so that the phase modulation unit 34 modulates the phase of each laser light according to each modulation amount calculated by the modulation amount calculation unit 16. Therefore, the laser light control device 3 can reduce the fluctuation of the light intensity of the beam in a shorter time than the control by mechanical driving.

Embodiment 2.
In the second embodiment, the light intensity detection units 21 in the first optical space communication device 1 and the second optical space communication device 2 respectively include the second photodiode 24 in addition to the first photodiode 14. An optical space communication system provided will be described.

FIG. 9 is a configuration diagram showing the first optical space communication device 1 in the optical space communication system according to the second embodiment.
The configuration of the second optical space communication device 2 is the same as the configuration of the first optical space communication device 1, and the configuration diagram showing the second optical space communication device 2 is FIG. In FIG. 9, the same reference numerals as those in FIG.
The light intensity detector 21 includes a beam splitter 22, a condenser lens 13, a first photodiode 14, a condenser lens 23, and a second photodiode 24.
The beam splitter 22 is realized by, for example, a beam splitter.
The beam splitting unit 22 splits the beam received by the receiving unit 11 into two, outputs one beam to the condensing lens 13, and outputs the other beam to the condensing lens 23.
The condenser lens 23 condenses the beam output from the beam splitter 22 on light receiving surfaces 24a, 24b, 24c, and 24d of the second photodiode 24, which will be described later.

The second photodiode 24 is realized by, for example, a quadrant photo diode (QPD) having four light receiving surfaces 24a, 24b, 24c, and 24d.
The second photodiode 24 detects the light intensities of the beams irradiated on the respective light receiving surfaces 24a, 24b, 24c, and 24d among the beams received by the receiving unit 11.
The second photodiode 24 outputs a current I _PD1 that is directly proportional to the light intensity of the beam applied to the light receiving surface 24 a to the phase acquisition unit 18 a of the modulation amount calculation unit 16 described later.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD2 that is directly proportional to the light intensity of the beam with which the light receiving surface 24b is irradiated.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD3 that is directly proportional to the light intensity of the beam with which the light receiving surface 24c is irradiated.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD4 that is directly proportional to the light intensity of the beam with which the light receiving surface 24d is irradiated.
In the first optical space communication device 1 shown in FIG. 9, the second photodiode 24 is realized by a quadrant photodiode. The second photodiode 24 is not limited to a four-division photodiode as long as it is a multi-division photodiode having a plurality of light receiving surfaces. Therefore, the second photodiode 24 may be realized by, for example, a two-divided photodiode or an eight-divided photodiode.

In the first optical space communication device 1 shown in FIG. 2, the first photodiode 14 outputs the current I _PD to the atmospheric structure constant calculation unit 15 and the phase acquisition unit 18, respectively. In the first optical space communication device 1, the first photodiode 14 outputs the current I _PD to only the atmospheric structure constant calculator 15.

The phase acquisition unit 18a is realized by, for example, the phase acquisition circuit 43 shown in FIG.
The phase acquisition unit 18a corresponds to the atmospheric structure constant Cn ² calculated by the atmospheric structure constant calculation unit 15 from the first table stored in the table storage unit 17, similarly to the phase acquisition unit 18 shown in FIG. The respective phases φ _m of the _M laser beams Lsr _{1 to} Lsr _{M being performed} are acquired as the first phase φ _1,m .
The phase acquisition unit 18a calculates an average value I _PDave of the currents I _{PD1 to} I _PD4 output from the second photodiode 24.
The phase acquisition unit 18a uses the second table stored in the table storage unit 17 to calculate the phase φ _m of each of the _M laser beams Lsr _{1 to} Lsr _M corresponding to the calculated average value I _PDave . 2 phase φ _2,m .
The phase acquisition unit 18 a outputs each of the _first phases φ _{1,1 to} φ _{1 ,M} and the second phases φ _{2,1 to} φ _2,M to the phase difference calculation unit 19.

In FIG. 9, each of the atmospheric structure constant calculation unit 15, the table storage unit 17, the phase acquisition unit 18a, and the phase difference calculation unit 19, which are some of the constituent elements of the laser light control device 3, are dedicated as shown in FIG. It is supposed to be realized by the hardware of. That is, it is assumed that the laser light control device 3 is realized by the atmospheric structure constant calculation circuit 41, the table storage circuit 42, the phase acquisition circuit 43, and the phase difference calculation circuit 44.

Some of the components of the laser light control device 3 are not limited to those realized by dedicated hardware, and some of the laser light control device 3 may be software, firmware, or a combination of software and firmware. May be realized by.
When a part of the laser light control device 3 is realized by software, firmware or the like, the table storage unit 17 is configured on the memory 51 of the computer. A program for causing a computer to execute the processing procedures of the atmospheric structure constant calculation unit 15, the phase acquisition unit 18a, and the phase difference calculation unit 19 is stored in the memory 51. Then, the processor 52 of the computer executes the program stored in the memory 51.

Next, the operation of the first optical space communication device 1 shown in FIG. 9 will be described. The operation of the second space optical communication apparatus 2 is the same as the operation of the first space optical communication apparatus 1, and the description thereof will be omitted.
Since the components other than the light intensity detection unit 21 and the phase acquisition unit 18a are the same as those of the first optical space communication device 1 shown in FIG. 2, only the operations of the light intensity detection unit 21 and the phase acquisition unit 18a will be described here. ..

When the beam splitter 22 of the light intensity detector 21 receives the beam from the receiver 11, the beam splitter 22 splits the beam into two, outputs one beam to the condenser lens 13 and outputs the other beam to the condenser lens 23. To do.
Upon receiving the beam from the beam splitting unit 22, the condenser lens 13 condenses the beam on the light receiving surface 14 a of the first photodiode 14.
The first photodiode 14 converts the beam condensed on the light receiving surface 14a by the condenser lens 13 into an electric signal.
The first photodiode 14 outputs, as an electric signal, a current I _PD that is directly proportional to the light intensity of the beam condensed on the light receiving surface 14 a to the atmospheric structure constant calculator 15.
Further, the first photodiode 14 outputs the current I _PD to a demodulator (not shown).

Upon receiving the beam from the beam splitting unit 22, the condenser lens 23 condenses the beam on the four light receiving surfaces 24a, 24b, 24c, 24d of the second photodiode 24.
The four light-receiving surfaces 24a, 24b, 24c, and 24d are uniformly irradiated with the beam condensed by the condensing lens 23, and are also condensed by the condensing lens 23 due to atmospheric fluctuations and the like. In some cases, the irradiated beam is not evenly irradiated.
FIG. 10A shows an example in which the four light-receiving surfaces 24a, 24b, 24c, and 24d are uniformly irradiated with the beam condensed by the condenser lens 23. FIG. 10B shows an example in which the four light-receiving surfaces 24a, 24b, 24c, and 24d are not uniformly irradiated with the beam condensed by the condenser lens 23.

When the beam emitted from the condenser lens 23 is applied to each of the four light receiving surfaces 24a, 24b, 24c, and 24d, the second photodiode 24 has four light receiving surfaces 24a, 24b, 24c, and 24d. The light intensity of the laser applied to each is detected.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD1 that is directly proportional to the light intensity of the beam with which the light receiving surface 24a is irradiated.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD2 that is directly proportional to the light intensity of the beam with which the light receiving surface 24b is irradiated.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD3 that is directly proportional to the light intensity of the beam with which the light receiving surface 24c is irradiated.
The second photodiode 24 outputs to the phase acquisition unit 18a a current I _PD4 that is directly proportional to the light intensity of the beam with which the light receiving surface 24d is irradiated.
The current I _PD and the currents I _{PD1 to} I _PD4 output from the first photodiode 14 change due to fluctuations in the atmosphere, but the average value I _PDave of the currents I _{PD1 to} I _PD4 is Even if fluctuations occur, it hardly changes.

When the phase acquisition unit 18a receives the atmospheric structure constant Cn ² from the atmospheric structure constant calculation unit 15, the phase acquisition unit 18a uses the first table stored in the table storage unit 17 to change the atmospheric structure constant Cn ² Each phase φ _m in the _M laser beams Lsr _{1 to} Lsr _M corresponding to the structural constant Cn ² is acquired as the first phase φ _1,m .
The phase acquisition unit 18 a outputs the acquired M first phases φ _{1,1 to} φ _{1 ,M} to the phase difference calculation unit 19.

位相取得部１８ａは、テーブル格納部１７に格納されている第２のテーブルから、算出した平均値Ｉ_{ＰＤａｖｅ}と対応しているＭ個のレーザ光Ｌｓｒ_１〜Ｌｓｒ_Ｍにおけるそれぞれの位相φ_ｍを第２の位相φ_２，ｍとして取得する。
具体的には、位相取得部１８ａは、第２のテーブルに格納されている電流Ｉ_ＰＤ１〜Ｉ_ＰＤＫの中で、平均値Ｉ_{ＰＤａｖｅ}と最も近い電流を特定する。
位相取得部１８ａは、第２のテーブルから、特定した電流と対応しているＭ個のレーザ光Ｌｓｒ_１〜Ｌｓｒ_Ｍにおけるそれぞれの位相φ_ｍを第２の位相φ_２，ｍとして取得する。
例えば、特定した電流が、電流Ｉ_ＰＤ２であれば、位相取得部１８ａは、第２の位相φ_２，１〜φ_２，Ｍとして、θ_２５，θ_２５，θ_２７，・・・，θ_２８を取得する。
位相取得部１８ａは、取得したＭ個の第２の位相φ_２，１〜φ_２，Ｍを位相差算出部１９に出力する。Upon receiving the currents I _{PD1 to} I _PD4 from the second photodiode 24, the phase acquisition unit 18 a calculates the average value I _PDave of the currents I _{PD1 to} I _PD4 as shown in the following equation (7).

The phase acquisition unit 18a uses the second table stored in the table storage unit 17 to calculate the phase φ _m of each of the _M laser beams Lsr _{1 to} Lsr _M corresponding to the calculated average value I _PDave . 2 phase φ _2,m .
Specifically, the phase acquisition unit 18a identifies the current closest to the average value I _PDave among the currents I _{PD1 to} I _PDK stored in the second table.
The phase acquisition unit 18a acquires, from the second table, the respective phases φ _m in the _M laser beams Lsr _{1 to} Lsr _M corresponding to the specified current as the second phases φ _2,m .
For example, if the identified current is the current I _PD2 , the phase acquisition unit 18a sets θ ₂₅ , θ ₂₅ , θ ₂₇ ,..., θ ₂₈ as the _second phases φ _{2,1 to} φ _2,M. To get
The phase acquisition unit 18 a outputs the acquired M second phases φ _{2,1 to} φ _2,M to the phase difference calculation unit 19.

In the second embodiment described above, the light intensity detector 21 has the first photodiode 14 that detects the light intensity of the beam received by the receiver 11 and the plurality of light receiving surfaces 24a, 24b, 24c, 24d. Of the beams received by the receiving unit 11, the second photodiode 24 for detecting the light intensity of the beam applied to each of the light receiving surfaces 24a, 24b, 24c, 24d is provided, and the atmospheric structure is provided. The constant calculation unit 15 calculates the atmospheric structure constant from the light intensity detected by the first photodiode 14, and the phase acquisition unit 18a calculates the average value of the light intensity detected by the second photodiode 24, respectively. Then, the laser light control device 3 is configured so as to obtain the respective second phases corresponding to the average values from the second table. Therefore, the laser light control device 3 can reduce the fluctuation of the light intensity of the beam in a shorter time than the control by mechanical driving, and even if the fluctuation of the atmosphere occurs, the second phase False acquisition can be prevented.

In the laser beam control device 3 shown in FIG. 9, the phase acquisition unit 18a identifies the current closest to the average value I _PDave among the currents I _{PD1 to} I _PDK stored in the second table, and the second From the table, the respective phases φ _m in the _M laser beams Lsr _{1 to} Lsr _M corresponding to the specified current are acquired as the second phases φ _2,m .
However, this is merely an example, and the phase acquisition unit 18a may acquire the second phase φ _2,m as follows.

Phase acquisition unit 18a, calculating the average value _{I PDave,} as shown in the following equation (8), the current _I PD1 _{~I PDK} stored in the second table, the difference ΔI between the average value _{I PDave PD1 to} ΔI _PDK are calculated respectively.

位相取得部１８ａは、第２のテーブルに格納されている電流Ｉ_ＰＤ１〜Ｉ_ＰＤＫの中で、加算結果Ｉ_ｔｒｕｅと一致する電流を特定する。
位相取得部１８ａは、第２のテーブルから、加算結果Ｉ_ｔｒｕｅと一致する電流と対応しているＭ個のレーザ光Ｌｓｒ_１〜Ｌｓｒ_Ｍにおけるそれぞれの位相φ_ｍを第２の位相φ_２，ｍとして取得する。
位相取得部１８ａは、取得したＭ個の第２の位相φ_２，１〜φ_２，Ｍを位相差算出部１９に出力する。The phase acquisition unit 18a identifies the smallest difference ΔI _PDmin among the calculated differences ΔI _{PD1 to} ΔI _PDK .
The phase acquisition unit 18a adds the _specified difference ΔI _PDmin and the average value I _PDave to obtain the addition result I _true of the difference ΔI _PDmin and the average value I _PDave , as shown in the following expression (9).

The phase acquisition unit 18a identifies a current that matches the addition result I _true among the currents I _{PD1 to} I _PDK stored in the second table.
From the second table, the phase acquisition unit 18a outputs the respective phases φ _m in the _M laser beams Lsr _{1 to} Lsr _M corresponding to the currents that match the addition result I _true to the second phases φ _2,m. To get as.
The phase acquisition unit 18 a outputs the acquired M second phases φ _{2,1 to} φ _2,M to the phase difference calculation unit 19.

It should be noted that, within the scope of the invention, the invention of the present application is capable of freely combining the respective embodiments, modifying any constituent element of each embodiment, or omitting any constituent element in each embodiment. ..

The present invention is suitable for a laser light control device that modulates the phase of laser light, an optical space communication device, and an optical space communication system.

DESCRIPTION OF SYMBOLS 1 1st optical space communication apparatus, 2 2nd optical space communication apparatus, 3 laser light control apparatus, 10 receiver, 11 receiving part, 12 light intensity detection part, 13 condensing lens, 14 1st photodiode, 14a Light receiving surface, 15 Atmospheric structure constant calculation unit, 16 Modulation amount calculation unit, 17 Table storage unit, 18, 18a Phase acquisition unit, 19 Phase difference calculation unit, 21 Light intensity detection unit, 22 Beam splitting unit, 23 Condenser lens , 24 second photodiode, 24a, 24b, 24c, 24d light receiving surface, 30 transmitter, 31 power supply, 32 reference laser, 33 beam splitter, 34 phase modulator, 34-1 to 34-M optical phase modulator , 35 transmitter, 36 optical amplifier, 36-1 to 36-M optical amplifier, 37 beam combiner, 38 beam transmitter, 41 atmospheric structure constant calculation circuit, 42 table storage circuit, 43 phase acquisition circuit, 44 phase difference Calculation circuit, 51 memory, 52 processor.

Claims (7)

When the beam transmitted from the optical space communication device of the communication partner is received, a light intensity detection unit that detects the light intensity of the beam,
Each time the light intensity is detected by the light intensity detection unit, the light intensity is acquired, and from the plurality of acquired light intensities, the degree of disorder of the refractive index of the atmosphere between the optical space communication device of the communication partner is disturbed. An atmospheric structure constant calculation unit for calculating the atmospheric structure constants shown,
Based on the atmospheric structure constant calculated by the atmospheric structure constant calculation unit, a modulation amount calculation unit for calculating the modulation amount of each phase of a plurality of laser light is a beam of the beam to be transmitted is divided,
A laser light control device comprising: a phase modulation unit that modulates the phase of each laser light according to each modulation amount calculated by the modulation amount calculation unit. The modulation amount calculation unit,
A first table showing the correspondence between the atmospheric structure constants and the phases of the respective laser lights, and a second table showing the correspondence between the light intensity of the beam and the phases of the respective laser lights are stored. Table storage,
From the first table, the phase of each laser beam corresponding to the atmospheric structure constant calculated by the atmospheric structure constant calculating unit is acquired as the first phase, and from the second table, the light intensity is obtained. A phase acquisition unit that acquires, as the second phase, the phase of each laser beam corresponding to the light intensity detected by the detection unit;
A phase difference for calculating a phase difference between each first phase acquired by the phase acquisition unit and each second phase acquired by the phase acquisition unit as a modulation amount of the phase of each laser beam. The laser light control device according to claim 1, further comprising a calculation unit. The light intensity detection unit,
A first photodiode for detecting the light intensity of the received beam;
A second photodiode having a plurality of light-receiving surfaces, each of which has a second photodiode that detects the light intensity of each of the beams received by the light-receiving surface,
The atmospheric structure constant calculation unit, each time the light intensity is detected by the first photodiode , acquires the light intensity, and calculates the atmospheric structure constant from the plurality of acquired light intensity,
The phase acquisition unit calculates an average value of the light intensity detected by each of the second photodiodes, and acquires each second phase corresponding to the average value from the second table. The laser light control device according to claim 2, wherein A receiving unit that receives a beam transmitted from an optical space communication device of a communication partner,
A light intensity detector for detecting the light intensity of the beam received by the receiver,
Each time the light intensity is detected by the light intensity detection unit, the light intensity is acquired, and from the plurality of acquired light intensities, the degree of disorder of the refractive index of the atmosphere between the optical space communication device of the communication partner is disturbed. An atmospheric structure constant calculation unit for calculating the atmospheric structure constants shown,
A beam splitting unit that splits a beam to be transmitted and outputs a plurality of laser lights that are split lights,
Based on the atmospheric structure constant calculated by the atmospheric structure constant calculation unit, a modulation amount calculation unit for calculating the modulation amount of the phase of each laser light output from the beam splitting unit,
According to each modulation amount calculated by the modulation amount calculation unit, a phase modulation unit that modulates the phase of each laser light,
An optical space communication device, comprising: a transmission unit that generates a beam from a plurality of laser lights whose phases are modulated by the phase modulation unit and that transmits the generated beam to the optical space communication device of the communication partner. The modulation amount calculation unit,
A first table showing the correspondence between the atmospheric structure constants and the phases of the respective laser lights, and a second table showing the correspondence between the light intensity of the beam and the phases of the respective laser lights are stored. Table storage,
From the first table, the phase of each laser beam corresponding to the atmospheric structure constant calculated by the atmospheric structure constant calculating unit is acquired as the first phase, and from the second table, the light intensity is obtained. A phase acquisition unit that acquires, as the second phase, the phase of each laser beam corresponding to the light intensity detected by the detection unit;
A phase difference for calculating a phase difference between each first phase acquired by the phase acquisition unit and each second phase acquired by the phase acquisition unit as a modulation amount of the phase of each laser beam. The optical space communication device according to claim 4, further comprising a calculation unit. The light intensity detection unit,
A first photodiode for detecting the light intensity of the beam received by the receiver,
A second photodiode having a plurality of light-receiving surfaces, each of which detects the light intensity of the beam irradiated to each light-receiving surface among the beams received by the receiving unit,
The atmospheric structure constant calculation unit, each time the light intensity is detected by the first photodiode , acquires the light intensity, and calculates the atmospheric structure constant from the plurality of acquired light intensity,
The phase acquisition unit calculates an average value of the light intensity detected by each of the second photodiodes, and acquires each second phase corresponding to the average value from the second table. The optical space communication device according to claim 5, wherein A first optical space communication device and a second optical space communication device,
The first optical space communication device is an optical space communication device with which the second optical space communication device is a communication partner,
The second optical space communication device is an optical space communication device with which the first optical space communication device is a communication partner,
Each of the first optical space communication device and the second optical space communication device,
A receiving unit that receives a beam transmitted from an optical space communication device of a communication partner,
A light intensity detector for detecting the light intensity of the beam received by the receiver,
Every time the light intensity is detected by the light intensity detection unit, the light intensity is acquired, and the plurality of acquired light intensities are used to determine the difference between the first optical space communication device and the second optical space communication device. An atmospheric structure constant calculation unit that calculates an atmospheric structure constant indicating the degree of turbulence of the refractive index of the atmosphere,
A beam splitting unit that splits a beam to be transmitted and outputs a plurality of laser lights that are split lights,
Based on the atmospheric structure constant calculated by the atmospheric structure constant calculation unit, a modulation amount calculation unit for calculating the modulation amount of the phase of each laser light output from the beam splitter,
According to each modulation amount calculated by the modulation amount calculation unit, a phase modulation unit that modulates the phase of each laser light,
An optical space communication system, comprising: a transmission unit that generates a beam from a plurality of laser lights whose phases are modulated by the phase modulation unit and transmits the generated beam to an optical space communication device of a communication partner. ..

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