Optical communication devices, artificial satellites, optical communication methods, programs

Abstract

The present invention provides an optical communication device that prevents the balance of output power for each wavelength included in an optical signal from being disrupted even when the output power of the optical signal is changed. [Solution] The spatial distance to the other party's communication device located at a distance in space is obtained. The gain of an optical signal containing multiple wavelengths is adjusted using at least two optical amplification means. The gain of the optical signal in at least two optical amplification means is controlled to match the output power of each wavelength. The attenuation of the optical signal is adjusted between the two optical amplification means based on the spatial distance.

Description

Technical Field

[0001] The present disclosure relates to an optical communication device, a satellite, an optical communication method, and a program.

Background Art

[0002] When communicating with a plurality of counterparts using an optical signal, it is necessary to change the output power of the optical signal according to the communication distance.

[0003] Related techniques are disclosed in Patent Document 1. Patent Document 1 discloses a technique of an optical amplification device that can amplify an optical signal to an appropriate intensity even when the number of multiplexed optical signals varies.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technique of communicating with a counterpart using an optical signal as described above, the optical signal may be a multiplexed optical signal of a plurality of wavelengths. Here, in the method of adjusting the gain of an optical amplifier to change the output power of the optical signal, the gain characteristics of each wavelength in the optical signal change, so the balance of the output power of each wavelength may be lost.

[0006] An object of the present disclosure is to provide an optical communication device, a satellite, an optical communication method, and a program that solve the above problems.

Means for Solving the Problems

[0007] An optical communication device according to one aspect of the present disclosure includes: distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space; at least two optical amplification means for adjusting the gain of an optical signal including multiple wavelengths; gain control means corresponding to the at least two optical amplification means for controlling the gain of the optical signal to match the output power of each wavelength; and attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance.

[0008] An artificial satellite according to one aspect of the present disclosure includes distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space; at least two optical amplification means for adjusting the gain of an optical signal including multiple wavelengths; gain control means corresponding to the at least two optical amplification means for controlling the gain of the optical signal to match the output power of each wavelength; and attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance.

[0009] An optical communication method according to one aspect of the present disclosure acquires a spatial distance to a communication device of another party located at a distance in space, adjusts the gain of an optical signal including multiple wavelengths using at least two optical amplification means, controls the gain of the optical signal in the at least two optical amplification means to match the output power of each wavelength, and adjusts the attenuation of the optical signal between the two optical amplification means based on the spatial distance.

[0010] A program according to one aspect of the present disclosure causes a computer for an optical communication device, which includes distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space, and at least two optical amplification means for adjusting the gain of an optical signal including multiple wavelengths, to function as gain control means corresponding to the at least two optical amplification means for controlling the gain of the optical signal to match the output power of each wavelength, and attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance. [Effects of the Invention]

[0011] According to the above embodiment, even if the output power of the optical signal is changed, it is possible to prevent the balance of the output power of each wavelength included in the optical signal from being disrupted. [Brief explanation of the drawing]

[0012] [Figure 1] This is a functional block diagram of the optical communication device as disclosed herein. [Figure 2] This figure shows the mode of optical communication in multiple artificial satellites equipped with the optical communication devices described in this disclosure. [Figure 3] This diagram shows the output power at each wavelength when related optical communication devices communicate with the other party's optical communication device. [Figure 4] This diagram shows the processing flow of the optical communication device disclosed herein. [Figure 5] This disclosure shows the output power of each wavelength included in the optical signal output by the control of the optical communication device. [Figure 6] This figure shows another configuration of the optical communication device disclosed herein. [Figure 7] This figure shows other processing flows of the optical communication device disclosed herein. [Figure 8] This figure shows the hardware configuration of an optical communication device according to one aspect of the present disclosure. [Modes for carrying out the invention]

[0013] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a functional block diagram of the optical communication device disclosed herein. As shown in the figure, the optical communication device 1 of this disclosure performs the functions of a first transmitting unit 11, a second transmitting unit 12, a multiplexing unit 13, a first optical amplification unit 14, an attenuator 15, a second optical amplification unit 16, a first gain control unit 17, a second gain control unit 18, an intensity control unit 19, and an output monitor 100. The optical communication device 1 communicates with a distance measuring unit 2 that measures the spatial distance to another optical communication device 1 located at a distance in space. The distance measuring unit 2 may be included as part of the configuration of the optical communication device 1.

[0014] The first transmitting unit 11 transmits an optical signal of wavelength a. The second transmission unit 12 transmits an optical signal with wavelength b. The multiplexing unit 13 multiplexes the input optical signals with a plurality of wavelengths. The first optical amplification unit 14 amplifies the optical signal output from the multiplexing unit 13. The attenuator 15 adjusts the attenuation amount of the optical signal. The second signal amplification unit 16 amplifies the optical signal output from the attenuator 15. The first gain control unit 17 adjusts the gain of the first optical amplification unit 14. The second gain control unit 18 adjusts the gain of the second optical amplification unit 16. The intensity control unit 19 adjusts the attenuation amount of the optical signal in the attenuator 15. The output monitor 100 monitors the output power output from the second optical amplification unit.

[0015] In the optical communication device 1 shown in FIG. 1, the intensity control unit 19, which is distance acquisition means, acquires the spatial distance from a communication device of a counterpart located apart in space. The first optical amplification unit 14 and the second optical amplification unit 16, which are optical amplification means, adjust the gain of an optical signal including a plurality of wavelengths. The first gain control unit 17, which is gain control means, controls the gain of the optical signal in the first optical amplifier 14, and the second gain control unit 18, which is another gain control means, controls the gain of the optical signal in the second optical amplifier 16 to make the output power of each wavelength coincide. The attenuator 15, which is attenuation means, adjusts the attenuation amount of the optical signal between the first optical amplification unit 14 and the second optical amplification unit 16 based on the spatial distance.

[0016] FIG. 2 is a diagram showing an optical communication mode in a plurality of artificial satellites on which the optical communication device is mounted. Figure 2 shows artificial satellites 21, 22, and 23. For example, it is assumed that artificial satellite 21 communicates with artificial satellites 22 and 23 via optical communication. As an example, the communication distance (spatial distance) between artificial satellite 21 and artificial satellite 22 is longer than a threshold, and the output power of the optical signal transmitted by artificial satellite 21 needs to be high. On the other hand, the communication distance between artificial satellite 21 and artificial satellite 23 is shorter than the communication distance between artificial satellite 21 and artificial satellite 22, and the output power of the optical signal when artificial satellite 21 and artificial satellite 23 communicate can be lower than the output power of the optical signal when artificial satellite 21 and artificial satellite 22 communicate.

[0017] In recent years, the demand for high-capacity communication has increased due to the growing data volume from communication and observation satellites. Optical communication devices are being installed on satellites because they offer not only higher capacity than radio waves but also advantages in terms of being license-free (no application is required for the use of radio frequency bands) and highly energy-efficient. Furthermore, by combining optical communication satellites with satellite constellations, which build communication networks in orbit by communicating with each other, a high-capacity and highly connected communication network can be realized. To further increase capacity, the application of wavelength division multiplexing in orbit is necessary. However, in satellite constellations, it is necessary to communicate between satellites at different communication distances in the event of a failure of an adjacent satellite or when communicating with other orbital planes. Therefore, a transmitter is needed that outputs appropriate output power according to the communication distance while maintaining the power ratio of each wavelength in an optical signal containing light of multiple wavelengths.

[0018] Figure 3 shows the output power at each wavelength when related optical communication devices communicate with the other party's optical communication device. In related technologies, as shown in Figure 3, when an optical signal containing multiple wavelengths, such as wavelength a and wavelength b, is amplified by gain control, the optical output power for each wavelength differs. More specifically, when amplifying an optical signal containing multiple wavelengths, increasing the excitation light of the optical amplifier to increase the gain changes the gain spectrum of the optical amplifier, which in turn changes the gain at each wavelength, resulting in different output power ratios for each wavelength.

[0019] To address these challenges, the optical communication device 1 of this disclosure has the configuration shown in Figure 1. The processing of the optical communication device 1 of this disclosure will be described in detail below.

[0020] Figure 4 shows the processing flow of the optical communication device disclosed herein. Figure 5 shows the output power of each wavelength included in the optical signal output by the control of the optical communication device in this disclosure.

[0021] First, the first transmitter 11 outputs an optical signal of wavelength a (step S101). The second transmitter 12 outputs an optical signal of wavelength b (step S102). The first transmitter 11 and the second transmitter 12 modulate the signal light of each wavelength to add the data to be transmitted to the signal light. The optical signals of wavelength a and wavelength b are input to the multiplexer 13. The multiplexer 13 combines the optical signals of wavelength a and wavelength b and outputs it to the first optical amplifier 14 (step S103). The multiplexer 13 may use the AWG (Arrayed Waveguide Grating) method, where the focusing angle differs for each wavelength, to combine the light of each wavelength into a single fiber. Note that there may be three or more wavelengths corresponding to each signal that is superimposed on the optical signal.

[0022] The first optical amplifier 14 amplifies the optical signal based on a predetermined initial gain control signal obtained from the first gain control unit 17 and outputs the optical signal to the attenuator 15 (step S104).

[0023] The attenuator 15 adjusts the amount of attenuation of the input optical signal based on an initial attenuation signal obtained from a predetermined intensity control unit 19 and outputs it (step S105).

[0024] The second optical amplifier 16 receives an optical signal from the attenuator 15 and amplifies the optical signal based on a predetermined initial gain control signal obtained from the second gain control unit 18, and outputs it (step S106).

[0025] At this stage, the gain control signal output by the first gain control unit 17 to the first optical amplifier 14 and the gain control signal output by the second gain control unit 18 to the second amplifier 16 are used to pre-control the output power of wavelengths a and b in the optical signal output by the second optical amplifier 16 so that they are equal, as shown in (41) of Figure 5. Specifically, before the optical communication device 1 is mounted on the satellite, the values ​​of the gain control signals of the first gain control unit 17 and the second gain control unit 18 are adjusted in advance so that the output power of wavelengths a and b in the optical signal output by the second optical amplifier 16 is equal. By adjusting the values ​​of the gain control signals of the first gain control unit 17 and the second gain control unit 18, the gains in each optical amplifier can be changed to make the output power of wavelengths a and b in the optical signal output by the second optical amplifier 16 equal.

[0026] The distance measurement unit 2 measures the distance to the optical communication device 2 that will be the communication partner (step S107). For example, if optical communication device 1 is included in artificial satellites 21, 22, or 23, the distance information to the communication partner artificial satellite included in the signal received from the ground station may be used. Alternatively, the distance measurement unit 2 may calculate the distance from the speed of light and the timing of the transmission and reception of optical signals between artificial satellites. The distance measurement unit 2 outputs the communication distance (spatial distance) to the communication partner to the intensity control unit 19. The optical communication device 2 that will be the communication partner may receive its coordinates from the ground station.

[0027] The intensity control unit 19 determines the amount of attenuation corresponding to the communication distance (step S108). For example, the intensity control unit 19 may calculate the amount of attenuation by inputting the communication distance into a predetermined attenuation calculation formula. Alternatively, the intensity control unit 19 may calculate the amount of attenuation corresponding to the acquired communication distance by interpolation calculation based on the relationship between communication distance and attenuation recorded in the data table. Alternatively, the intensity control unit 19 may read the amount of attenuation corresponding to the acquired communication distance based on the relationship between communication distance and attenuation recorded in the data table.

[0028] The intensity control unit 19 outputs a control signal including the specified attenuation amount to the attenuator 15. The attenuator 15 attenuates the optical signal output from the first optical amplifier 14 based on the attenuation amount included in the control signal and outputs it to the second optical amplifier 16 (step S109). As a result, the output power of the optical signal output from the second optical amplifier 16 becomes the output power corresponding to the communication distance with the other party. Note that if the attenuation amount of the attenuator 15 is increased, the output power of the optical signal decreases, and if the attenuation amount is decreased, the output power of the optical signal increases.

[0029] When the attenuation amount of the attenuator 15 is controlled according to the communication distance with the other party, the gains of the first optical amplifier 14 and the second optical amplifier 16 are controlled by the first gain control unit 17 and the second gain control unit 18 in the same way as before the attenuation amount of the attenuator 15 was changed. At this time, the balance of the output power of each wavelength included in the optical signal based on gain control (the power ratio of each wavelength) does not change, and only the absolute value of the output power of each wavelength included in the optical signal changes. Therefore, as shown in (42) of Figure 5, even after adjusting the attenuation amount, the output power ratio of each wavelength remains constant, and the output power of each wavelength can be increased or decreased according to the communication distance with the other party.

[0030] According to the processing of the optical communication device 1 described above, even if the output power of the optical signal is changed, it is possible to prevent the balance of the output power ratio of each wavelength included in the optical signal from being disrupted.

[0031] Figure 6 shows the various configurations of an optical communication device. Figure 7 shows other processing flows for optical communication devices. The optical communication device 1 may include a distance acquisition means 61, an optical amplification means 62, a gain control means 63, and an attenuation means 64. The distance acquisition means 61 acquires the spatial distance to the other party's communication device, which is located at a distance in space. The optical amplification means 62 adjusts the gain of an optical signal containing multiple wavelengths using at least two optical amplification means. The gain control means 63 controls the gain of the optical signal in at least two optical amplification means to match the output power of each wavelength. The attenuation means 64 adjusts the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance.

[0032] Figure 8 shows the hardware configuration of an optical communication device according to one aspect of the present disclosure. As shown in Figure 8, the optical communication device 1 may perform its functions by having a CPU (Central Processing Unit) 101 execute a program in some of its processing units (means). In this case, the optical communication device 1 may have a computer internally implemented, which includes a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a storage device 104, a communication module 105, an input device 106, etc.

[0033] Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to the embodiments described above. Various modifications to the structure and details of the present disclosure may be made that can be understood by those skilled in the art within the scope of the present disclosure.

[0034] Some or all of the above embodiments may also be described as follows, but are not limited to the following:

[0035] (Note 1) Distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space, At least two optical amplification means for adjusting the gain of an optical signal containing multiple wavelengths, Gain control means corresponding to the at least two optical amplification means that control the gain of the optical signal to match the output power of each wavelength, An attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance, An optical communication device equipped with [the necessary components].

[0036] (Note 2) The optical amplification means comprises a first optical amplification means and a second optical amplification means, The attenuation means adjusts the amount of attenuation of the optical signal output from the first optical amplification means to the second optical amplification means. The optical communication device described in Appendix 1.

[0037] (Note 3) The gain control means includes a first gain control means for adjusting the gain of the first optical amplification means and a second gain control means for adjusting the gain of the second optical amplification means. Optical communication device as described in Appendix 2.

[0038] (Note 4) Distance measuring means for measuring the spatial distance to a communication device of another party located at a distance in space, An optical communication device as described in Appendix 3, which includes the following features.

[0039] (Note 5) The aforementioned communication device of the other party is an optical communication device as described in Appendix 4, which is a plurality of mobile bodies moving in outer space.

[0040] (Note 6) The optical communication device described in Appendix 5, which includes a signal that is superimposed on two or more wavelengths in the aforementioned optical signal.

[0041] (Note 7) An optical communication device as described in Appendix 6, installed on a mobile vehicle traveling through outer space.

[0042] (Note 8) An artificial satellite equipped with an optical communication device as described in any one of the items from Appendix 1 to Appendix 7.

[0043] (Note 9) Obtain the spatial distance to the other party's communication device, which is located at a distance in space. The gain of an optical signal containing multiple wavelengths is adjusted by at least two optical amplification means. The gain of the optical signal in the at least two optical amplification means is controlled to match the output power of each wavelength. The amount of attenuation of the optical signal is adjusted between the two optical amplification means based on the spatial distance. Optical communication method.

[0044] (Note 10) The optical amplification means comprises a first optical amplification means and a second optical amplification means. Adjusts the amount of attenuation of the optical signal output from the first optical amplification means to the second optical amplification means. The optical communication method described in Appendix 9.

[0045] (Note 11) The gain of the first optical amplification means is adjusted by the first gain control means, and the gain of the second optical amplification means is adjusted by the second gain control means. The optical communication method described in Appendix 10.

[0046] (Note 12) Measure the spatial distance to a communication device located at a distance in space. The optical communication method described in Appendix 11.

[0047] (Note 13) The optical communication method described in Appendix 12, wherein the other party's communication device is a plurality of moving objects moving in outer space.

[0048] (Note 14) The optical communication method described in Appendix 13, which includes a signal carried on two or more wavelengths in addition to the aforementioned optical signal.

[0049] (Note 15) Distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space, A computer for an optical communication device, comprising at least two optical amplification means for adjusting the gain of an optical signal containing multiple wavelengths, Gain control means corresponding to the at least two optical amplification means that control the gain of the optical signal to match the output power of each wavelength, An attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance, A program that makes it function as such.

[0050] (Note 16) The computer of the optical communication device comprises a first optical amplification means and a second optical amplification means as the optical amplification means, The attenuation means adjusts the amount of attenuation of the optical signal output from the first optical amplification means to the second optical amplification means. The program described in Appendix 15.

[0051] (Note 17) The gain control means is configured to function as a first gain control means for adjusting the gain of the first optical amplification means and a second gain control means for adjusting the gain of the second optical amplification means. The program described in Appendix 16.

[0052] (Note 18) It functions as a distance measuring device to measure the spatial distance to a communication device of another party located at a distance in space. The program described in Appendix 17. [Explanation of Symbols]

[0053] 1. Optical communication device 2. Distance measurement unit 11. First transmission section 12. Second transmission section 13. Combined wave section 14. First optical amplification unit (optical amplification means 62) 15. Attenuator (attenuation means 64) 16. Second optical amplification unit (optical amplification means 62) 17. First gain control unit (gain control means 63) 18. Second gain control unit (gain control means 63) 19. Strength control unit (distance acquisition means 61) 100... Output Monitor 21,22,23...Artificial satellite

Claims

1. Distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space, At least two optical amplification means for adjusting the gain of an optical signal containing multiple wavelengths, Gain control means corresponding to the at least two optical amplification means that control the gain of the optical signal to match the output power of each wavelength, An attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance, An optical communication device equipped with [the necessary components].

2. The optical amplification means comprises a first optical amplification means and a second optical amplification means, The attenuation means adjusts the amount of attenuation of the optical signal output from the first optical amplification means to the second optical amplification means. The optical communication device according to claim 1.

3. The gain control means includes a first gain control means for adjusting the gain of the first optical amplification means and a second gain control means for adjusting the gain of the second optical amplification means. The optical communication device according to claim 2.

4. Distance measuring means for measuring the spatial distance to a communication device of another party located at a distance in space, The optical communication device according to claim 3, comprising:

5. The optical communication device according to claim 4, wherein the other party's communication device is a plurality of moving bodies moving in outer space.

6. The optical communication device according to claim 5, which includes a signal that is superimposed on two or more wavelengths in the optical signal.

7. An optical communication device according to claim 6, provided on a mobile body moving in outer space.

8. An artificial satellite equipped with an optical communication device according to any one of claims 1 to 7.

9. Obtain the spatial distance to the other party's communication device, which is located at a distance in space. The gain of an optical signal containing multiple wavelengths is adjusted using at least two optical amplification means. The gain of the optical signal in the at least two optical amplification means is controlled to match the output power of each wavelength. The attenuation of the optical signal is adjusted between the two optical amplification means based on the spatial distance. Optical communication method.

10. Distance acquisition means for acquiring the spatial distance to a communication device of another party located at a distance in space, A computer for an optical communication device, comprising at least two optical amplification means for adjusting the gain of an optical signal containing multiple wavelengths, Gain control means corresponding to the at least two optical amplification means that control the gain of the optical signal to match the output power of each wavelength, An attenuation means for adjusting the amount of attenuation of the optical signal between the two optical amplification means based on the spatial distance, A program that makes it function as such.

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