Optical spatial communication device, optical spatial communication system, and optical spatial communication method

Abstract

To provide an optical space communication device with more efficient optical axis alignment.SOLUTION: An optical space communication device (1) includes a plurality of light transmitting units (10) and an optical axis alignment unit (20) that aligns the optical axis of each of the plurality of light transmitting units (10) for each of a plurality of light receiving units (130) provided in a communication partner. The optical axis alignment unit (20) causes at least one of the plurality of light transmitting units (10) to emit scanning light (3) while changing its direction, and based on the emission direction of the scanning light (3) emitted from the light transmitting unit (10) and received by the corresponding light receiving unit (130), aligns the optical axis of a light transmitting unit (10) different from the light transmitting unit (10).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical space communication apparatus, an optical space communication system, and an optical space communication method. [Background Art]

[0002] In a technology for performing optical communication by transmitting and receiving a directional optical communication medium, it is necessary to align the communication direction (optical axis) by making the light transmitting side and the light receiving side face each other. For aligning the optical axis (aligning the optical axes), for example, Patent Document 1 discloses that searching is performed by adjusting the orientation of a stage to which a communication light emitting unit, a searching light emitting unit, and a light receiving unit of a master device, which is the light transmitting side, are fixed, such that the optical axis of the master device faces the direction of a slave device.

[0003] Also in a communication apparatus that realizes spatial multiplexing transmission through simultaneous connection of a plurality of beams, it is necessary to align the optical axis. For example, Patent Document 2 discloses an optical space communication apparatus including a mount provided with a mechanism for angularly adjusting, vertically and horizontally, a unit configured to include a plurality of light transmitting system or light receiving system modules. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 09-107330 [Patent Document 2] Japanese Unexamined Patent Publication No. 02-237329 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In an optical space communication apparatus that performs spatial multiplexing transmission, it takes time when attempting to individually perform optical axis alignment for a plurality of light transmitting systems. Therefore, development of a technology for efficiently performing optical axis alignment for a plurality of light transmitting systems is demanded.

[0006] Therefore, one aspect of the present invention has been made in view of the above problems, and one example of its objective is to provide a technique for efficiently aligning the optical axes of multiple light transmitting systems in an optical spatial communication device that performs spatial multiplexing. [Means for solving the problem]

[0007] An optical space communication device according to one aspect of the present invention comprises a plurality of light transmitting means and an optical axis alignment means for aligning the optical axis of each of the plurality of light transmitting means with respect to each of a plurality of light receiving means provided by the communication partner of the optical space communication device, wherein the optical axis alignment means causes at least one of the plurality of light transmitting means to transmit scanning light while changing direction, and aligns the optical axis of a light transmitting means different from the at least one light transmitting means based on the transmission direction of the scanning light transmitted from the at least one light transmitting means and received by the corresponding light receiving means.

[0008] An optical space communication system according to one aspect of the present invention includes a plurality of optical space communication devices, where at least one of the plurality of optical space communication devices includes a plurality of light transmitting means and an optical axis alignment means for aligning the optical axis of each of the plurality of light transmitting means with respect to each of a plurality of light receiving means provided by the optical space communication device that is the communication partner, wherein the optical axis alignment means causes at least one of the plurality of light transmitting means to transmit scanning light while changing direction, and aligns the optical axis of a light transmitting means different from the at least one light transmitting means based on the transmission direction of the scanning light transmitted from the at least one light transmitting means and received by the corresponding light receiving means.

[0009] An optical space communication method according to one aspect of the present invention is an optical space communication method between a first optical space communication device equipped with a plurality of light transmitting means and a second optical space communication device equipped with a plurality of light receiving means, which is a communication partner of the first optical space communication device, and includes aligning the optical axis of each of the plurality of light transmitting means with respect to each of the plurality of light receiving means, wherein aligning the optical axis includes causing at least one of the plurality of light transmitting means to transmit scanning light while changing direction, and aligning the optical axis of a light transmitting means different from the at least one light transmitting means based on the transmission direction of the scanning light transmitted from the at least one light transmitting means and received by the corresponding light receiving means.

[0010] One aspect of the present invention includes a program for operating a computer as the optical space communication device. [Effects of the Invention]

[0011] According to one aspect of the present invention, it is possible to provide an optical spatial communication device, an optical spatial communication system, and an optical spatial communication method that improve the efficiency of optical axis alignment. [Brief explanation of the drawing]

[0012] [Figure 1] This is a block diagram showing the configuration of an optical space communication system comprising an optical space communication device according to an exemplary embodiment 1 of the present invention. [Figure 2] This figure illustrates the processing flow of an optical spatial communication method according to an exemplary embodiment 1 of the present invention. [Figure 3] This is a block diagram showing the configuration of an optical space communication system comprising an optical space communication device according to an exemplary embodiment 2 of the present invention. [Figure 4] This figure shows the configuration of the light transmitting unit of an optical space communication device according to exemplary embodiment 2 of the present invention. [Figure 5] This figure shows the configuration of the light receiving unit of an optical space communication device according to exemplary embodiment 2 of the present invention. [Figure 6] This figure shows the arrangement configuration of multiple light transmitting units in an optical space communication device according to exemplary embodiment 2 of the present invention. [Figure 7] It is a diagram showing another example of the arrangement configuration of a plurality of light transmitting units of the optical space communication device according to exemplary embodiment 2 of the present invention. [Figure 8] It is a diagram explaining details of the optical space communication device according to exemplary embodiment 2 of the present invention. [Figure 9] It is a diagram showing the arrangement configuration of light transmitting units that output scanning light among the plurality of light transmitting units of the optical space communication device according to exemplary embodiment 2 of the present invention. [Figure 10] It is a block diagram showing the configuration of an optical space communication system including the optical space communication device according to exemplary embodiment 3 of the present invention. [Figure 11] It is a diagram explaining the processing flow of the optical space communication method according to exemplary embodiment 3 of the present invention. [Figure 12] It is a block diagram showing the configuration of an optical space communication system including the optical space communication device according to exemplary embodiment 4 of the present invention. [Figure 13] It is a block diagram showing the hardware configuration of a computer which is an implementation example of the optical space communication device according to each exemplary embodiment of the present invention. DETAILED DESCRIPTION OF EMBODIMENTS

[0013] [Exemplary Embodiment 1] A first exemplary embodiment of the present invention will be described in detail with reference to the drawings. This exemplary embodiment is a form serving as the basis for the exemplary embodiments described later.

[0014] (Configuration of Optical Space Communication System) A configuration of an optical space communication system including an optical space communication apparatus according to the present exemplary embodiment will be described with reference to FIG. 1. FIG. 1 is a block diagram showing a configuration of an optical space communication system 400. The optical space communication system 400 includes a plurality of optical space communication apparatuses 1 and 101, and implements spatial multiplexing transmission through simultaneous connection of a plurality of beams. Although two optical space communication apparatuses 1 and 101 are illustrated in FIG. 1, the number is not limited thereto. In the following description, the description will be centered on one optical space communication apparatus 1, and the other optical space communication apparatus 101 will be described as an optical space communication apparatus that is a communication partner of the optical space communication apparatus 1, but these optical space communication apparatuses 1 and 101 may have the same configuration.

[0015] (Configuration of Optical Space Communication Apparatus) As shown in FIG. 1, the optical space communication apparatus 1 according to the present exemplary embodiment includes a plurality of light transmitting units 10-1 to 10-n, and an optical axis adjusting unit 20. The plurality of light transmitting units 10-1 to 10-n and the optical axis adjusting unit 20 are an implementation example of light transmitting means and optical axis adjusting means in the claims.

[0016] (Light Transmitting Units 10-1 to 10-n) Optical communication media transmitted from each of the plurality of light transmitting units 10-1 to 10-n are received by a plurality of light receiving units 130-1 to 130-n of the optical space communication apparatus 101 that is the communication partner. The optical communication medium is a directional optical communication medium, and although specific examples do not limit the exemplary embodiments, an example thereof is an electromagnetic wave in a high frequency region having a frequency of approximately 10 GHz or higher. Electromagnetic waves in the frequency region may include millimeter waves, submillimeter waves, infrared light, visible light, ultraviolet light, and the like.

[0017] As an example, the light transmitting units 10-1 to 10-n direct and transmit the electromagnetic waves in the above frequency range within a predetermined angle range, thereby being used for communication as the above-described directional optical communication medium. Here, although a specific configuration for the light transmitting units 10-1 to 10-n to direct the electromagnetic waves in the above frequency range does not limit the present exemplary embodiment, as an example, the light transmitting units 10-1 to 10-n are • Beamforming antennas that direct and transmit millimeter waves and submillimeter waves within a predetermined angular range. • Collimator that collimates infrared, visible, or ultraviolet light. • Laser oscillators that generate infrared, visible, or ultraviolet lasers. • A modulator that modulates a laser by changing the phase of the liquid crystal. The configuration can include the following:

[0018] By directing and transmitting electromagnetic waves in the above frequency range, which constitute the optical communication medium, the light transmitting units 10-1 to 10-n increase the energy density of the optical communication medium, thereby enabling communication with a more distant communication partner using the optical communication medium.

[0019] The number of light-transmitting units in the optical spatial communication device 1 is not limited to this exemplary embodiment. Furthermore, the light-transmitting units 10-1 to 10-n may be configured to be capable of receiving light (receiving light from an optical communication medium) in addition to transmitting light (transmitting light from an optical communication medium).

[0020] (Optical axis alignment section 20) The optical axis alignment unit 20 aligns the optical axes of each of the multiple light transmitting units 10-1 to 10-n with respect to each of the multiple light receiving units 130-1 to 130-n provided by the optical space communication device 101 of the communication partner.

[0021] To align the optical axis, the optical axis alignment unit 20 causes at least one of the multiple light transmitting units 10-1 to 10-n to emit scanning light 3 while changing direction. In Figure 1, light transmitting unit 10-3 is used as at least one of the light transmitting units. The optical axis alignment unit 20 controls the light transmitting unit 10-3 to emit scanning light 3 while changing direction. The scanning light 3 uses the directional optical communication medium described above. The scanning light 3 is received by one or more light receiving units (light receiving unit 130-3 in the example of Figure 1) through scanning with the scanning light 3.

[0022] Here, scanning with scanning light 3 refers, for example, to a search performed to identify one or more light-receiving units. The term "scan" is not intended to prescribe a specific scanning order or anything like that. Scanning light 3 contains information about the light-transmitting unit from which the light was transmitted and information about the direction in which it was transmitted.

[0023] The optical axis alignment unit 20 aligns the optical axes of light-emitting units (light-emitting units 10-1, 10-2, 10-4 to 10-n in the example of Figure 1) that are different from at least one light-emitting unit (light-emitting unit 10-3 in the example of Figure 1), based on the transmission direction of the scanning light 3 transmitted from at least one light-emitting unit (light-emitting unit 10-3 in the example of Figure 1) and received by the corresponding light-receiving unit.

[0024] As mentioned above, the scanning light 3 contains various information, and when the corresponding light receiving unit can receive the scanning light 3, that is, when the optical axis alignment is achieved, the information contained in the scanning light 3 can be acquired by the optical axis alignment unit 20. In one example, when the light receiving unit 130-3 of the optical space communication device 101 of the communication partner receives the scanning light 3 used for the scan described above, the light receiving unit 130-3 emits a response light, which is a response to the scanning light 3. This response light is transmitted from the optical space communication device 101 of the communication partner to the optical space communication device 1. This response light may be transmitted using optical space communication with an optical communication medium, or it may be transmitted wirelessly or via other means. In order to realize a configuration in which the response light uses optical space communication with an optical communication medium, in one example, the multiple light receiving units 130-1 to 130-n are also configured to be able to transmit light (transmit optical communication medium) and receive light (receive optical communication medium), similar to the light transmitting units 10-1 to 10-n. In this example, a response light is emitted from the light receiving unit 130-3, which receives the scanning light 3. This response light is then received by one of the light transmitting units 10-1 to 10-n of the optical space communication device 1.

[0025] The optical axis alignment unit 20 aligns the optical axes of light transmitting units 10-1, 10-2, and 10-4 to 10-n based on the response light received by any of the light transmitting units 10-1 to 10-n. As an example, the optical axis alignment unit 20 identifies the azimuth angle, elevation angle, and depression angle of the light receiving unit 130-3 that emitted the response light, starting from the light transmitting unit 10-3, for which optical axis alignment is complete.

[0026] The optical axis alignment unit 20 adjusts the output direction of the other light-emitting units (10-1, 10-2, 10-4, ..., 10-N) based on the output direction of the scanning light emitted from the light-emitting unit 10-3. For example, the optical axis alignment unit 20 may adjust the output direction of the other light-emitting units to be in the same direction as the output direction of the scanning light emitted from the light-emitting unit 10-3.

[0027] As described above, in the optical space communication device 1 and the optical space communication system 400 including the optical space communication device 1 according to this exemplary embodiment, an optical axis alignment unit 20 is provided to align the optical axis of each of the multiple light transmitting units 10-1 to 10-n with each of the multiple light receiving units 130-1 to 130-n provided by the optical space communication device 101, which is the communication partner of the optical space communication device 1. The optical axis alignment unit 20 is configured to cause at least one of the multiple light transmitting units 10-1 to 10-n (light transmitting unit 10-3) to emit scanning light while changing direction, and to align the optical axis of a light transmitting unit (light transmitting unit 10-1, 10-2, 10-4 to 10-n) that is different from at least one light transmitting unit (light transmitting unit 10-3) based on the emission direction of the scanning light emitted from the light transmitting unit 10-3 and received by the corresponding light receiving unit (light receiving unit 130-3). Therefore, according to this exemplary embodiment, the effect is obtained that the optical axis alignment of the transmitting and receiving units between the optical space communication devices 1 and 101 can be made more efficient. Specifically, since the optical axis of the other light transmitting unit is aligned based on the scanning direction of the scanning light whose optical axis is already aligned, the time required to align the optical axis can be shortened compared to a configuration in which multiple light transmitting units each perform optical axis alignment independently.

[0028] (Flowchart of optical space communication method) The flow of the optical spatial communication method S1 according to this exemplary embodiment will be explained with reference to Figure 2. Figure 2 is a flowchart showing the flow of the optical spatial communication method S1.

[0029] As shown in Figure 2, the optical spatial communication method S1 includes an optical axis alignment step (S10) in which the optical axis of each of the multiple light transmitting units is aligned with the optical axis of each of the multiple light receiving units. This optical axis alignment step (S10) includes steps S11 and S12.

[0030] (Step S11) First, in step S11, the optical axis alignment unit 20 controls at least one light transmitting unit (light transmitting unit 10-3) to transmit scanning light while changing direction. This performs a scan using scanning light, and identifies one or more light receiving units of the optical space communication device 101 of the communication partner. The specific processing details here have been described above, so they will not be explained here.

[0031] (Step S12) In the next step S12, the optical axes of light-transmitting units (light-transmitting units 10-1, 10-2, 10-4~10-n) that are different from at least one light-transmitting unit (light-transmitting unit 10-3) are aligned based on the transmission direction of the scanning light transmitted from at least one light-transmitting unit (light-transmitting unit 10-3) and received by the corresponding light-receiving unit (light-receiving unit 130-3). The specific processing details here have been described above, so an explanation is omitted here.

[0032] As described above, the optical space communication method S1 according to this exemplary embodiment includes aligning the optical axis of each of the plurality of light transmitting units with respect to each of the plurality of light receiving units (S10), and the aligning of the optical axes (S10) includes causing at least one of the plurality of light transmitting units to emit scanning light while changing direction (S11), and aligning the optical axis of a light transmitting unit different from the at least one light transmitting unit based on the emission direction of the scanning light emitted from the at least one light transmitting unit and received by the corresponding light receiving unit (S12). Therefore, the optical space communication method S1 according to this exemplary embodiment has the effect of making optical axis alignment more efficient.

[0033] [Exemplary Embodiment 2] A second exemplary embodiment of the present invention will be described in detail with reference to the drawings. Components having the same function as those described in Exemplary Embodiment 1 will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0034] (Configuration of the optical space communication system) The configuration of the optical space communication system, including the optical space communication device according to this exemplary embodiment, will be described with reference to Figure 3. Figure 3 is a block diagram showing the configuration of the optical space communication system 400. The optical space communication system 400 is a system that realizes spatial multiplex transmission, including a first optical space communication device 1 including a plurality of light transmitting units 10-1 to 10-n, and a second optical space communication device 101 including a plurality of light receiving units 130-1 to 130-n corresponding to the plurality of light transmitting units 10-1 to 10-n. In Figure 3, the first and second optical space communication devices 1 and 101 are shown as examples, but the number of optical space communication devices is not limited to these. In the following description, the first optical space communication device 1 will be described as the main focus, and the second optical space communication device 101 will be described as the communication partner of the first optical space communication device 1. Note that these optical space communication devices 1 and 101 can have the same configuration.

[0035] (First optical space communication device 1) As shown in Figure 3, the first optical space communication device 1 according to this exemplary embodiment comprises a plurality of light transmitting units 10-1 to 10-n and an optical axis alignment unit 20. The plurality of light transmitting units 10-1 to 10-n and the optical axis alignment unit 20 are examples of implementations of the light transmitting means and optical axis alignment means within the scope of the claims.

[0036] (Light transmitting section 10-1 to 10-n) The optical communication medium transmitted from each of the multiple light transmitting units 10-1 to 10-n has been described above, so its description is omitted here. Below, the configuration of each light transmitting unit 10-1 to 10-n will be described using an example shown in Figure 4. In the following, when a description is common to all of the light transmitting units 10-1 to 10-n, it will be described as light transmitting unit 10.

[0037] Figure 4 shows an example of the configuration of the light transmitting unit 10. The light transmitting unit 10 comprises a light-emitting unit 11 and a light modulator 12. The light-emitting unit 11 and the light modulator 12 are controlled by the optical axis alignment unit 20.

[0038] The light-emitting unit 11 includes a well-known light-emitting element and may include a lens or the like. The light emitted from the light-emitting unit 11 is incident on the optical modulator 12. The illumination of the light-emitting unit 11 is controlled by the optical axis alignment unit 20.

[0039] The optical modulator 12 receives light from the light-emitting unit 11, generates light under desired conditions, and emits it. Desired conditions may include, for example, a desired wavelength, desired light intensity, and desired angle. The optical modulator 12 is controlled by the optical axis alignment unit 20 to generate light under the desired conditions. The light emitted from the optical modulator 12 is directed towards the light-receiving unit 130 of the second optical space communication device 101.

[0040] (Second optical space communication device 101) The second optical space communication device 101 includes a plurality of light receiving units 130-1 to 130-n corresponding to the plurality of light transmitting units 10-1 to 10-n of the first optical space communication device 1. The second optical space communication device 101 also includes an optical axis alignment unit 120.

[0041] (Light receiving section 130-1~130-n) Here, the configuration of the light-receiving units 130-1 to 130-n of the second optical space communication device 101 will be explained using an example shown in Figure 5. The multiple light-receiving units 130-1 to 130-n are one example of the implementation of the light-receiving means in the claims. In the following, when the explanation is common to all of the light-receiving units 130-1 to 130-n, they will be referred to as light-receiving unit 130.

[0042] Figure 5 shows an example of the configuration of the light receiving unit 130. The light receiving unit 130 comprises a condensing lens 131, a light receiving element 132, and a receiving circuit 133. The optical communication medium emitted from the light transmitting unit 10 of the first optical space communication device 1 is focused by the condensing lens 131 and received by the light receiving element 132, after which it is processed as a signal in the receiving circuit 133.

[0043] (Optical axis alignment section 120) The optical axis alignment unit 120 has the same configuration as the optical axis alignment unit 20 provided in the first optical space communication device 1. That is, the optical axis alignment unit 120 is one example of an implementation of the optical axis alignment means in the claims. The optical axis alignment unit 120 controls each component of the light receiving unit 130.

[0044] (Arrangement of the light-transmitting unit) Figure 6 shows an example of how the multiple light-transmitting units 10-1 to 10-n can be arranged in the first optical space communication device 1. Figure 6 is a view of the multiple light-transmitting units 10-1 to 10-n from their respective light-emitting sides. The multiple light-transmitting units 10-1 to 10-n are arranged in a matrix within a plane 4. The arrangement of the transmitting units is not limited to that shown in Figure 6; for example, the arrangement shown in Figure 7 may also be used. Figure 7 is a view of the multiple light-transmitting units 10-1 to 10-n from their respective light-emitting sides, similar to Figure 6. As shown in the two examples in Figure 7, the multiple light-transmitting units 10-1 to 10-n may be arranged in an array (left side of Figure 7), or they may be arranged in a ring (right side of Figure 7).

[0045] The light-receiving unit is positioned opposite each light-transmitting unit, corresponding to the arrangement of the light-transmitting units. Note that the arrangement of the light-transmitting and light-receiving units is not limited to the examples provided.

[0046] (Optical axis alignment section 20) The optical axis alignment section 20 shown in Figure 3 has been described in the exemplary embodiment 1 above, so its explanation is omitted here.

[0047] Figure 8 schematically shows a situation where the light-transmitting units 10-1 to 10-n are tilted in the Z direction for some reason. Here, the Z direction can be defined as the optical axis direction. When the light-transmitting units 10-1 to 10-n are tilted in the Z direction, the spacing between the light-transmitting units 10-1 to 10-n and the spacing between the light-receiving units 130-1 to 130-n become misaligned. In this case, the optical axis alignment unit 20 cannot align the optical axis of a light-transmitting unit other than the one that has already transmitted scanning light and completed optical axis alignment.

[0048] Therefore, in this exemplary embodiment, the optical axis alignment unit 20 shown in Figure 3 aligns the optical axes of light-emitting units different from the three or more light-emitting units based on the transmission direction of each scanning light transmitted from each of the three or more light-receiving units and received by the three or more corresponding light-receiving units. Specifically, the optical axis alignment unit 20 causes each of the three light-emitting units 10-1, 10-2, and 10-3 arranged in Figure 9 to transmit the scanning light 3 described in exemplary embodiment 1. Preferably, the three light-emitting units 10-1, 10-2, and 10-3 arranged in Figure 9 are light-emitting units located at three points where lines connecting two light-emitting units intersect perpendicularly, as shown by the dashed lines in Figure 9.

[0049] In the configuration shown in Figure 9, in which scanning light is transmitted to the three light transmitting units 10-1, 10-2, and 10-3, the optical axis alignment unit 20 aligns the optical axes of the other light transmitting units 10-4 to 10-n based on the direction of the scanning light transmitted by each of the three light transmitting units 10-1, 10-2, and 10-3 (the direction of the light that has been received by the corresponding light receiving units 130-1, 130-2, and 130-3, after so-called optical axis alignment has been completed).

[0050] In one example, using the XY coordinates shown in Figure 9, the position of light transmitting unit 10-2 on plane 4 is set as the origin (0,0), the position of light transmitting unit 10-1 on plane 4 is set as (0,1), the position of light transmitting unit 10-3 on plane 4 is set as (-1,0), and the transmission direction of light transmitting units 10-1 to 10-3 is set as D 1~3 In this case, the emission direction D of the light-emitting unit located at (x, y) on the plane 4 may be calculated using the following formula (1). D=-x×(D3-D2)+y×(D1-D2) … (1)

[0051] (modified version) As described above, by using the results of pre-aligning the optical axes of the three light-transmitting units to align the optical axes of the other light-transmitting units, it is possible to align the optical axes of the other light-transmitting units even if one of the light-transmitting units is tilted in the Z direction. However, one aspect of the present invention is not limited to the configuration using three light-transmitting units, and the first optical space communication device 1 and the second optical space communication device 101 may each detect the tilt in the Z direction using a detection device such as a ground axis sensor.

[0052] For example, when adjusting the transmission direction of other light-transmitting units (10-1, 10-2, 10-4, ..., 10-N) based on the transmission direction of scanning light transmitted from light-transmitting unit 10-3 using a detection device such as a geoaxial sensor, the optical axis alignment unit 20 may operate as follows. First, the optical axis alignment unit 20 calculates the relative position of the other light-transmitting units in three-dimensional space with respect to light-transmitting unit 10-3 based on the tilt of the first optical space communication device 1 in the Z direction and the positional relationship between each light-transmitting unit. Next, the optical axis alignment unit 20 calculates the relative position of the light-receiving unit 130-3 in three-dimensional space with respect to light-transmitting unit 10-3 based on the transmission direction of light-transmitting unit 10-3. Next, the optical axis alignment unit 20 calculates the relative positions in three-dimensional space of the other light receiving units (130-1, 130-2, 130-4, ..., 130-N) with respect to the light transmitting unit 10-3, based on the relative position of the light receiving unit 130-3 with respect to the light transmitting unit 10-3, the positional relationship between each light receiving unit of the second optical space communication device 101, and the tilt of the second optical space communication device 101 in the Z direction. Then, the optical axis alignment unit 20 may determine the transmission direction of the other light transmitting units from the relative positions in three-dimensional space of the other light transmitting units with respect to the light transmitting unit 10-3 and the relative positions in three-dimensional space of the other light receiving units with respect to the light transmitting unit 10-3.

[0053] (Effects of optical space communication devices 1 and 101) In the optical space communication devices (first optical space communication device 1 and second optical space communication device 101) and the optical space communication system 400 including these optical space communication devices, an optical axis alignment unit 20 is provided for each of the multiple light receiving units 130-1 to 130-n provided in the optical space communication device 101, which is the communication partner of the optical space communication device 1, to align the optical axis of each of the multiple light transmitting units 10-1 to 10-n. The optical axis alignment unit 20 is configured to cause at least one of the multiple light transmitting units 10-1 to 10-n (light transmitting unit 10-3) to emit scanning light while changing direction, and to align the optical axis of a light transmitting unit (light transmitting unit 10-1, 10-2, 10-4 to 10-n) that is different from at least one light transmitting unit (light transmitting unit 10-3) based on the emission direction of the scanning light emitted from the light transmitting unit 10-3 and received by the corresponding light receiving unit (light receiving unit 130-3). Therefore, according to this exemplary embodiment, the effect is obtained that the optical axis alignment of the transmitting and receiving units between the optical space communication devices 1 and 101 can be made more efficient. Specifically, since the optical axis of the other light transmitting unit is aligned based on the scanning direction of the scanning light whose optical axis is already aligned, the time required to align the optical axis can be shortened compared to a configuration in which multiple light transmitting units each perform optical axis alignment independently.

[0054] Furthermore, in the optical space communication device (first optical space communication device 1 and second optical space communication device 101) according to this exemplary embodiment, the optical axis alignment unit 20 is configured to align the optical axis of a light-emitting unit different from the three or more light-emitting units, based on the transmission direction of each scanning light emitted from three or more light-emitting units and received by three or more corresponding light-receiving units. Therefore, according to this exemplary embodiment, even if the multiple light-emitting units are tilted in the Z direction, the optical axis of a light-emitting unit different from the three or more light-emitting units can be aligned based on the transmission direction of each scanning light.

[0055] [Exemplary Embodiment 3] A third exemplary embodiment of the present invention will be described in detail with reference to the drawings. Components having the same function as those described in the above-described exemplary embodiments 1 and 2 will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0056] (Configuration of the optical space communication system) The configuration of the optical space communication system, including the optical space communication device according to this exemplary embodiment, will be described with reference to Figure 10. Figure 10 is a block diagram showing the configuration of the optical space communication system 400. The optical space communication system 400 has the same basic configuration as the optical space communication system 400 of exemplary embodiment 2 shown in Figure 3. On the other hand, this exemplary embodiment 3 differs from exemplary embodiment 2 in that, before the scanning light is transmitted from the light transmitting unit 10-3 under the control of the optical axis alignment unit 20, a preliminary scanning light is transmitted from the light transmitting unit 10-3 under the control of the optical axis alignment unit 20. In short, the control content of the optical axis alignment unit 20 is different from that of exemplary embodiment 2. The control content of the optical axis alignment unit 20 of this exemplary embodiment will be described below.

[0057] (Optical axis alignment section 20) The optical axis alignment unit 20 causes at least one light transmitting unit (light transmitting unit 10-3) to send out a preliminary scanning light 33, which is a bundle of multiple light beams, and controls the direction of the scanning light to be sent out by at least one light transmitting unit (light transmitting unit 10-3) based on which light receiving unit (light receiving unit 130-3) receives the preliminary scanning light 33.

[0058] The pre-scanning light 33, which is composed of multiple bundled light beams, is an optical communication medium transmitted by controlling the light transmitting unit 10-3. By bundling multiple light beams, the transmission range of the light is wider than that of the subsequent scanning light 3. The pre-scanning light 33 is transmitted over a wide range by the modulation function of the optical modulator 12 (Figure 4) of the exemplary embodiment 2 described above. The optical axis alignment unit 20 causes the light transmitting unit 10-3 to transmit the pre-scanning light 33 toward the light receiving units 130-1 to 130-n.

[0059] In the second optical space communication device 101, which is the device from which the preliminary scanning light is transmitted, at least one of the light-receiving units 130-1 to 130-n (light-receiving unit 130-3) receives the preliminary scanning light. Since the beam diameter of the preliminary scanning light 33 is wider than the beam diameter of the scanning light 3 transmitted later, it is more easily received by the light-receiving unit, thus enabling a reduction in the scanning time using the preliminary scanning light.

[0060] The light-receiving unit (light-receiving unit 130-3 in this example) that receives the preliminary scanning light 33 sends out a preliminary response light in response to the reception of light toward the first optical space communication device 1. This preliminary response light is basically the same as the response light described in exemplary embodiment 1. This preliminary response light is accompanied by information indicating which light-receiving unit the response came from. As an example, this information is the position information of the light-receiving unit that sent out the preliminary response light.

[0061] The first optical space communication device 1, upon receiving the preliminary response light, controls the direction of the scanning light transmitted by at least one light transmitting unit (light transmitting unit 10-3) via the optical axis alignment unit 20. For example, the optical axis alignment unit 20 acquires position information of the light receiving unit 130-3 that transmitted the preliminary response light from the preliminary response light, and uses this position information to control the direction of the scanning light.

[0062] (Effects of the optical spatial communication system 400 and the first and second optical spatial communication devices 1 and 101) In the optical space communication devices (first optical space communication device 1 and second optical space communication device 101) and the optical space communication system 400 including these optical space communication devices, an optical axis alignment unit 20 is provided for each of the multiple light receiving units 130-1 to 130-n provided in the optical space communication device 101, which is the communication partner of the optical space communication device 1, to align the optical axis of each of the multiple light transmitting units 10-1 to 10-n. The optical axis alignment unit 20 is configured to cause at least one of the multiple light transmitting units 10-1 to 10-n (light transmitting unit 10-3) to emit scanning light while changing direction, and to align the optical axis of a light transmitting unit (light transmitting unit 10-1, 10-2, 10-4 to 10-n) that is different from at least one light transmitting unit (light transmitting unit 10-3) based on the emission direction of the scanning light emitted from the light transmitting unit 10-3 and received by the corresponding light receiving unit (light receiving unit 130-3). Therefore, according to this exemplary embodiment, the effect is obtained that the optical axis alignment of the transmitting and receiving units between the optical space communication devices 1 and 101 can be made more efficient. Specifically, since the optical axis of the other light transmitting unit is aligned based on the scanning direction of the scanning light whose optical axis is already aligned, the time required to align the optical axis can be shortened compared to a configuration in which multiple light transmitting units each perform optical axis alignment independently.

[0063] Furthermore, in the optical space communication devices (first optical space communication device 1 and second optical space communication device 101) according to this exemplary embodiment, the optical axis alignment unit 20 causes at least one light transmitting unit (light transmitting unit 10-3) to send out a preliminary scanning light 33 in which multiple light beams are bundled together, and controls the direction of transmission of the scanning light to be sent out by at least one light transmitting unit (light transmitting unit 10-3) based on which light receiving unit (light receiving unit 130-3) receives the preliminary scanning light 33. Therefore, according to this exemplary embodiment, a preliminary scan using a preliminary scanning light that is transmitted over a wide area in bundled form of multiple light beams is performed before the scan with the scanning light. As a result, the approximate optical axis direction can be estimated by the preliminary scan, making optical axis alignment more efficient.

[0064] (Flowchart of optical space communication method) The flow of the optical space communication method S1 according to this exemplary embodiment will be explained with reference to Figure 11. Figure 11 is a flowchart showing the flow of the optical space communication method S1 using the optical space communication system according to this exemplary embodiment.

[0065] As shown in Figure 2, the optical spatial communication method S1 includes an optical axis alignment step (S10) in which the optical axis of each of the multiple light transmitting units is aligned with the optical axis of each of the multiple light receiving units. This optical axis alignment step (S10) includes steps S21, S22, S23, and S24.

[0066] (Step S21) In step S21, the optical axis alignment unit 20 controls the light transmission unit 10-3 so that a preliminary scanning beam, which is a bundle of multiple beams of light, is sent out from the light transmission unit 10-3. The preliminary scan using the preliminary scanning beam has been described above, so a detailed explanation is omitted here.

[0067] (Step S22) In step S22, the optical axis alignment unit 20 receives a preliminary response light from the light receiving unit 130-3, which received the preliminary scanning light sent in step S21, and detects which light receiving unit received the preliminary scanning light.

[0068] (Step S23) In step S23, based on the detection result from step S22, the optical axis alignment unit 20 controls the direction of the scanning light to be sent to the light transmitting unit 10-3. Since the control of the scanning light's direction has been described above, a detailed explanation is omitted here. The scanning light is sent out while changing direction.

[0069] (Step S24) In step S24, the optical axes of light-transmitting units (light-transmitting units 10-1, 10-2, 10-4~10-n) that are different from light-transmitting unit 10-3 are aligned based on the transmission direction of the scanning light transmitted from light-transmitting unit 10-3 and received by the corresponding light-receiving unit 130-3. The specific processing details here have been described above, so they will not be explained here.

[0070] As described above, in the optical space communication method according to this exemplary embodiment, a method is employed in which at least one light transmitting unit (light transmitting unit 10-3) transmits a preliminary scanning light 33 in which multiple lights are bundled, and the transmission direction of the scanning light to be transmitted by at least one light transmitting unit (light transmitting unit 10-3) is controlled based on which light receiving unit (light receiving unit 130-3) receives the preliminary scanning light 33. Therefore, the effect is obtained in which the optical axis alignment of the transmitting and receiving units between the optical space communication devices 1 and 101 can be made more efficient.

[0071] [Exemplary Embodiment 4] A fourth exemplary embodiment of the present invention will be described in detail with reference to the drawings. Components having the same function as those described in exemplary embodiments 1, 2, and 3 above will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0072] (Configuration of the optical space communication system) The configuration of the optical space communication system, including the optical space communication device according to this exemplary embodiment, will be described with reference to Figure 12. Figure 12 is a block diagram showing the configuration of the optical space communication system 400. The optical space communication system 400 has the same basic configuration as the optical space communication system 400 of the exemplary embodiment described above. On the other hand, this exemplary embodiment 4 differs from the exemplary embodiment described above in that each light transmitting unit 10-1 to 10-n transmits scanning light to different ranges from each other. The control contents of the optical axis alignment unit 20 of this exemplary embodiment will be described below.

[0073] (Optical axis alignment section 20) The optical axis alignment unit 20 causes two or more light transmitting units to emit scanning light in different ranges from each other, and aligns the optical axis of a light transmitting unit other than the one that emitted the received scanning light, based on which light receiving unit received the scanning light. Figure 12 shows an example in which scanning light is emitted from all light transmitting units 10-1 to 10-n, and these scanning lights are emitted in different ranges from each other.

[0074] The scanning light emitted from each light transmitting unit 10-1 to 10-n is configured to be identifiable, and the light receiving unit 130 is configured to identify which light transmitting unit emitted the scanning light that it received. Identification may be performed by the optical axis alignment unit 120 of the second optical space communication device 101, which is the communication partner, or by the optical axis alignment unit 20.

[0075] In the second optical space communication device 101, at least one of the light receiving units 130-1 to 130-n (light receiving unit 130-3) receives the scanning light. Based on the received scanning light, a light transmitting unit (light transmitting unit 10-3 in Figure 12) whose optical axis is aligned with that at least one light receiving unit (light receiving unit 130-3) is identified. The optical axis alignment unit 20 uses the light transmission direction of the light transmitting unit whose optical axis is aligned to align the optical axes of the other light transmitting units (light transmitting units 10-1, 10-2, 10-4 to 10-n) in the same manner as in the exemplary embodiment described above.

[0076] (Effects of the optical spatial communication system 400 and the first and second optical spatial communication devices 1 and 101) In the optical space communication devices (first optical space communication device 1 and second optical space communication device 101) and the optical space communication system 400 including these optical space communication devices, an optical axis alignment unit 20 is provided for each of the multiple light receiving units 130-1 to 130-n provided in the optical space communication device 101, which is the communication partner of the optical space communication device 1, to align the optical axis of each of the multiple light transmitting units 10-1 to 10-n. The optical axis alignment unit 20 is configured to cause at least one of the multiple light transmitting units 10-1 to 10-n (light transmitting unit 10-3) to emit scanning light while changing direction, and to align the optical axis of a light transmitting unit (light transmitting unit 10-1, 10-2, 10-4 to 10-n) that is different from at least one light transmitting unit (light transmitting unit 10-3) based on the emission direction of the scanning light emitted from the light transmitting unit 10-3 and received by the corresponding light receiving unit (light receiving unit 130-3). Therefore, according to this exemplary embodiment, the effect is obtained that the optical axis alignment of the transmitting and receiving units between the optical space communication devices 1 and 101 can be made more efficient. Specifically, since the optical axis of the other light transmitting unit is aligned based on the scanning direction of the scanning light whose optical axis is already aligned, the time required to align the optical axis can be shortened compared to a configuration in which multiple light transmitting units each perform optical axis alignment independently.

[0077] Furthermore, in the optical space communication device (first optical space communication device 1 and second optical space communication device 101) according to this exemplary embodiment, the optical axis alignment unit 20 is configured to cause two or more light transmitting units to transmit scanning light in different ranges from each other, and to align the optical axis of a light transmitting unit different from the light transmitting unit that transmitted the received scanning light, based on which light receiving unit received the scanning light. Therefore, according to this exemplary embodiment, the optical axis alignment in scanning using scanning light can be made more efficient, and thus the optical axis alignment of multiple light transmitting units can be made more efficient.

[0078] [Examples of implementation using software] Some or all of the functions of the optical space communication devices 1, 101 may be implemented by hardware such as integrated circuits (IC chips) or by software.

[0079] In the latter case, the optical space communication devices 1 and 101 are implemented by a computer that executes instructions for a program, which is software that realizes each function. An example of such a computer (hereinafter referred to as computer C) is shown in Figure 13. Computer C comprises at least one processor C1 and at least one memory C2. The memory C2 stores a program P that causes computer C to operate as an optical space communication device 1 or 101. In computer C, the processor C1 reads the program P from the memory C2 and executes it, thereby realizing each function of the optical space communication devices 1 and 101.

[0080] Processor C1 can include, for example, a CPU (Central Processing Unit), GPU (Graphic Processing Unit), DSP (Digital Signal Processor), MPU (Micro Processing Unit), FPU (Floating Point Number Processing Unit), PPU (Physics Processing Unit), microcontroller, or a combination thereof. Memory C2 can include, for example, flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof.

[0081] Computer C may also be equipped with RAM (Random Access Memory) for loading program P at runtime and for temporarily storing various data. Furthermore, computer C may be equipped with communication interfaces for sending and receiving data with other devices. Additionally, computer C may be equipped with input / output interfaces for connecting input / output devices such as keyboards, mice, displays, and printers.

[0082] Furthermore, program P can be recorded on a non-temporary, tangible recording medium M that is readable by computer C. Such a recording medium M could be, for example, tape, disk, card, semiconductor memory, or programmable logic circuitry. Computer C can acquire program P via such a recording medium M. Program P can also be transmitted via a transmission medium. Such a transmission medium could be, for example, a communication network or broadcast waves. Computer C can also acquire program P via such a transmission medium.

[0083] [Additional Note 1] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. For example, embodiments obtained by appropriately combining the technical means disclosed in the embodiments described above are also included in the technical scope of the present invention.

[0084] [Additional Note 2] Some or all of the embodiments described above may also be described as follows. However, the present invention is not limited to the embodiments described below.

[0085] (Note 1) Optical space communication device, Multiple light transmission means, The optical spatial communication device includes an optical axis alignment means for aligning the optical axis of each of the multiple light transmitting means with respect to each of the multiple light receiving means provided by the communication partner of the optical spatial communication device, The optical axis alignment means is At least one of the plurality of light transmitting means is made to transmit scanning light while changing direction, Based on the transmission direction of the scanning light transmitted from at least one of the light transmitting means and received by the corresponding light receiving means, the optical axis of a light transmitting means different from that of the at least one light transmitting means is aligned. An optical space communication device characterized by the following features.

[0086] According to the above configuration, in an embodiment comprising multiple light transmitting means and light receiving means, optical axis alignment can be made more efficient.

[0087] (Note 2) The optical axis alignment means is The at least one light transmitting means is made to transmit a preliminary scanning light in which multiple lights are bundled together. The optical space communication device according to Appendix 1, characterized in that it controls the direction of transmission of the scanning light to be transmitted by at least one light transmitting means based on which of the light receiving means has received the preliminary scanning light.

[0088] According to the above configuration, a preliminary scan using pre-scanning light, which is a bundle of multiple light beams transmitted over a wide area, is performed before the scan using the scanning light. This allows for a rough estimation of the optical axis direction through the preliminary scan, thus improving the efficiency of optical axis alignment.

[0089] (Note 3) The optical axis alignment means is The optical space communication device according to Appendix 1, characterized in that, based on the transmission direction of each scanning light transmitted from three or more light transmitting means and received by three or more corresponding light receiving means, the optical axis of a light transmitting means different from that of the three or more light transmitting means is aligned.

[0090] According to the above configuration, even if multiple light-transmitting units are tilted in the Z direction, the optical axes of three or more light-transmitting units that are different from the above three can be aligned based on the transmission direction of each scanning light.

[0091] (Note 4) The optical axis alignment means is By having two or more of the light transmitting means transmit scanning light in different ranges from each other, The optical space communication device according to Appendix 1, characterized in that, based on which of the light-receiving means the scanning light was received, the optical axis of a light-transmitting means different from the light-transmitting means that sent out the received scanning light is aligned.

[0092] According to the above configuration, the optical axis alignment in scanning using scanning light can be made more efficient, and therefore the optical axis alignment of multiple light transmitting units can be made more efficient.

[0093] (Note 5) Includes multiple optical space communication devices, Of the aforementioned plurality of optical space communication devices, at least one of the optical space communication devices is Multiple light transmission means, The optical axis alignment means is provided for aligning the optical axis of each of the plurality of light transmitting means with respect to each of the plurality of light receiving means provided by the optical space communication device that will be the communication partner, The optical axis alignment means is At least one of the plurality of light transmitting means is made to transmit scanning light while changing direction, Based on the transmission direction of the scanning light transmitted from at least one of the light transmitting means and received by the corresponding light receiving means, the optical axis of a light transmitting means different from that of the at least one light transmitting means is aligned. An optical spatial communication system characterized by the following features.

[0094] According to the above configuration, the alignment of the optical axes of multiple light transmitting means and light receiving means can be made more efficient.

[0095] (Note 6) An optical space communication method comprising a first optical space communication device equipped with multiple light transmitting means and a second optical space communication device equipped with multiple light receiving means, which is the communication partner of the first optical space communication device, This includes aligning the optical axis of each of the multiple light-transmitting means with respect to each of the multiple light-receiving means, To align the optical axis, To cause at least one of the plurality of light transmitting means to transmit scanning light while changing direction, This includes aligning the optical axis of a light transmitting means different from the at least one light transmitting means based on the transmission direction of the scanning light transmitted from the at least one light transmitting means and received by the corresponding light receiving means, A method of optical space communication characterized by the following features.

[0096] According to the above configuration, the alignment of the optical axes of multiple light transmitting means and light receiving means can be made more efficient.

[0097] (Note 7) A program for operating a computer as an optical space communication device as described in any one of the appendices 1 to 4, characterized in that the computer functions as each of the means described above.

[0098] (Note 8) An optical space communication device having at least one processor, The aforementioned processor, Light transmission processing from multiple light transmission means, For each of the multiple light receiving means provided by the communication partner of the optical space communication device, an optical axis alignment process is performed to align the optical axis of each of the multiple light transmitting means. In the aforementioned optical axis alignment process, The process of causing at least one of the plurality of light transmitting means to transmit scanning light while changing direction, An optical space communication device that performs the process of aligning the optical axis of a light transmitting means different from the at least one light transmitting means based on the transmission direction of the scanning light transmitted from the at least one light transmitting means and received by the corresponding light receiving means.

[0099] Furthermore, this optical space communication device may also be equipped with memory, and this memory may store a program for causing the processor to perform each of the aforementioned processes. This program may also be recorded on a computer-readable, non-temporary, tangible recording medium. [Explanation of Symbols]

[0100] 1 Optical space communication device (optical space communication device) 101 Optical space communication device (Optical space communication device of the communication partner) 3 Scanning light 10, 10-1 to 10-n light transmitting section 11 Light-emitting part 12 Optical modulators 33 Preliminary scanning light 130, 130-1~130-n light receiving section 131 Focusing lens 132 Photodetector 133 Receiving Circuit 400 Optical Space Communication Systems

Claims

1. Optical space communication device, Multiple light transmission means, The optical space communication device includes an optical axis alignment means for aligning the optical axis of each of the multiple light transmitting means with respect to each of the multiple light receiving means provided by the communication partner of the optical space communication device, The optical axis alignment means is At least one of the plurality of light transmitting means is made to transmit scanning light while changing direction, Based on the transmission direction of the scanning light transmitted from at least one of the light transmitting means and received by the corresponding light receiving means, the optical axis of a light transmitting means different from that of the at least one light transmitting means is aligned. The at least one light transmitting means is made to transmit a preliminary scanning light in which multiple lights are bundled together. Based on which of the light-receiving means the preliminary scanning light was received by the light-receiving means, the direction of transmission of the scanning light to be transmitted by at least one of the light-transmitting means is controlled. An optical space communication device characterized by the following features.

2. The optical axis alignment means is Based on the transmission direction of each scanning light emitted from three or more of the aforementioned light transmitting means and received by three or more corresponding light receiving means, the optical axis of a light transmitting means different from that of the three or more aforementioned light transmitting means is aligned. The optical space communication device according to feature 1.

3. The optical axis alignment means is By having two or more of the light transmitting means transmit scanning light in different ranges from each other, Based on which of the light-receiving means received the scanning light, the optical axis of a light-transmitting means different from the light-transmitting means that sent out the received scanning light is aligned. The optical space communication device according to feature 1.

4. Includes multiple optical space communication devices, Of the aforementioned plurality of optical space communication devices, at least one of the optical space communication devices is Multiple light transmission means, The optical axis alignment means is provided for aligning the optical axis of each of the plurality of light transmitting means with respect to each of the plurality of light receiving means provided by the optical space communication device that will be the communication partner, The optical axis alignment means is At least one of the plurality of light transmitting means is made to transmit scanning light while changing direction, Based on the transmission direction of the scanning light transmitted from at least one of the light transmitting means and received by the corresponding light receiving means, the optical axis of a light transmitting means different from that of the at least one light transmitting means is aligned. The at least one light transmitting means is made to transmit a preliminary scanning light in which multiple lights are bundled together. Based on which of the light-receiving means the preliminary scanning light was received by the light-receiving means, the direction of transmission of the scanning light to be transmitted by at least one of the light-transmitting means is controlled. An optical spatial communication system characterized by the following features.

5. An optical space communication method comprising a first optical space communication device equipped with multiple light transmitting means and a second optical space communication device equipped with multiple light receiving means, which is the communication partner of the first optical space communication device, This includes aligning the optical axis of each of the multiple light-transmitting means with respect to each of the multiple light-receiving means, To align the optical axis, To cause at least one of the plurality of light transmitting means to transmit scanning light while changing direction, Based on the transmission direction of the scanning light transmitted from at least one of the light transmitting means and received by the corresponding light receiving means, the optical axis of a light transmitting means different from that of the at least one light transmitting means is aligned. The at least one light transmitting means is made to transmit a preliminary scanning light in which multiple lights are bundled together, This includes controlling the direction of transmission of the scanning light to be transmitted by at least one light transmitting means based on which of the light receiving means received the preliminary scanning light, A method of optical space communication characterized by the following features.

6. A program for operating a computer as an optical space communication device according to any one of claims 1 to 3, characterized in that the computer functions as each of the means.

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