System, transmission device, and reception device

Abstract

A system comprising a transmission device (10) that transmits a beam and a reception device (20) that receives the beam, wherein the transmission device (10) is provided with a beam shaper (12) that shapes, for communication, a central portion of the beam output from a laser and shapes, for power supply, a portion around the central portion, and the reception device (20) is provided with a panel (23) that receives the first beam shaped for communication and the second beam shaped for power supply.

Description

System, Transmitting Device, and Receiving Device

[0001] The present invention relates to technologies of optical wireless power supply and optical wireless communication.

[0002] Optical wireless power supply is a technology that can supply power to devices and equipment without wiring. This technology is expected to be used for power supply to moving objects such as drones and for power supply to remote areas such as remote islands. Also, compared with microwaves, it has the advantages of enabling the system to be longer and smaller in size and not causing electromagnetic interference.

[0003] On the other hand, wireless communication using light has attracted attention rather than radio wave communication because of the advantages of low latency, high speed, large capacity, and confidentiality.

[0004] Taking advantage of the respective merits of optical wireless power supply and optical wireless communication, the demand for a system that performs optical wireless power supply and optical wireless communication simultaneously is increasing. As a conventional technology for a system that performs optical wireless power supply and optical wireless communication simultaneously, for example, the technology disclosed in Non-Patent Document 1 is known. According to the conventional technology disclosed in Non-Patent Document 1, it is possible to supply power to electric devices such as UAVs (unmanned aerial vehicles), smartphones, and PCs, and to perform communication using light.

[0005] In the technology disclosed in Non-Patent Document 1, the beam from the transmitting side is split into two at the receiving side, and the light is received by the photoelectric conversion element for power supply and the follower for communication.

[0006] Y. Bai, Q. Liu, R. Chen, Q. Zhang and W. Wang, "Long-Range Optical Wireless Information and Power Transfer," in IEEE Internet of Things Journal, vol. 10, no. 2, pp. 1617-1627, 15 Jan.15, 2023

[0007] Not limited to a system that performs optical wireless power supply and optical wireless communication simultaneously, it is desirable for the system to be miniaturized. Also, if the wavelength is changed for communication and power supply, the same optical configuration cannot be achieved for both transmission and reception, so it is necessary to use the same wavelength for the system.

[0008] Furthermore, because the optimal beam differs for power supply and communication, systems that split the same beam into two for reception, as in conventional technology, are likely to experience a decrease in power supply efficiency and communication quality. Additionally, splitting the beam at the receiving end and then reshaping it into the optimal beam would complicate and increase the system's size.

[0009] Regarding the fact that the optimal beam differs for power supply and communication, during power supply, it is desirable to uniformly irradiate the photoelectric conversion panel, which consists of arranged photoelectric conversion elements, with the beam in order to increase efficiency. On the other hand, during communication, a beam that is multiplexable and resistant to atmospheric disturbances is required from the standpoint of information capacity and quality. Laguerre-Gaussian beams (LG beams) are among the most promising beams to be used during communication.

[0010] This invention has been made in view of the above points, and aims to provide a technology for improving power supply efficiency and communication quality in a system that performs optical wireless power supply and optical wireless communication simultaneously, while maintaining a compact system.

[0011] According to the disclosed technology, a system is provided comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, wherein the transmitting device includes a beam shaper for shaping the central part of a beam output from a laser for communication and the surrounding part for power supply, and the receiving device includes a panel for receiving the first beam shaped for communication and the second beam shaped for power supply.

[0012] According to the disclosed technology, a technology is provided to improve power supply efficiency and communication quality in a system that performs optical wireless power transfer and optical wireless communication simultaneously, while maintaining a compact system size.

[0013] This is a diagram illustrating the outline of the technology according to an embodiment of the present invention. This is a diagram illustrating the outline of the technology according to an embodiment of the present invention. This is a system configuration diagram of Example 1. This is a configuration diagram of the transmitter 10 of Example 2. This is a configuration diagram of the receiver 20 of Example 3. This is a system configuration diagram of Example 4-1. This is a system configuration diagram of Example 4-2. This is a diagram showing the intensity distribution before beam shaping. This is a diagram showing the phase distribution given by beam shaping. This is a diagram showing the intensity distribution after propagation. This is a diagram showing the cross-section at y=0 with respect to the intensity distribution after propagation.

[0014] Hereinafter, embodiments of the present invention (this embodiment) will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the embodiments described below.

[0015] (Outline of the Embodiment) An overview of the technology according to this embodiment will be described with reference to Figures 1 and 2.

[0016] As shown in Figure 1, the system according to this embodiment is equipped with a beam shaper 12 on the transmitting side. The beam shaper 12 takes a Gaussian beam as input and shapes the beam so that the central part is for communication and the surrounding part is for power supply before outputting it.

[0017] As shown in Figure 2, the receiving side is equipped with a communication and power supply integrated panel 23 in which the central part of the photoelectric conversion panel 21 (PV panel 21) is replaced with a communication photodiode 22 (PD 22). In panel 23, the communication beam shaped by the beam shaper 12 is incident on the PD 22, and the power supply beam shaped by the beam shaper 12 is incident on the PV panel 21.

[0018] If the power supply beam enters the communication PD22, it will create noise and reduce the signal-to-noise ratio. Therefore, only the communication beam is directed at the PD22, and the surrounding area is shaped by the beam shaper 12 so that the communication beam and the power supply beam overlap and become flat, thereby improving power supply efficiency.

[0019] Examples 1 to 4 of the following are more specific examples of system configurations.

[0020] (Example 1) Figure 3 shows an example of the overall system configuration in Example 1. As shown in Figure 3, this system has a transmitting device 10 and a receiving device 20.

[0021] The transmitting device 10 has a laser 11, which is a light source, and a beam shaper 12. The receiving device 20 has a panel 23. The beam shaper 12 is a device that can modulate the phase and intensity of light. The panel 23 is a communication and power supply integrated panel 23 in which a PD 22 is embedded in the center of the PV panel 21.

[0022] In the system shown in Figure 3, after a beam is emitted from the laser 11, the beam shaper 12 shapes the beam into a desired form. The desired form is such that, as explained with reference to Figures 1 and 2, only the communication beam is irradiated to the center (PD 22), and the surrounding area is made flat with the communication beam and the power supply beam overlapping to improve power supply efficiency.

[0023] The beam shaping device 12 can be any variable beam shaping device; for example, a spatial light modulator (SLM) or a variable mirror (DM) can be used as the beam shaping device 12.

[0024] If a non-communication beam is shone onto the PD22, which is used for communication, it will generate noise and reduce the signal-to-noise ratio. Therefore, the system should be designed so that only communication beams are shone onto the PD22. For example, the communication beam (LG beam, etc.) can be shaped at the center, and the ring-shaped beam (Bessel beam, etc.) can be shaped on the outside.

[0025] (Example 2) Next, Example 2 will be described. In Example 2, a different configuration of the transmitting device 10 from that of Example 1 will be described. The receiving device 20 in Example 2 may be the same as that in Example 1.

[0026] Figure 4 shows an example of the configuration of the transmitting device 10 in Embodiment 2. As shown in Figure 4, the transmitting device 10 in Embodiment 2 comprises a plurality of lasers 11, a plurality of beam shapers 12, and a plurality of mirrors 13.

[0027] In other words, as shown in Figure 4, the transmitting device 10 in Embodiment 2 has multiple sets of "laser 11, beam shaping device 12, and mirror 13". Note that the mirror 13 is a half-mirror.

[0028] Figure 4 shows, as examples, "laser 11-1, beam shaper 12-1, mirror 13-1" and "laser 11-2, beam shaper 12-2, mirror 13-2". Hereafter, the set of "laser 11, beam shaper 12, and mirror 13" will be referred to as "laser 11-n, beam shaper 12-n, mirror 13-n", where n is an integer greater than or equal to 1.

[0029] In the configuration of Example 2, the beam shaper 12-n shapes the central part of the beam output from the laser 11-n (the communication beam) into an LG beam.

[0030] The beam shaper 12-n shapes the outer edge of the beam output from the laser 11-n into a Bessel beam. As already explained, it shapes the beam so that it does not enter the central PD22.

[0031] In Embodiment 2, spatial mode multiplexing communication is performed. For this purpose, multiple modes are prepared for the central LG beam, and multiple mirrors 13 are used to superimpose the LG beams of multiple modes.

[0032] For example, in the example shown in Figure 4, a mode 1 LG beam is output from beam shaper 12-1, and a mode 2 LG beam is output from beam shaper 12-2. The mode 2 LG beam is reflected by mirror 13-2 and incident on mirror 13-1. Mirror 13-1 transmits the mode 1 LG beam output from beam shaper 12-1 and reflects the mode 2 LG beam towards the receiving device 20. As a result, a beam in which the mode 1 LG beam and the mode 2 LG beam are superimposed (multiplexed) is incident on the PD 22 of the receiving device 20. Similarly, the surrounding Bessel beam is reflected by mirror 13 and incident on the PV panel 21 of the receiving device 20.

[0033] The parameters for beam shaping are not limited to specific parameters, but an example is as follows:

[0034] - Input beam diameter: cm (total width of 1 / e^2) - Center LG beam diameter: cm - Focal length of Bessel beam: 50 m Note that in Example 2 (and Example 1), the modulation of the communication may be applied to the laser output amplitude, or the amplitude may be modulated by the beam shaper 12.

[0035] (Example 3) Next, Example 3 will be described. Example 3 shows a specific configuration example of the receiving device 20. The transmitting device 10 in Example 3 may be the same as in Example 1, or the same as in Example 2.

[0036] Figure 5 shows an example of the configuration of the receiving device 20 in Embodiment 3. The receiving device 20 has a panel 23. The panel 23 has a configuration in which a PD 22 for communication is placed in the center of a PV panel 21 consisting of multiple PV cells.

[0037] As an example, panel 23 consists of 24 cells, each 2 cm square, connected in series. This corresponds to the beam shaping parameters described in Example 2.

[0038] (Example 4) Example 4 is an example of variations in the location where modulation is performed. Examples 4-1 and 4-2 will be described in Example 4.

[0039] <Example 4-1: Simultaneous beam shaping and communication modulation> Figure 6 shows an example of a configuration when beam shaping and communication modulation are performed simultaneously. The transmitting device 10 shown in Figure 6 has lasers 11-1, 11-2, 11-3, ..., shaping and modulation units 14-1, 14-2, 14-3, ..., and a coupling unit 15.

[0040] Each shaping / modulation unit 14, for example, is equipped with a modulation function within the beam shaper 12. The coupling unit 15 is a functional unit that combines the multiple beams output from the shaping / modulation units 14-1, 14-2, 14-3, ..., and has a configuration that includes, for example, multiple mirrors 13 as described in Embodiment 2.

[0041] In Example 4-1, the system may be equipped with one laser 11 and one shaping / modulation unit 14, but without a coupling unit 15.

[0042] <Example 4-2: Applying Modulation to Laser 11 Itself>FIG. 7 shows a configuration example in the case of applying modulation for communication to laser 11 itself. The transmission device 10 shown in FIG. 7 includes modulation units 16-1, 16-2, 16-3, ..., lasers 11-1, 11-2, 11-3, ..., shaping units 17-1, 17-2, 17-3, ..., and a combining unit 15.

[0043] Each modulation unit 16 transmits a modulation signal to laser 11, so that laser 11 modulates the output beam. Each shaping unit 17 is, for example, a beam shaper 12. The combining unit 15 is a functional unit that combines a plurality of beams output from the shaping units 17-1, 17-2, 17-3, ..., and has, for example, a configuration including a plurality of mirrors 13 described in Example 2.

[0044] Note that in Example 4-2, it may be configured to include one modulation unit 16, one laser 11, and one shaping unit 17, and not include the combining unit 15.

[0045] (Example 5) Example 5 is an example regarding the beam pattern. Example 5 is an example with the configuration shown in FIG. 3, for example.

[0046] Specifically, in Example 5, a calculation example of one mode of the LG beam is shown. The radial mode of the LG beam was designed to be 7, and the angular mode was designed to be 3. The propagation distance was set to 100 m. Regarding the radial mode and the angular mode, they are described in, for example, the reference document "Characteristic Evaluation of an Optical Wireless Communication System Applying Laguerre-Gaussian Beams, Transactions of the Institute of Electronics, Information and Communication Engineers B Vol. J102-B No. 2 pp. 80-89".

[0047] FIG. 8 shows the intensity distribution before beam shaping. FIG. 9 shows the phase distribution given by beam shaping. As already described, the central part is shaped into an LG beam effective for communication, and the outside of the central part is shaped into a Bessel beam.

[0048] FIG. 10 shows the intensity distribution after propagation. The LG beam and the Bessel beam overlap, and the overall intensity is flat.

[0049] Figure 11 shows the cross-section at y=0 for the intensity distribution after propagation. As shown near x=0, the Bessel beam, which is not related to communication, is not incident on PD22, and only the LG beam is incident on it.

[0050] (Effects of the Embodiment) As described above, the technology described in this embodiment makes it possible to shape a beam that is optimal for optical wireless power transfer and optical communication while maintaining a compact system, thereby improving power transfer efficiency and communication quality.

[0051] The following additional information is disclosed regarding the embodiments described above.

[0052] <Notes> (Note 1) A system comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, wherein the transmitting device comprises a beam shaper for shaping the central part of a beam output from a laser for communication and shaping the portion surrounding the central part for power supply, and the receiving device comprises a panel for receiving the first beam shaped for communication and the second beam shaped for power supply. (Note 2) The system according to Note 1, wherein the panel is a panel in which the central part of a photoelectric conversion panel is replaced with a communication photodiode. (Note 3) The system according to Note 1, wherein the first beam is an LG (Laguerre-Gaussian) beam and the second beam is a Bessel beam. (Note 4) The system according to Note 1, wherein the transmitting device comprises a plurality of beam shapers and a coupling unit for coupling a plurality of beams output from the plurality of beam shapers. (Note 5) A transmitting device used in a system comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, the transmitting device comprising a beam shaper for shaping the central part of a beam output from a laser for communication and shaping the portion surrounding the central part for power supply. (Note 6) A receiving device used in a system comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, the receiving device comprising a panel in which the central part of a photoelectric conversion panel is replaced with a communication photodiode. (Note 7) The receiving device according to Note 6, wherein the communication photodiode receives a communication beam shaped by the transmitting device, and the photoelectric conversion panel surrounding the communication photodiode receives a power supply beam shaped by the transmitting device.

[0053] Although this embodiment has been described above, the present invention is not limited to this specific embodiment, and various modifications and changes are possible within the scope of the gist of the invention as described in the claims.

[0054] 10 Transmitter 11 Laser 12 Beam shaper 13 Mirror 14 Shaping / modulation unit 15 Coupling unit 16 Modulation unit 17 Shaping unit 20 Receiver 21 PV panel 22 PD 23 Panel

Claims

1. A system comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, wherein the transmitting device includes a beam shaper for shaping the central part of a beam output from a laser for communication and the surrounding part for power supply, and the receiving device includes a panel for receiving the first beam shaped for communication and the second beam shaped for power supply.

2. The system according to claim 1, wherein the panel is a panel in which the central part of a photoelectric conversion panel is replaced with a communication photodiode.

3. The system according to claim 1, wherein the first beam is an LG (Laguerre-Gaussian) beam and the second beam is a Bessel beam.

4. The system according to claim 1, wherein the transmitting device comprises a plurality of beam shapers and a coupling unit that combines a plurality of beams output from the plurality of beam shapers.

5. A transmitting device used in a system comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, the transmitting device comprising a beam shaper for shaping the central part of a beam output from a laser for communication and shaping the portion surrounding the central part for power supply.

6. A receiving device used in a system comprising a transmitting device for transmitting a beam and a receiving device for receiving the beam, the receiving device comprising a panel in which the central part of a photoelectric conversion panel is replaced with a communication photodiode.

7. The receiving device according to claim 6, wherein the communication photodiode receives a communication beam shaped by the transmitting device, and the photoelectric conversion panel surrounding the communication photodiode receives a power supply beam shaped by the transmitting device.

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