Wireless output device

Abstract

Provided is a wireless output device comprising: an optical circuit that is provided with a plurality of input ports and N output ports, causes each light wave incident on each input port to branch into N light waves, and causes output light waves, which are the light waves obtained by the branching, to be each output from a different output port; and an array antenna that has a circular array provided with N sets of photodiodes, on which the output light waves are incident, and antenna elements that are excited by the outputs of the photodiodes, wherein the output light waves output from the different output ports and a local wave, which is a light wave having a frequency f0, are incident on different photodiodes.

Description

Wireless output device

[0001] This invention relates to a wireless output device.

[0002] In recent years, wireless signal transmission technology using orbital angular momentum (OAM) has been investigated to improve transmission efficiency (see Non-Patent Documents 1 and 2).

[0003] Dong-Hun Kim, Jiro Hirokawa, and Makoto Ando. "One-body 2-D beam-switching Butler matrix with waveguide short-slot 2-plane couplers."IEICE Transactions on Electronics 100.10 (2017): 884-892.

[0004] Christos Tsokos, et al. "Analysis of a multibeam optical beamforming network based on Blass matrix architecture."Journal of Lightwave Technology 36.16 (2018): 3354-3372.

[0005] However, a problem arose with the large size of the circuit required to output wireless signals in multiple OAM modes.

[0006] In view of the above circumstances, the present invention aims to provide a technology for reducing the size of a circuit capable of outputting wireless signals in multiple types of OAM modes.

[0007] One aspect of the present invention is an optical circuit comprising a plurality of input ports and N (where N is an integer of 2 or more) output ports, wherein each light wave incident on each input port is branched into N light waves that satisfy a phase condition, and each output light wave obtained from the branching is output from a different output port; and an array antenna having a circular array comprising N sets of photodiodes into which the output light waves are incident and antenna elements excited by the output of the photodiodes, wherein different photodiodes receive output light waves output from different output ports and frequency f ０ A local wave, which is a light wave, is incident, and the phase condition is defined as follows: Of the N antenna elements located on the circumference, one predetermined antenna element is designated as the first element, and the antenna element closest to the nth element (n is an integer between 1 and N) along a predetermined direction either clockwise or counterclockwise along the circumference is designated as the (n+1)th element, and the phase difference between the nth light wave and the (n+1)th light wave is defined as the length of the arc on the circumference connecting the nth element and the (n+1)th element from the nth element in the predetermined direction is R ｎ , the length of one circumference is R ０ As, 2mπR ｎ / R ０ The wireless output device includes the condition that (m is the number of modes of the orbital angular momentum of the electromagnetic waves radiated from the circular array, and is a predetermined integer depending on the input port), wherein the nth light wave is one of N output light waves with the same input port, and is an output light wave output from the output port of the optical circuit that is connected to the nth element via the photodiode.

[0008] This invention makes it possible to reduce the size of a circuit capable of outputting wireless signals in multiple types of OAM modes.

[0009] An explanatory diagram illustrating the wireless output system of the embodiment. A diagram showing an example of the hardware configuration of the input generation device in the embodiment. A diagram showing an example of the spectrum incident on a photodiode in the embodiment. An explanatory diagram illustrating a first modified example of the wireless output system of the modified example. A diagram showing an example of the frequency spectrum of the composite wave incident on the optical circuit in the modified example. An explanatory diagram illustrating a second modified example of the wireless output system of the modified example. An explanatory diagram illustrating an example of the hardware configuration of the input generation device in the modified example. A diagram showing a first example of the frequency spectrum at the input port of the optical circuit of the modified example. A diagram showing a second example of the frequency spectrum at the input port of the optical circuit of the modified example. A first explanatory diagram illustrating an example of the effect caused by the incident on the input port of the optical circuit of the modified example. A second explanatory diagram illustrating an example of the effect caused by the incident on the input port of the optical circuit of the modified example. A diagram showing a first example of the arrangement of the circular array provided in the array antenna of the modified example. A diagram showing a second example of the arrangement of the circular array provided in the array antenna of the modified example.

[0010] (Embodiment) Figure 1 is an explanatory diagram illustrating a wireless output system 100 according to an embodiment. The wireless output system comprises a wireless output device 10 and an input generation device 20.

[0011] The wireless output device 10 comprises an array antenna 1, an optical circuit 2, and an optical splitter 3. The array antenna 1 comprises a circular array 110 in which N (N is an integer of 2 or more) antenna elements 11 are arranged in a circle at equal intervals, and N photodiodes 12. In the example in Figure 1, N = 8, and the array antenna 1 comprises eight antenna elements 11, from antenna element 11-1 to antenna element 11-8, and eight photodiodes 12, from photodiode 12-1 to photodiode 12-8.

[0012] Each antenna element 11 is connected to one photodiode 12, and different antenna elements 11 are not connected to the same photodiode 12. And the antenna element 11 is excited by the output of the photodiode 12. Therefore, it can be said that the circular array 110 is a circular array including N sets of a combination of the photodiode 12 and the antenna element 11 excited by the output of the photodiode 12.

[0013] The optical circuit 2 is an optical circuit including a plurality of input ports and N output ports. The optical circuit 2 performs matrix-like splitting, phase change, or multiplexing processing corresponding to matrix operations on the light waves incident on each input port, and outputs N light waves that satisfy the phase conditions respectively.

[0014] In the case of the example of FIG. 1, the optical circuit 2 includes eight input ports and eight output ports. In the case of the example of FIG. 1, light waves of eight different frequencies from f ０ to f ３ and from f －４ to f －１ are incident on the eight input ports. The optical circuit 2 is, for example, a Butler matrix. The optical circuit 2 may be, for example, a blass matrix. Regarding the phase condition, although the details will be described later because it is a condition related to the position of the antenna element connected to the output port via the photodiode, the phase condition is a condition for the radio wave of the OAM mode of the mode number m to be radiated from the circular array 110.

[0015] The light wave output from the output port (hereinafter referred to as "output light wave") is incident on the photodiode 12 connected to each output port. Output light waves output from different output ports are incident on different photodiodes 12. Therefore, the light wave output from one output port does not enter a plurality of photodiodes 12. Also, the light waves output from two output ports do not enter the same photodiode 12. Note that since the output light wave is the light wave output from the output port, it is the light wave output from the optical circuit 2.

[0016] Further, each photodiode 12 has a frequency f ＬＯA local wave, which is a light wave of a certain frequency, is incident. A photodiode outputs an electrical signal of the frequency difference when light waves of different frequencies are incident on it. Therefore, the frequency f ＬＯ When a local light wave, which is a light wave, and an output light wave are incident on it, an electrical signal with a frequency equal to the difference between the frequency of the output light wave and the frequency of the local light wave is output from the photodiode 12.

[0017] The optical splitter 3 splits the incoming light wave in the N direction. The frequency of the light wave incident on the optical splitter 3 is f Ｌ０ The light waves branched by the optical splitter 3 are received by the photodiode 12. The light waves branched in different directions are received by different photodiodes.

[0018] <Regarding Phase Conditions> As described above, each antenna element 11 of the circular array 110 is connected to a different photodiode 12, and these different photodiodes 12 are connected to different output ports of the optical circuit 2. Since the antenna elements 11 are antenna elements of a circular array, the antenna elements 11 are arranged on the circumference.

[0019] The phase of the signal that excites the antenna element 11 (output of the photodiode 12) depends on the position of the antenna element 11 on the circumference. For radio waves in OAM mode with mode m to be radiated, the relationship between the distance on the circumference from a predetermined position on the circular array 110 and the phase must be linear and change by 2 mπ per revolution. To reiterate, the phase condition is the condition for radio waves in OAM mode with mode m to be radiated.

[0020] Incidentally, the signal that excites the antenna element 11 is the output of the photodiode 12, and the phase difference between the signals output by different photodiodes 12 is equal to the phase difference of the light waves incident on each photodiode 12. Therefore, the phase condition can be defined by focusing on the antenna element 11.

[0021] Then, the phase condition will be described more specifically. Of the N antenna elements 11 located on the circumference, a predetermined one antenna element 11 is referred to as the first element, and the antenna element 11 closest to the nth element (n is an integer from 1 to N) along a predetermined one direction (hereinafter referred to as the "target direction") of the clockwise or counterclockwise circumference is referred to as the (n + 1)th element.

[0022] Using this terminology, in order for the radio wave of the OAM mode of mode number m to be radiated, the arc length of the circumference connecting the nth element and the (n + 1)th element from the nth element in the target direction is R ｎ , the length of one round of the circumference is R ０ Taking this as the case, the phase difference between the signal exciting the nth element and the signal exciting the (n + 1)th element needs to be 2mπR ｎ / R ０ Therefore.

[0023] Therefore, the phase condition includes the condition that the phase difference between the nth light wave and the (n + 1)th light wave is proportional to the arc length of the circumference connecting the nth element and the (n + 1)th element from the nth element in the target direction, where no other antenna element 11 exists on the arc. Here, the nth light wave is one of the N output light waves with the same input port, and is the output light wave output from the output port of the optical circuit 2 that is connected to the nth element via a photodiode among the output ports of the optical circuit 2.

[0024] Note that m is the mode number of the orbital angular momentum of the electromagnetic wave radiated from the circular array 110 and is an integer predetermined according to the input port. m may be a positive integer, zero, or a negative integer.

[0025] The input generation device 20 generates a signal to be input to the radio output device. More specifically, the signal output by the input generation device 20 is incident on any input port of the optical circuit 2. The signals output by the input generation device 20 are not incident on the same input port.

[0026] The input generation device 20 comprises a light wave generator 21, a local wave generator 22, and a control unit 23. The light wave generator 21 generates a modulated light wave. The local wave generator 22 generates a local wave. The control unit 23 controls the operation of the light wave generator 21 and the local wave generator 22.

[0027] An example of the hardware configuration of the input generation device 20 will be explained using Figure 2. Figure 2 is a diagram showing an example of the hardware configuration of the input generation device 20 in an embodiment. The input generation device 20 includes a control unit 23 which is a control unit equipped with a processor 91 such as a CPU, GPU or NPU connected by a bus and a memory 92, and executes a program. Upon execution of the program, the input generation device 20 functions as a device comprising an optical wave generator 21, a local wave generator 22, a control unit 23, an interface unit 24, a storage unit 25, and a first optical switch 26.

[0028] More specifically, the processor 91 reads the program stored in the storage unit 25 and stores the read program in the memory 92. By executing the program stored in the memory 92, the processor 91 functions as a device comprising a light wave generator 21, a local wave generator 22, a control unit 23, an interface unit 24, a storage unit 25, and a first optical switch 26.

[0029] The optical wave generator 21 outputs a modulated wave. The modulated wave output by the optical wave generator 21 is incident on the input port of the optical circuit 2. The optical wave generator 21 can have any configuration as long as it is capable of generating a modulated wave; for example, in the example shown in Figure 2, it comprises a first light source 211 and a modulator 212.

[0030] The first light source 211 is a light source. The first light source 211 is, for example, a laser. The light wave emitted from the first light source 211 is incident on the modulator 212. The modulator 212 is an external modulator that modulates the incident light wave with a modulation signal. The modulator 212 is, for example, an IQ modulator. Note that the light wave generator 21 does not necessarily need to include the first light source 211 and the modulator 212. For example, if the first light source 211 is a semiconductor laser that can be directly modulated, it is not necessary to include the modulator 212.

[0031] The local wave generator 22 includes a second light source 221 and generates local waves. The second light source 221 is a light source. For example, the local wave generator 22 includes an optical frequency comb generator, and passes only one peak of the comb-shaped spectrum generated by the optical frequency comb generator through a bandpass filter, outputting the passed light wave as a local wave.

[0032] The control unit 23 controls the operation of each functional unit of the input generation device 20. For example, the control unit 23 controls the operation of the optical wave generator 21. For example, the control unit 23 controls the operation of the local wave generator 22. For example, the control unit 23 controls the operation of the first optical switch 26. For example, the control unit 23 acquires the information stored in the memory unit 25. Specifically, the process of acquiring the information stored in the memory unit 25 is read.

[0033] The interface unit 24 includes a communication interface for connecting the input generation device 20 to an external device. The interface unit 24 communicates with the external device via wired or wireless connection.

[0034] The external device is, for example, the source device of the transmitted code sequence. The interface unit 24 acquires the transmitted code sequence by communicating with the source device of the transmitted code sequence. The transmitted code sequence is a signal that represents the information carried by the radio waves radiated by the array antenna 1. The modulated signal described above is a signal that represents the transmitted code sequence. Therefore, the light wave output by the light wave generator obtained by modulation with the modulated signal is a light wave that carries the information represented by the transmitted code sequence.

[0035] The interface unit 24 may include input devices such as a mouse, keyboard, or touch panel. The interface unit 24 may also be configured as an interface connecting these input devices to the input generation device 20. In this way, the input devices of the interface unit 24 receive various types of information to the input generation device 20 via wired or wireless connections. Note that the information does not necessarily have to be input to the communication interface of the interface unit 24; it may also be input to the input devices of the interface unit 24.

[0036] The interface unit 24 outputs various types of information, for example. The interface unit 24 is comprised of a display device such as a CRT (Cathode Ray Tube) display, a liquid crystal display, or an organic EL (Electro-Luminescence) display, as well as a speaker. The interface unit 24 may be configured as an interface for connecting these display devices or speakers to the input generation device 20. Therefore, the interface unit 24 may output information input to its input device as an image or sound, for example.

[0037] The storage unit 25 is configured using a computer-readable recording medium such as a magnetic hard disk drive or a semiconductor memory device. The storage unit 25 stores various information related to the input generation device 20. The storage unit 25 stores various information generated by the operation of the control unit 23, for example. The storage unit 25 may reside, for example, on the cloud.

[0038] The first optical switch 26 is an optical switch. The light wave output by the light wave generator 21 is incident on the first optical switch 26. The light wave that has passed through the first optical switch 26 is incident on the input port of the optical circuit 2. The first optical switch 26 controls the input port to which the incident light wave is incident. The control unit 23 can control the input port to which the light wave output by the light wave generator 21 is incident by controlling the operation of the first optical switch 26.

[0039] <Example of a spectrum incident on the photodiode 12> Figure 3 is a diagram showing an example of a spectrum incident on the photodiode 12 in the embodiment. In Figure 3, f ＯＡＭ This is the center frequency of the modulated wave. Figure 3 shows the frequency fL0 of the local wave and frequency f ＯＡＭ The difference is, f ＲＦ This demonstrates that, as described above, when light waves of different frequencies are incident on the photodiode 12, it outputs an electrical signal of the frequency difference. Therefore, in the example of Figure 3, the photodiode outputs an electrical signal of the frequency f ＲＦ It outputs a signal.

[0040] The wireless output system 100 configured in this way includes a wireless output device 10 comprising an optical circuit 2, a photodiode 12, and an antenna element 11. The optical circuit 2 satisfies a phase condition defined using an integer m, which is the number of modes of the orbital angular momentum of the electromagnetic waves radiated from the circular array 110 and is predetermined according to the input port. Therefore, the wireless output system 100 can switch the mode of the OAM radiated from the circular array 110 simply by switching the input port into which the light waves are incident. Consequently, the wireless output system 100 can reduce the size of the circuit capable of outputting wireless signals in multiple OAM modes.

[0041] Furthermore, the wireless output device 10 includes an optical circuit 2, a photodiode 12, and an antenna element 11. Therefore, the wireless output device 10 can switch the mode of the OAM radiated from the circular array 110 simply by switching the input port into which the light wave is incident. Consequently, the wireless output device 10 can reduce the size of the circuit that can output wireless signals in multiple OAM modes.

[0042] Although the explanation has been given using the example where the first optical switch 26 controls which input port of the optical circuit 2 receives the light wave output from the light wave generator 21, the control unit 23 does not necessarily have to control the first optical switch 26. For example, the operation of the first optical switch 26 may be controlled manually, and the input port to which the light wave is incident may be switched.

[0043] (Modified Version) <First Modified Version of the Wireless Output System> Figure 4 is an explanatory diagram illustrating a modified wireless output system 100a. Hereafter, components having the same functions as the wireless output system 100 will be denoted by the same reference numerals as in Figure 1, and their explanation will be omitted. The wireless output system 100a differs from the wireless output system 100 in that it includes a wireless output device 10a instead of a wireless output device 10.

[0044] The wireless output device 10a differs from the wireless output device 10a in that it includes an optical circuit 2a instead of the optical circuit 2. The optical circuit 2a has a center frequency (f) at least one of its input ports. ＬＯ +f ＲＦ) the modulated wave and the center frequency (f ＬＯ -f ＲＦ It differs from optical circuit 2 in that a composite wave with the modulated wave is incident. ＲＦ It is a real number.

[0045] Figure 5 shows an example of the frequency spectrum of the composite wave incident on the optical circuit 2a in a modified example. ＋ and f － Regarding this, f ＋ = (f ＬＯ +f ＲＦ ) and f － = (f ＬＯ -f ＲＦ )

[0046] In fact, when the frequency of the modulated wave is on the positive side compared to the frequency of the local wave, radio waves of the orbital angular momentum mode where m is a positive value are radiated from the antenna element 11. On the other hand, when the frequency of the modulated wave is on the negative side compared to the frequency of the local wave, radio waves of the orbital angular momentum mode where m is a negative value are radiated from the antenna element 11.

[0047] Therefore, when the above composite wave is input to one input port, two types of radio waves, one with positive and one with negative orbital angular momentum, are simultaneously radiated. Consequently, even with fewer input ports than optical circuit 2, optical circuit 2a can radiate radio waves in M ​​types of orbital angular momentum modes (where M is a predetermined integer of 2 or more). Consequently, the radio output device 10a can have an even smaller circuit size than radio output device 10. Consequently, the radio output system 100a can have an even smaller circuit size than radio output system 100.

[0048] <Second Modification of Wireless Output System> Figure 6 is an explanatory diagram illustrating a modified wireless output system 100b. Hereafter, components having the same functions as wireless output systems 100 or 100a will be denoted by the same reference numerals as in Figures 1 or 4, and their descriptions will be omitted. Wireless output system 100b differs from wireless output system 100a in that it includes a wireless output device 10b and an input generation device 20b instead of wireless output device 10a.

[0049] The wireless output device 10b differs from the optical circuit 2a in that it has an optical circuit 2b instead and does not have an optical splitter 3. The optical circuit 2b differs from the optical circuit 2a in that the local wave is incident on the input port.

[0050] In the example in Figure 6, the input ports of the optical circuit 2b are, in order from left to right on the page of Figure 6, frequency f ０ Modulated wave and frequency f ＬＯ A composite wave with the local wave, frequency f ＋１ Modulated wave and frequency f －１ The combined wave of the modulated wave and the combined wave, frequency f ＋２ Modulated wave and frequency f －２ The combined wave of the modulated wave and the combined wave, frequency f ＋３ Modulated wave and frequency f －３ The combined wave of the modulated wave and the combined wave, frequency f ＋４ Modulated wave and frequency f －４ This indicates that a composite wave of the modulated wave and the incident wave is present.

[0051] Figure 7 is an explanatory diagram illustrating an example of the hardware configuration of the input generation device 20b in a modified example. Hereafter, components having the same functions as the input generation device 20 will be denoted by the same reference numerals as in Figure 2, and their explanation will be omitted. The input generation device 20b differs from the input generation device 20 in that it further includes a second optical switch 27.

[0052] The second optical switch 27 is an optical switch. The light wave output by the local wave generator 22 (i.e., the local wave) is incident on the second optical switch 27. The light wave that has passed through the second optical switch 27 is incident on the input port of the optical circuit 2. The second optical switch 27 controls the input port to which the incident light wave is incident. The control unit 23 can control the operation of the second optical switch 27. By controlling the operation of the second optical switch 27, the control unit 23 can control the input port to which the light wave output by the local wave generator 22 is incident.

[0053] Figure 8 shows a first example of the frequency spectrum at the input port of the modified optical circuit 2b. Figure 8 shows the local wave and the center frequency f ０ This shows an example of the frequency spectrum at the input port to which the modulated wave is input.

[0054] Figure 9 shows a second example of the frequency spectrum at the input port of the modified optical circuit 2b. Figure 9 shows the center frequency f ＋ｋ Modulated wave and center frequency f (k is 1-4) －ｋ An example of the frequency spectrum of the composite wave with the modulated wave is shown.

[0055] Figure 10 is a first explanatory diagram illustrating an example of the effect caused by the incidence of a local wave on the input port of the optical circuit 2b in a modified example. The horizontal axis of Figure 10 shows the index of the antenna elements. More specifically, the horizontal axis of Figure 10 shows the identifier n when the antenna elements 11 are individually identified as antenna element 11-1, antenna element 11-2, ..., antenna element 11-n, ..., antenna element 11-N.

[0056] Considering the phase conditions, the mode of the orbital angular momentum of the radio signal generated from the light wave incident on that input port is determined by the input port. Therefore, below, an input port from which a radio signal of mode m = Q is generated will be referred to as a mode Q port.

[0057] Figure 10 shows the radio phase at each antenna element when the modulated wave is incident on a Mode 2 port, and the radio phase at each antenna element when the local wave is incident on a Mode 0 port.

[0058] In the example shown in Figure 10, the phase of the upper sideband radio is the phase obtained by subtracting the phase of the local wave from the phase of the modulated wave, so the mode of the radio's orbital angular momentum is the mode m = +2. On the other hand, the phase of the lower sideband radio is the phase obtained by subtracting the phase of the modulated wave from the phase of the local wave, so the mode of the radio's orbital angular momentum is the mode m = -2.

[0059] Figure 11 is a second explanatory diagram illustrating an example of the effect caused by the incidence of a local wave on the input port of the optical circuit 2b in a modified example. The horizontal axis of Figure 11, as in Figure 10, shows the index of the antenna element.

[0060] Figure 11 shows the radio phase at each antenna element when the modulated wave is incident on a Mode 2 port, and the radio phase at each antenna element when the local wave is incident on a Mode 1 port.

[0061] In the example shown in Figure 11, the phase of the upper sideband radio is the phase obtained by subtracting the phase of the local wave from the phase of the modulated wave, so the mode of the radio's orbital angular momentum is the mode m = +1. On the other hand, the phase of the lower sideband radio is the phase obtained by subtracting the phase of the modulated wave from the phase of the local wave, so the mode of the radio's orbital angular momentum is the mode m = -1.

[0062] Thus, since the wireless output device 10b is equipped with an optical circuit 2b, it can generate wireless signals of modes m = ±(Q - T) (where T is an integer) from a modulated wave incident on a port of mode ±Q. Similarly, since the wireless output system 100b is equipped with the wireless output device 10b, it can generate wireless signals of modes m = ±(Q - T) (where T is an integer) from a modulated wave incident on a port of mode ±Q.

[0063] Although the explanation has been given using the example where the second optical switch 27 controls which input port of the optical circuit 2b receives the light wave output by the local wave generator 22, the control of the second optical switch 27 does not necessarily have to be performed by the control unit 23. For example, the operation of the second optical switch 27 may be controlled manually, and the input port to which the light wave is incident may be switched.

[0064] Furthermore, if the antenna elements 11 on the circular array 110 are positioned at equal intervals, the difference between the nth (where n is an integer between 1 and N) smallest output light wave and the (n+1)th smallest output light wave, given by the optical circuit 2, may be 2mπ / N.

[0065] Furthermore, the array antenna 1 does not necessarily have to consist of only one circular array 110, but may consist of multiple circular arrays 110. For example, the array antenna 1 may consist of multiple circular arrays 110 having the same center and the same radius, arranged so that the positions of the antenna elements 1 do not overlap. For example, the array antenna 1 may consist of multiple circular arrays 110 having the same center but different radii.

[0066] Figure 12 shows a first example of the arrangement of circular arrays 110 in an array antenna 1 in a modified example. Figure 12 shows two circular arrays 110, a first circular array and a second circular array. An array antenna having the first circular array and the second circular array in the arrangement shown in Figure 12 is an example of an array antenna 1 that has multiple circular arrays 110 with the same center and radius, arranged so that the positions of the antenna elements 1 do not overlap.

[0067] The first circular array is a circular array composed of antenna elements 11a-1, 11a-2, 11a-3, 11a-4, 11a-5, 11a-6, 11a-7, and 11a-8 in the example shown in Figure 12.

[0068] The second circular array is a circular array composed of antenna elements 11b-1, 11b-2, 11b-3, 11b-4, 11b-5, 11b-6, 11b-7, and 11b-8 in the example shown in Figure 12.

[0069] Figure 13 shows a second example of the arrangement of the circular arrays 110 in the array antenna 1 in a modified example. Figure 13 shows two circular arrays 110, a third circular array and a fourth circular array. The array antenna having the third circular array and the fourth circular array in the arrangement shown in Figure 13 is an example of an array antenna 1 having multiple circular arrays 110 that have the same center but different radii.

[0070] The third circular array is a circular array composed of antenna elements 11c-1, 11c-2, 11c-3, 11c-4, 11c-5, 11c-6, 11c-7, and 11c-8 in the example shown in Figure 13.

[0071] The fourth circular array is a circular array composed of antenna elements 11d-1, 11d-2, 11d-3, 11d-4, 11d-5, 11d-6, 11d-7, and 11d-8 in the example shown in Figure 13.

[0072] Furthermore, all or part of the functions of each of the wireless output system 100, wireless output system 100a, wireless output system 100b, wireless output device 10, wireless output device 10a, and wireless output device 10b may be implemented using hardware such as ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array). The program may be recorded on a computer-readable recording medium. Computer-readable recording media include, for example, portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. The program may also be transmitted via a telecommunications line.

[0073] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0074] 100, 100a, 100b... Wireless output system, 10, 10a, 10b... Wireless output device, 1... Array antenna, 110... Circular array, 11... Antenna element, 12... Photodiode, 2, 2a, 2b... Optical circuit, 3... Optical splitter, 20, 20b... Input generation device, 21... Optical wave generator, 22... Local wave generator, 23... Control unit, 24... Interface unit, 25... Memory unit, 26... First optical switch, 27... Second optical switch, 211... First light source, 212... Modulator, 221... Second light source

Claims

1. An optical circuit comprising a plurality of input ports and N (N is an integer of 2 or more) output ports, wherein each light wave incident on each input port is branched into N light waves that satisfy a phase condition, and each output light wave obtained from the branching is output from a different output port; and an array antenna having a circular array comprising N sets of photodiodes into which the output light waves are incident and antenna elements excited by the output of the photodiodes, wherein different photodiodes receive output light waves output from different output ports and frequency f ０ A local wave, which is a light wave, is incident, and the phase condition is defined as follows: Of the N antenna elements located on the circumference, one predetermined antenna element is designated as the first element, and the antenna element closest to the nth element (n is an integer between 1 and N) along a predetermined direction either clockwise or counterclockwise along the circumference is designated as the (n+1)th element, and the phase difference between the nth light wave and the (n+1)th light wave is defined as the length of the arc on the circumference connecting the nth element and the (n+1)th element from the nth element in the predetermined direction is R ｎ , the length of one circumference is R ０ As, 2mπR ｎ / R ０ A wireless output device comprising the condition that (m is the number of modes of the orbital angular momentum of the electromagnetic waves radiated from the circular array, and is a predetermined integer depending on the input port), wherein the nth light wave is one of N output light waves having the same input port, and is an output light wave output from an output port of the optical circuit that is connected to the nth element via the photodiode.

2. One of the plurality of the input ports has an incident composite wave of a modulated wave with a center frequency (f ＬＯ + f ＲＦ ), and a modulated wave with a center frequency (f ＬＯ - f ＲＦ ). The wireless output device according to claim 1.

3. The wireless output device according to claim 1, wherein the local wave is incident on the input port.

4. The wireless output device according to any one of claims 1 to 3, wherein the array antenna comprises a plurality of circular arrays.

Images