Transmission directivity control device and transmission directivity control method

Abstract

A transmission directivity control device according to the present invention comprises a first axis phase ramp application unit that applies a phase ramp that is a phase ramp for a first axis of a space and varies in accordance with control details to an inputted optical signal and outputs the optical signal and a second axis phase ramp application unit that applies a phase ramp that is a phase ramp for a second axis that is orthogonal to the first axis and varies in accordance with the wavelength of an optical signal inputted from the first axis phase ramp application unit to the optical signal inputted from the first axis phase ramp application unit.

Description

Technical Field

[0001] The present invention relates to a transmission directivity control device and a transmission directivity control method.

Background Art

[0002] As a means to achieve high-speed and high-capacity wireless communication, the utilization of high-frequency bands above the millimeter-wave band has been progressing. Since the spatial propagation loss of radio waves increases as the frequency increases (for example, the free-space propagation loss increases in proportion to the square of the frequency), antennas with high gains are often used in such high-frequency bands. Since high-gain antennas always have high directivity, it is necessary to align the direction of the beam with the communication partner of the wireless communication. When the direction of the communication partner is dynamic, a means to dynamically control the direction of the beam, that is, the application of beam steering, becomes essential. Also, not limited to wireless communication, for example, in applications such as radar, imaging, and wireless power transmission, the implementation of beam steering in antennas is required.

[0003] As means for beam steering, a method of mechanically controlling the azimuth of an antenna, a method of refracting or reflecting radio waves radiated from an antenna with a movable lens or mirror, etc. have been devised and used. Also, since it does not use mechanical movable parts, phased array antennas, which have high durability and followability of movement and are suitable for miniaturization and weight reduction of antennas, are often used.

[0004] A phased array antenna electronically performs beam steering by controlling the phase and amplitude of the RF (Radio Frequency) signals supplied to each antenna element (hereinafter, the control of the phase and amplitude is called weighting) using means such as variable delay circuits, variable attenuator circuits, and digital signal processing connected to a plurality of antenna elements arranged on a line or on a plane.

[0005] In fifth-generation mobile communication systems that use the millimeter-wave band, millimeter-wave band wireless local area network (LAN) systems, etc., phased array antennas of the type that perform weighting with analog circuits are often used.

[0006] In many wireless communication systems, the range where the communication partner exists changes not in a two-dimensional plane but in a three-dimensional space. Therefore, for example, beam steering in two axes such as azimuth and elevation angle is necessary. For this reason, the phased array antenna requires weighting for performing two-dimensional beam steering using a two-dimensional array antenna in which antenna elements are arranged in a planar manner.

[0007] For example, Non-Patent Document 1 discloses a 256-element phased array antenna used for a base station for fifth-generation mobile communication in the 28 GHz band. For example, when the radio frequency becomes about 10 times, such as 300 GHz, the propagation loss in free space becomes 100 times, and it is considered that tens of thousands of antenna elements are required.

[0008] When the radio frequency is 300 GHz, since the free space wavelength is 1 mm, it is common to set the interval between antenna elements to half of the wavelength, that is, 0.5 mm. At this time, it is difficult to install a phase shifter circuit in the vicinity of the antenna element at an interval equivalent to the interval between the antenna elements. Also, in order to configure a circuit (multi-beam forming circuit) that forms a plurality of beams, the same number of phase shifters as the number of beams must be arranged in parallel, which is assumed to be even more difficult.

[0009] Instead of implementing a phase shifter circuit according to the number of antenna elements, there is a method of using a passive circuit with a fixed phase shift amount and switching its input terminals for use. For example, Non-Patent Document 2 discloses a method of performing two-dimensional beam steering using a passive circuit. However, it is necessary to assemble the circuit three-dimensionally, and since it is necessary to be composed of waveguides for implementation in a high-frequency band, mass production is difficult, and it is also difficult to cope with a large number of elements.

[0010] Non-Patent Document 3 proposes a method of converting a signal into light and performing weighting using an optical circuit. As a method of performing weighting using an optical circuit, Patent Document 1 discloses a three-dimensional optical circuit that performs two-dimensional beam steering using a wavelength dispersion line. Non-Patent Document 4 discloses a method using a loop configuration that repeatedly reuses a phase shifter while converting an optical wavelength. Non-Patent Document 5 combines a planar phase shift circuit and an FBG (fiber bragg gratings) reflection line with different delay times depending on the optical wavelength, and in addition to one-dimensional (in one plane) beam steering performed by the planar phase shift circuit, beam steering in a plane orthogonal to the said plane performed by the FBG reflection line is enabled, and means for implementing two-dimensional beam steering is disclosed. Patent Document 2 discloses a multi-beam forming means using wavelength multiplexing.

[0011] However, in the above-disclosed devices and methods, there are drawbacks such as difficulty in manufacturing a three-dimensional structure as the frequency increases and an extremely large number of parts.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0013]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0014] An object of the present invention is to provide a transmission directivity control device that can be created more simply.

Means for Solving the Problems

[0015] One aspect of the present invention is a first-axis phase gradient imparting unit that imparts a phase gradient on a first axis, which is a certain axis in space, to an input optical signal, and outputs the optical signal with a phase gradient different according to the control content; and a second-axis phase gradient imparting unit that imparts a phase gradient on a second axis orthogonal to the first axis to the optical signal input from the first-axis phase gradient imparting unit, and outputs the optical signal with a phase gradient different according to the wavelength of the optical signal input from the first-axis phase gradient imparting unit. The transmission directivity control device includes the first-axis phase gradient imparting unit and the second-axis phase gradient imparting unit.

[0016] One aspect of the present invention is a first-axis phase gradient imparting step of imparting a phase gradient on a first axis, which is a certain axis in space, to an input optical signal, and outputting the optical signal with a phase gradient different based on the control content; and a second-axis phase gradient imparting step of imparting a phase gradient on a second axis orthogonal to the first axis to the optical signal with the phase gradient imparted on the first axis, and outputting the optical signal with a phase gradient different according to the wavelength of the optical signal. The transmission directivity control method includes the first-axis phase gradient imparting step and the second-axis phase gradient imparting step.

Effects of the Invention

[0017] According to the present invention, a transmission directivity control device can be provided more simply.

Brief Description of the Drawings

[0018]

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Figure 9

[0019] Hereinafter, embodiments of the present invention 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 following embodiments.

[0020] FIG. 1 is a diagram showing a configuration example of the transmission directivity control device 1.

[0021] The transmission directivity control device 1 includes a light source 11, an optical modulator 12, a control unit 13, a first-axis phase tilt imparting unit 14, a second-axis phase tilt imparting unit 15, and a two-dimensional array antenna 16.

[0022] The light source 11 outputs light to the optical modulator 12. The light source 11 is a wavelength-variable light source. The optical modulator 12 generates an optical signal by modulating the input light. The optical modulator 12 generates an optical signal, for example, by modulating the light output from the light source with a transmission signal.

[0023] The control unit 13 controls the light source 11 and the first-axis phase tilt imparting unit 14. The control unit 13 controls the wavelength of the light output from the light source 11 to control the wavelength of the optical signal input to the first-axis phase tilt imparting unit 14.

[0024] The first-axis phase tilt imparting unit 14 imparts a phase tilt on the first axis, which is a certain axis in space, to the input optical signal. The first-axis phase tilt imparting unit 14 outputs the optical signal with the imparted phase tilt from any one of the plurality of output terminals to the second-axis phase tilt imparting unit 15. The first-axis phase tilt imparting unit 14 imparts different phases to the optical signal according to conditions. The first-axis phase tilt imparting unit 14 imparts, for example, different phases to the optical signal according to the wavelength of the optical signal. The first-axis phase tilt imparting unit 14 imparts, for example, a phase based on control by the control unit 13 to the optical signal.

[0025] The second-axis phase tilt imparting unit 15 imparts a phase tilt on the second axis, which is orthogonal to the first axis, to the input optical signal. The first axis and the second axis are, for example, the horizontal direction and the vertical direction. The second-axis phase tilt imparting unit 15 receives optical signals from a plurality of input terminals respectively corresponding to the plurality of output terminals of the first-axis phase tilt imparting unit 14. The second-axis phase tilt imparting unit 15 imparts different phase tilts to the optical signal according to the input terminal to which the optical signal is input. The second-axis phase tilt imparting unit 15 outputs the optical signal with the imparted phase tilt to the two-dimensional array antenna 16.

[0026] The two-dimensional array antenna 16 transmits the input optical signal. The two-dimensional array antenna 16, for example, multiplexes the input optical signal and the optical signal output from a light source different from the light source 11, and generates an electromagnetic wave having the frequency of the frequency difference between the two optical signals. For example, the two optical signals are photomixed by a photodiode to generate an electromagnetic wave. When the first axis is the horizontal direction and the second axis is the vertical direction, the two-dimensional array antenna 16 performs horizontal beam scanning based on the phase tilt on the first axis to determine the azimuth angle of the beam, and performs vertical beam scanning based on the phase tilt on the second axis to determine the elevation angle of the beam.

[0027] (First Embodiment) FIG. 2 is a diagram showing a configuration example of the transmission directivity control device 1 according to the first embodiment. The first-axis phase tilt imparting unit according to the first embodiment includes a first switching circuit 141 and a first-axis weighting circuit 142. The second-axis phase tilt imparting unit 15 includes a plurality of demultiplexers 151 and a second-axis weighting circuit 152. The two-dimensional array antenna 16 includes a plurality of antenna elements 161. Hereinafter, the case where the number of the demultiplexers 151 and the second-axis weighting circuit 152 is three each and the number of the antenna elements 161 is nine will be described, but the embodiment is not limited thereto.

[0028] The optical modulator 12 according to the first embodiment is controlled by the control unit 13 and outputs an optical signal of any one of the three wavelengths λ1, λ2, and λ3.

[0029] The first switching circuit 141 includes one input terminal and three output terminals. The first switching circuit 141 outputs the optical signal input to one input terminal from the optical modulator 12 from any one of the three output terminals. The output terminal from which the first switching circuit 141 outputs the optical signal is controlled by the control unit 13. The first switching circuit 141 is, for example, an optical switch.

[0030] The first-axis weighting circuit 142 includes three input terminals and three output terminals. The three input terminals of the first-axis weighting circuit 142 are respectively connected to the three output terminals of the first switching circuit 141. The first-axis weighting circuit 142 imparts different phase tilts depending on the input terminal to which the optical signal is input, which is the phase tilt in the first axis. The first-axis weighting circuit 142 outputs the optical signal with the phase imparted from the three output terminals. For example, when an optical signal is input to the first input terminal, the first-axis weighting circuit 142 outputs an optical signal without phase from the first output terminal, an optical signal with phase φ H1 from the second output terminal, and an optical signal with phase 2φ H1 from the third output terminal. For example, when an optical signal is input to the second input terminal, the first-axis weighting circuit 142 outputs an optical signal without phase from the first output terminal, an optical signal with phase φ H2 from the second output terminal, and an optical signal with phase 2φ H2Outputs the optical signal with the phase imparted from the third output terminal. For example, when an optical signal is input to the third input terminal, the first-axis weighting circuit 142 outputs an optical signal without imparting a phase from the first output terminal, and outputs an optical signal with the phase φ H3 from the second output terminal, and outputs an optical signal with the phase 2φ H3 from the third output terminal. That is, the optical signal input to the first input terminal is imparted with a phase gradient of 0, φ H1 , 2φ H1 , the optical signal input to the second input terminal is imparted with a phase gradient of 0, φ H2 , 2φ H2 , and the optical signal input to the third input terminal is imparted with a phase gradient of 0, φ H3 , 2φ H3 . More specifically, the phase gradient is 0 degrees, 45 degrees, 90 degrees, or 0 degrees, 90 degrees, 180 degrees, etc. The first-axis weighting circuit 142 does not necessarily need to output an optical signal without imparting a phase. For example, the phase gradient to be imparted may be φ, 2φ, 3φ.

[0031] The demultiplexer 151 demultiplexes the optical signal input from the first-axis phase-gradient imparting section 14. The demultiplexer 151 is designed to demultiplex optical signals with wavelengths λ1, λ2, and λ3. The demultiplexer 151 has three output terminals and outputs the demultiplexed optical signals from different output terminals depending on the wavelength. That is, the demultiplexer 151 outputs the optical signal with wavelength λ1 from the first output terminal, the optical signal with wavelength λ2 from the second output terminal, and the optical signal with wavelength λ3 from the third output terminal. The demultiplexer 151 is, for example, an AWG (Arrayed waveguide gratings).

[0032] The second-axis weighting circuit 152 has three input terminals and three output terminals. The three input terminals of the second-axis weighting circuit 152 are respectively connected to the three output terminals of the demultiplexer 151. The second-axis weighting circuit 152 imparts different phase inclinations according to the input terminals to which the optical signals are input, which are the phase inclinations on the second axis. The second-axis weighting circuit 152 outputs the optical signals with the imparted phases from the three output terminals. For example, when an optical signal is input to the first input terminal, the second-axis weighting circuit 152 outputs an optical signal without imparting a phase from the first output terminal, an optical signal with a phase φ V1 from the second output terminal, and an optical signal with a phase 2φ V1 from the third output terminal. For example, when an optical signal is input to the second input terminal, the second-axis weighting circuit 152 outputs an optical signal without imparting a phase from the first output terminal, an optical signal with a phase φ V2 from the second output terminal, and an optical signal with a phase 2φ V2 from the third output terminal. For example, when an optical signal is input to the third input terminal, the second-axis weighting circuit 152 outputs an optical signal without imparting a phase from the first output terminal, an optical signal with a phase φ V3 from the second output terminal, and an optical signal with a phase 2φ V3 from the third output terminal. That is, phase inclinations of 0, φ V1 , 2φ V1 are imparted to the optical signal input to the first input terminal, phase inclinations of 0, φ V2 , 2φ V2 are imparted to the optical signal input to the second input terminal, and phase inclinations of 0, φ V3 , 2φ V3 are imparted to the optical signal input to the third input terminal. More specifically, the phase inclinations are 0 degrees, 45 degrees, 90 degrees, or 0 degrees, 90 degrees, 180 degrees, etc. The second-axis weighting circuit 152 does not necessarily need to output an optical signal without imparting a phase. For example, the imparted phase inclinations may be φ, 2φ, 3φ.

[0033] The first-axis weighting circuit 142 and the second-axis weighting circuit 152 impart a phase gradient to the optical signal by means of a delay line, a high-dispersion line, a resonant ring, a matrix circuit, or the like. The matrix circuit is, for example, a Butler Matrix or a Blass Matrix.

[0034] As described above, nine optical signals with different combinations of phase gradients are output from the second-axis phase-gradient imparting section 15 due to the wavelength and the phase gradients of the optical signals input to the wavelength and demultiplexers 151-1 to 151-3.

[0035] The two-dimensional array antenna 16 includes nine antenna elements 161. The nine optical signals output from the second-axis phase-gradient imparting section 15 are respectively input to the nine antenna elements 161. The antenna element 161 converts the input optical signal into an RF signal and transmits it.

[0036] FIG. 3 is a flowchart showing the operation of the transmission directivity control device 1 according to the first embodiment. The optical modulator 12 generates an optical signal (step S10). The first switching circuit 141 outputs the input optical signal from any of a plurality of terminals (step S11). The first-axis weighting circuit 142 imparts a phase gradient to the optical signal input from the first switching circuit 141 (step S12). The demultiplexer 151 demultiplexes the optical signal input from the first-axis weighting circuit 142 (step S13). Thereafter, the second-axis weighting circuit 152 imparts a phase gradient to the demultiplexed optical signal (step S14). The antenna element 161 converts the optical signal into an RF signal (step S15).

[0037] As described above, the transmission directivity control device 1 can perform weighting by two axes using an optical circuit and electronically perform beam steering. Further, even if the number of antenna elements increases, it is only necessary to change the internal configuration of the first-axis phase-gradient imparting section 14 and the second-axis phase-gradient imparting section 15 and increase the number of connections between the antenna element 161 and the first-axis phase-gradient imparting section 14 and the second-axis phase-gradient imparting section 15, and complexity can be suppressed.

[0038] (Modification Example 1 of the First Embodiment) FIG. 4 is a diagram showing a modification example of the transmission directivity control device 1 according to the first embodiment. Different from the transmission directivity control device 1 shown in FIG. 3, the transmission directivity control device 1 shown in FIG. 2 includes two light sources 11 and two optical modulators 12, and the first switching circuit 141 includes two input terminals.

[0039] The first switching circuit 141 independently outputs the optical signals input to the two input terminals from any one of the three output terminals based on the control by the control unit 13. The first switching circuit 141 is, for example, a matrix switch.

[0040] When the wavelengths of the optical signals output from the two optical modulators 12 are not equal, the two optical signals may be output from the same output terminal of the first switching circuit 141.

[0041] Thereby, the transmission directivity control device 1 shown in FIG. 3 can transmit two beams from the two-dimensional array antenna 16. Similarly, by increasing the number of input terminals of the first switching circuit 141 to three or more, three or more multi-beams can be transmitted.

[0042] (Modification Example 2 of the First Embodiment) In the above description, the case where the array antenna is square, that is, the case where the number of the demultiplexers 151 is equal to the number of optical signals output by the demultiplexer 151 after demultiplexing, has been described, but the present invention is not limited thereto, and the number of the demultiplexers 151 and the number of optical signals output by the demultiplexer 151 after demultiplexing may not be equal. FIG. 5 is a diagram showing a modification example of the transmission directivity control device 1 according to the first embodiment. In the transmission directivity control device 1 shown in FIG. 5, the demultiplexer 151 demultiplexes into eight optical signals. At this time, the optical modulator 12 outputs optical signals of eight wavelengths, and the second axis weighting circuit 152 includes eight input terminals and eight output terminals. At this time, the two-dimensional array antenna 16 becomes an 8×3 two-dimensional array antenna. In the modification example of the transmission directivity control device 1 shown in FIG. 5, even when the number of antenna elements 161 of the two-dimensional array antenna 16 increases, an increase in the number of weighting circuits can be prevented.

[0043] (Modification Example 3 of the First Embodiment) FIG. 6 is a diagram showing a modification example of the transmission directivity control device 1 according to the first embodiment. In the transmission directivity control device 1 shown in FIG. 6, the first switching circuit 141 includes eight output terminals. At this time, the first-axis weighting circuit 142 includes eight input terminals and eight output terminals, and outputs optical signals with different phase inclinations from the eight output terminals, where the input terminals to which the optical signals are input are different. At this time, the second-axis phase inclination imparting unit 15 includes eight demultiplexers 151 and a second-axis weighting circuit 152. At this time, the two-dimensional array antenna 16 is a 3×8 two-dimensional array antenna. In the modification example of the transmission directivity control device 1 shown in FIG. 6, even when the number of antenna elements 161 of the two-dimensional array antenna 16 increases, the required optical frequency bandwidth can be suppressed to be small.

[0044] (Second Embodiment) FIG. 7 is a diagram showing a configuration example of the transmission directivity control device 1 according to the second embodiment. The first-axis phase inclination imparting unit 14 according to the second embodiment includes a demultiplexer 143, which is different from the first-axis phase inclination imparting unit 14 according to the first embodiment. In the second embodiment, the control unit 13 controls the light source 11 so that the optical modulator 12 outputs an optical signal of one wavelength from nine different wavelengths λ1, λ2, λ3, λ4, λ5, λ6, λ7, λ8, λ9.

[0045] The demultiplexer 143 includes one input terminal and three output terminals. The demultiplexer 143 demultiplexes the optical signal input to the input terminal from the optical modulator 12 and outputs the optical signal from any one of the three output terminals. The demultiplexer 143 outputs the optical signals of wavelengths λ1, λ2, λ3 from the first output terminal, the optical signals of wavelengths λ4, λ5, λ6 from the second output terminal, and the optical signals of wavelengths λ7, λ8, λ9 from the third output terminal. The demultiplexer 143 is, for example, an AWG.

[0046] In the optical demultiplexers 151-1 to 151-3 according to the second embodiment, different-wavelength optical signals demultiplexed by the optical demultiplexer 143 are respectively input, which is different from the optical demultiplexers 151-1 to 151-3 according to the first embodiment. The optical demultiplexers 151-1 to 151-3 according to the second embodiment demultiplex the input optical signals with different wavelengths. The optical demultiplexer 151-1 demultiplexes the optical signals with wavelengths λ1, λ2, and λ3, the optical demultiplexer 151-2 demultiplexes the optical signals with wavelengths λ4, λ5, and λ6, and the optical demultiplexer 151-3 demultiplexes the optical signals with wavelengths λ7, λ8, and λ9. The optical demultiplexer 151 according to the second embodiment is a filter having periodic transmission characteristics and is created using, for example, an optical ring resonator or an optical comb.

[0047] FIG. 8 is a flowchart showing the operation of the transmission directivity control device 1 according to the second embodiment. The optical modulator 12 generates an optical signal (step S20). The optical demultiplexer 143 demultiplexes the input optical signal and outputs it from any of a plurality of terminals (step S21). The first-axis weighting circuit 142 imparts a phase tilt to the optical signal input from the optical demultiplexer 143 (step S22). The optical demultiplexer 151 demultiplexes the optical signal input from the first-axis weighting circuit 142 (step S23). Thereafter, the second-axis weighting circuit 152 imparts a phase tilt to the demultiplexed optical signal (step S24). The antenna element 161 extracts an RF signal from the optical signal (step S25).

[0048] As described above, the transmission directivity control device 1 according to the second embodiment is different from the transmission directivity control device 1 according to the first embodiment in that the first-axis phase tilt imparting unit 14 includes the optical demultiplexer 143, increases the number of wavelengths of the optical signals that the optical modulator 12 can output, and makes the wavelengths of the optical signals demultiplexed by the plurality of optical demultiplexers 151 different. Thereby, the transmission directivity control device 1 according to the second embodiment can perform electronic beam steering only by controlling the wavelength of the light output from the light source 11.

[0049] (Modification Example of the Second Embodiment) FIG. 9 is a diagram showing a modified example of the transmission directivity control device 1 according to the second embodiment. The transmission directivity control device 1 shown in FIG. 9 is different from the transmission directivity control device 1 shown in FIG. 7 in that it includes two light sources 11 and two optical modulators 12, and an optical combiner 17. The optical combiner 17 combines the optical signals input from the two optical modulators 12 and outputs them to the first-axis phase tilt imparting unit 14. The optical combiner 17 is, for example, an AWG. The combined optical signal is demultiplexed by the demultiplexer 143 and the demultiplexer 151 based on its wavelength. Thereby, the transmission directivity control device 1 shown in FIG. 9 can transmit two beams from the two-dimensional array antenna 16. Similarly, by combining three or more optical signals by the optical combiner 17, three or more multi-beams can be transmitted.

[0050] Also, in the second embodiment, in the same manner as in the first embodiment, the number of demultiplexers 151 and the number of optical signals output after demultiplexing by the demultiplexers 151 do not have to be equal, and the two-dimensional antenna array does not have to be square.

[0051] As described above, an embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist of the present invention.

Description of Reference Numerals

[0052] 1 Transmission directivity control device, 11 Light source, 12 Optical modulator, 13 Control unit, 14 First-axis phase tilt imparting unit, 141 First switching circuit, 142 First-axis weighting circuit, 143 Demultiplexer, 15 Second-axis phase tilt imparting unit, 151 Demultiplexer, 152 Second-axis weighting circuit, 16 Two-dimensional array antenna, 161 Antenna element, 17 Optical combiner

Claims

1. a first-axis phase gradient imparting unit that imparts, to an input optical signal, a phase gradient on a first axis that is a certain axis in space, and outputs the optical signal with different phase gradients according to control content; a second-axis phase gradient imparting unit that imparts, to the optical signal input from the first-axis phase gradient imparting unit, a phase gradient on a second axis orthogonal to the first axis, and imparts different phase gradients according to the wavelength of the optical signal input from the first-axis phase gradient imparting unit; A transmission directivity control device comprising the above.

2. The first-axis phase gradient imparting unit includes a first switching circuit and a first-axis weighting circuit, The first switching circuit changes a terminal for outputting an optical signal input by control, The first-axis weighting circuit changes the phase gradient imparted to the optical signal for each terminal input from the first switching circuit, The transmission directivity control device according to Claim 1.

3. The first-axis phase gradient imparting unit imparts, to the input optical signal, different phase gradients according to the wavelength of the input optical signal, The transmission directivity control device according to Claim 1.

4. a first-axis phase gradient imparting step of imparting, to an input optical signal, a phase gradient on a first axis that is a certain axis in space, and outputting the optical signal with different phase gradients based on control content; a second-axis phase gradient imparting step of imparting, to the optical signal with the phase gradient on the first axis imparted thereto, a phase gradient on a second axis orthogonal to the first axis, and imparting different phase gradients according to the wavelength of the optical signal; A transmission directivity control method having the above.

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