Control device, control method, and program

Abstract

Provided is a control device capable of reducing costs required for manufacture, use, or the like of an optical circuit. The control device comprises a control unit capable of operating, as two or more unitary matrix calculation circuits, an optical switch circuit including N × N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer of 8 or more.

Description

Control device, control method, and program

[0001] This application claims priority to Japanese Patent Application No. 2023-123530, filed on July 28, 2023, the contents of which are incorporated herein by reference.

[0002] 2. Description of the Related Art In recent years, research and development has been conducted on optical circuits that perform processing using optical signals.

[0003] In this regard, optical switch circuits are known that efficiently switch optical signals required for optical communications, optical interconnects, etc. without photoelectric conversion, using the optical signals as they are (see Non-Patent Documents 1 and 2).

[0004] Furthermore, Clements-type optical circuits and Bell-type optical circuits are known as unitary matrix calculation circuits that efficiently perform unitary matrix calculations required for deep learning and the like using optical signals (see Non-Patent Documents 3 and 4).

[0005] Keijiro Suzuki, et al., "Ultra-compact 8 × 8 strictly-non-blocking Si-wire PILOSS switch," OPTICS EXPRESS, Vol. 22, Issue 4, 24 February 2014, pp. 3887-3894.Ken Tanizawa, et al., "Ultra-compact 32 × 32 strictly-non-blocking Si-wire optical switch with fan-out LGA interposer," OPTICS EXPRESS, Vol. 23, Issue 13, 29 June 2015, pp. 17599-17606.William R. Clements, et al., "Optimal design for universal multiport interferometers," Optica, Vol. 3, Issue 12, 6 December 2016, pp. 1460-1465.BA Bell, and IA Walmsley., "Further compactifying linear optical unitaries," APL Photonics, Vol. 6, Issue 7, 13 July 2021, 070804.

[0006] It is known that such optical switch circuits and unitary matrix operation circuits share common materials, manufacturing lines, manufacturing technologies, manufacturing management methods, etc. However, the optical switch circuits and unitary matrix operation circuits are manufactured and used as different optical circuits, which can make it difficult to reduce the costs required for manufacturing and using the optical circuits.

[0007] The present disclosure has been made in consideration of these circumstances, and aims to provide a control device, a control method, and a program that can reduce the costs required for manufacturing and using optical circuits.

[0008] According to a first aspect of the present disclosure, the control device includes a control unit capable of operating an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer greater than or equal to 8, as two or more unitary matrix operation circuits.

[0009] According to a second aspect of the present disclosure, a control method operates an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer greater than or equal to 8, as two or more unitary matrix operation circuits.

[0010] According to a third aspect of the present disclosure, a program causes a computer to operate an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer greater than or equal to 8, as two or more unitary matrix operation circuits.

[0011] According to the present disclosure, it is possible to reduce costs required for manufacturing and using optical circuits.

[0012] FIG. 1 is a diagram showing an example of the configuration of a control system 1. FIG. 1 is a diagram showing an example of the configuration of an optical switch circuit 10. FIG. 2 is a diagram showing a first example of the arrangement of a first Mach-Zehnder interferometer in an MZI matrix. FIG. 3 is a diagram showing a third example of the arrangement of a first Mach-Zehnder interferometer in an MZI matrix. FIG. 4 is a diagram showing a fourth example of the arrangement of a first Mach-Zehnder interferometer in an MZI matrix. FIG. 5 is a diagram showing a fourth example of the arrangement of a second Mach-Zehnder interferometer in an MZI matrix. FIG. 6 is a diagram showing a first modification example of specific example 1 of the arrangement of a first Mach-Zehnder interferometer operating as a first unitary matrix calculation circuit. 1 is a diagram showing an example of the arrangement of a first Mach-Zehnder interferometer when the number of optical signals output from the first unitary matrix calculation circuit is 6; FIG. 2 is a diagram showing an example of the arrangement of a second Mach-Zehnder interferometer when the number of optical signals output from the second unitary matrix calculation circuit is 6; FIG. 3 is a diagram showing an example of how three unitary matrix calculation circuits operate in an MZI matrix; FIG. 4 is a diagram showing an example of the arrangement of a first Mach-Zehnder interferometer when the number of optical signals input to the first unitary matrix calculation circuit is 8 and the number of optical signals output from the first unitary matrix calculation circuit is 8; FIG. 5 is a diagram showing an example of an MZI matrix in which a cross waveguide CS is connected to a first output port and a second output port of each Mach-Zehnder interferometer; FIG. 6 is a diagram showing an example of how a cross waveguide CS is connected to each of the first Mach-Zehnder interferometers shown in FIG. 3; FIG. 10 is a diagram showing an example of a flow of processing performed by the control device 20 to cause the optical switch circuit 10 to operate as a PILOSS optical switch circuit.

[0013] Embodiments Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0014] <Outline of Control System> First, an outline of the control system according to the embodiment will be described.

[0015] A control system according to an embodiment includes an optical switch circuit according to an embodiment and a control device according to an embodiment. The optical switch circuit includes N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer equal to or greater than 8. The control device includes a control unit capable of operating the optical switch circuit as two or more unitary matrix operation circuits.

[0016] As a result, the control system and the control device according to the embodiment can manufacture the optical switch circuit and the unitary matrix operation circuit as a single optical circuit, thereby reducing the costs required for manufacturing and using the optical circuit.

[0017] The following describes in detail the configuration of the control system according to the embodiment, the control device according to the embodiment, and the processing performed by the control device.

[0018] <Configuration of Control System> The configuration of the control system according to the embodiment will be described below using the control system 1 as an example.

[0019] FIG. 1 is a diagram illustrating an example of the configuration of a control system 1.

[0020] The control system 1 is a system that can selectively perform two operations: an operation of switching optical signals required for optical communications, optical interconnects, etc., and an operation of performing unitary matrix operations using optical signals.

[0021] The control system 1 includes, for example, an optical switch circuit 10 and a control device 20. Note that the control system 1 may include, in addition to the optical switch circuit 10 and the control device 20, other circuits, other components, other devices, etc.

[0022] The optical switch circuit 10 is a PILOSS (Path Independent Insertion Loss) optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer equal to or greater than 8. The following describes, as an example, a case where N is 8. In this embodiment, the Mach-Zehnder interferometers are known interferometers, and therefore detailed description thereof will be omitted.

[0023] FIG. 2 is a diagram illustrating an example of the configuration of an optical switch circuit 10. In this example, the optical switch circuit 10 includes 8×8 Mach-Zehnder interferometers arranged in an 8-row, 8-column matrix, as shown in FIG. 2 . Hereinafter, for convenience of explanation, one of two directions parallel to each row of the matrix formed by the 8×8 Mach-Zehnder interferometers included in the optical switch circuit 10 will be referred to as a first row direction, and the other of the two directions will be referred to as a second row direction. When it is not necessary to distinguish between the two directions, the two directions will be collectively referred to as a row direction. Hereinafter, for convenience of explanation, one of two directions parallel to each column of the matrix will be referred to as a first column direction, and the other of the two directions will be referred to as a second column direction. When it is not necessary to distinguish between the two directions, the two directions will be collectively referred to as a column direction. The arrows shown in FIG. 2 indicate the first row direction, second row direction, first column direction, and second column direction, respectively, in FIG. 2 . For ease of explanation, the matrix formed by the 8 × 8 Mach-Zehnder interferometers included in the optical switch circuit 10 will be referred to simply as an MZI (Mach-Zehnder Interferometer) matrix. For ease of explanation, the input port on the first column side of the two input ports of each of the 8 × 8 Mach-Zehnder interferometers will be referred to as a first input port, and the input port on the second column side of the two input ports will be referred to as a second input port. For ease of explanation, the output port on the first column side of the two output ports of each of the 8 × 8 Mach-Zehnder interferometers will be referred to as a first output port, and the output port on the second column side of the two input ports will be referred to as a second output port. Also, for convenience of explanation, hereinafter, each of the eight rows included in the MZI matrix will be referred to as the first row, second row, third row, fourth row, fifth row, sixth row, seventh row, and eighth row in order from the first column direction side toward the second column direction. Also, for convenience of explanation, hereinafter, each of the eight columns included in the MZI matrix will be referred to as the first column, second column, third column, fourth column, fifth column, sixth column, seventh column, and eighth column in order from the first row direction side toward the second row direction.

[0024] Hereinafter, for convenience of explanation, the eight Mach-Zehnder interferometers included in the i-th row will be referred to as Mach-Zehnder interferometer Mi1, Mach-Zehnder interferometer Mi2, Mach-Zehnder interferometer Mi3, Mach-Zehnder interferometer Mi4, Mach-Zehnder interferometer Mi5, Mach-Zehnder interferometer Mi6, Mach-Zehnder interferometer Mi7, and Mach-Zehnder interferometer Mi8 in order from the first row direction to the second row direction, as shown in FIG. That is, for example, the eight Mach-Zehnder interferometers included in the first row are, in order from the first row direction toward the second row direction, Mach-Zehnder interferometer M11, Mach-Zehnder interferometer M12, Mach-Zehnder interferometer M13, Mach-Zehnder interferometer M14, Mach-Zehnder interferometer M15, Mach-Zehnder interferometer M16, Mach-Zehnder interferometer M17, and Mach-Zehnder interferometer M18. Furthermore, for example, the eight Mach-Zehnder interferometers included in the fifth row are, in order from the first row direction toward the second row direction, Mach-Zehnder interferometer M51, Mach-Zehnder interferometer M52, Mach-Zehnder interferometer M53, Mach-Zehnder interferometer M54, Mach-Zehnder interferometer M55, Mach-Zehnder interferometer M56, Mach-Zehnder interferometer M57, and Mach-Zehnder interferometer M58.

[0025] Furthermore, when i is any of 1 to 8, an input source of an optical signal is connected to each of the first input port and the second input port of the Mach-Zehnder interferometer Mi1 via a waveguide. The input source of the optical signal may be the control device 20 or another device that serves as an input source of an optical signal. In the example shown in FIG. 1 , the input source of the optical signal is a device different from the control device 20. Furthermore, when i is any of 1 to 8, an output destination of the optical signal is connected to each of the first output port and the second output port of the Mach-Zehnder interferometer Mi8 via a waveguide. The output destination of the optical signal may be the control device 20 or another circuit, another device, etc. that serves as an output destination of the optical signal. In the example shown in FIG. 1 , the output destination of the optical signal is a device different from the control device 20.

[0026] Furthermore, when j is any value from 2 to 8, the first input port of the Mach-Zehnder interferometer M1j is connected to the first output port of the Mach-Zehnder interferometer M1j-1 via a waveguide. For example, the first input port of the Mach-Zehnder interferometer M12 is connected to the first output port of the Mach-Zehnder interferometer M11 via a waveguide.

[0027] Furthermore, when j is any one of 1 to 7, the first output port of the Mach-Zehnder interferometer M1j is connected to the first input port of the Mach-Zehnder interferometer M1j+1 via a waveguide. For example, the first output port of the Mach-Zehnder interferometer M17 is connected to the first input port of the Mach-Zehnder interferometer M18 via a waveguide.

[0028] Furthermore, when j is any value from 2 to 8, the second input port of the Mach-Zehnder interferometer M8j is connected to the second output port of the Mach-Zehnder interferometer M8j-1 via a waveguide. For example, the second input port of the Mach-Zehnder interferometer M82 is connected to the second output port of the Mach-Zehnder interferometer M81 via a waveguide.

[0029] Furthermore, when j is any one of 1 to 7, the second output port of the Mach-Zehnder interferometer M8j is connected to the second input port of the Mach-Zehnder interferometer M8j+1 via a waveguide. For example, the second output port of the Mach-Zehnder interferometer M87 is connected to the second input port of the Mach-Zehnder interferometer M88 via a waveguide.

[0030] Furthermore, when i is any value from 2 to 8 and j is any value from 2 to 8, the first input port of the Mach-Zehnder interferometer Mij is connected to the second output port of the Mach-Zehnder interferometer Mi-1j-1 via a waveguide. For example, the first input port of the Mach-Zehnder interferometer M22 is connected to the second output port of the Mach-Zehnder interferometer M11 via a waveguide.

[0031] Furthermore, when i is any one of 1 to 7 and j is any one of 2 to 8, the second input port of the Mach-Zehnder interferometer Mij is connected to the first output port of the Mach-Zehnder interferometer Mi+1j-1 via a waveguide. For example, the second input port of the Mach-Zehnder interferometer M72 is connected to the first output port of the Mach-Zehnder interferometer M81 via a waveguide.

[0032] Furthermore, when i is any of 2 to 8 and j is any of 1 to 7, the first output port of the Mach-Zehnder interferometer Mij is connected to the second input port of the Mach-Zehnder interferometer Mi-1j+1 via a waveguide. For example, the first output port of the Mach-Zehnder interferometer M27 is connected to the second input port of the Mach-Zehnder interferometer M18 via a waveguide.

[0033] Furthermore, when i is any value from 1 to 7 and j is any value from 1 to 7, the second output port of the Mach-Zehnder interferometer Mij is connected to the first input port of the Mach-Zehnder interferometer Mi+1j+1 via a waveguide. For example, the second output port of the Mach-Zehnder interferometer M77 is connected to the first input port of the Mach-Zehnder interferometer M88 via a waveguide.

[0034] That is, as described above, the optical switch circuit 10 is a PILOSS optical switch circuit. Since the PILOSS optical switch circuit is a known circuit, further detailed description of the connection between two adjacent Mach-Zehnder interferometers in the 8 × 8 Mach-Zehnder interferometers of the optical switch circuit 10 will be omitted. Also, in FIG. 2 , to avoid cluttering the diagram, the waveguides parallel to the row direction are depicted as having a different waveguide length from the waveguides intersecting the row direction. In practice, the waveguides connecting two adjacent Mach-Zehnder interferometers in the 8 × 8 Mach-Zehnder interferometers may all have the same waveguide length, except for differences due to manufacturing errors. Also, the waveguides connecting two adjacent Mach-Zehnder interferometers in the 8 × 8 Mach-Zehnder interferometers may have different waveguide lengths. The waveguides parallel to the row direction may actually have the same waveguide length as the waveguides intersecting the row direction, except for differences due to manufacturing errors. Alternatively, a crossing waveguide structure used when two waveguides intersecting the row direction intersect each other may be inserted into the waveguides parallel to the row direction, so that the waveguides parallel to the row direction and the waveguides intersecting the row direction have the same insertion loss, except for differences due to manufacturing errors. Alternatively, a crossing waveguide structure need not be inserted into the waveguides parallel to the row direction.

[0035] 2 , for example, when a first optical signal is input to each of the first input ports of four Mach-Zehnder interferometers M11, M31, M51, and M71 and the second input ports of four Mach-Zehnder interferometers M21, M41, M61, and M81, the optical switch circuit 10 outputs the first optical signal from the first output port or the second output port of each of the eight Mach-Zehnder interferometers included in the eighth column by switching in accordance with the control of the control device 20. In the example shown in FIG. 2 , in this case, the first optical signal is output from each of the first output ports of four Mach-Zehnder interferometers M28, M48, M68, and M88 and the second output ports of four Mach-Zehnder interferometers M18, M38, M58, and M78.

[0036] 2 , for example, when a second optical signal is input to each of the second input ports of four Mach-Zehnder interferometers M11, M31, M51, and M71 and the first input ports of four Mach-Zehnder interferometers M21, M41, M61, and M81, the optical switch circuit 10 outputs the second optical signal from the first output port or the second output port of each of the eight Mach-Zehnder interferometers included in the eighth column by switching in accordance with the control of the control device 20. In the example shown in FIG. 2 , in this case, the second optical signal is output from each of the second output ports of four Mach-Zehnder interferometers M28, M48, M68, and M88 and the first output ports of four Mach-Zehnder interferometers M18, M38, M58, and M78.

[0037] 2, the switching of the first optical signal and the switching of the second optical signal are depicted as occurring simultaneously. This is because operating the optical switch circuit 10 to switch the first optical signal results in operating the optical switch circuit 10 to switch the second optical signal. This is also because operating the optical switch circuit 10 to switch the second optical signal results in operating the optical switch circuit 10 to switch the first optical signal. However, the switching of the first optical signal and the switching of the second optical signal cannot be controlled independently.

[0038] The optical switch circuit 10 switches such optical signals by operating each Mach-Zehnder interferometer in response to a control signal from the control device 20 .

[0039] The control device 20 may be any device capable of controlling the optical switch circuit 10, such as, but not limited to, an information processing device dedicated to controlling the optical switch circuit 10, a workstation, a desktop PC (Personal Computer), or a notebook PC. The control device 20 may also be a processor such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array). The following describes, as an example, a case where the control device 20 is a desktop PC.

[0040] The control device 20 operates the optical switch circuit 10 as a PILOSS optical switch circuit in response to the received operation.

[0041] Furthermore, the control device 20 can operate the optical switch circuit 10 as two or more unitary matrix operation circuits in accordance with the received operation. This allows the control system 1 and the control device 20 to manufacture the optical switch circuit 10 and the two or more unitary matrix operation circuits as a single optical circuit. As a result, the control system 1 and the control device 20 can reduce the costs required for manufacturing and using the optical circuit. The control device 20 can operate the optical switch circuit 10 as two or more unitary matrix operation circuits by a new control method as described below. For simplicity of explanation, the following description will be given, as an example, of a case in which the control device 20 can operate the optical switch circuit 10 as two unitary matrix operation circuits, a first unitary matrix operation circuit and a second unitary matrix operation circuit. Here, the second unitary matrix operation circuit refers to a unitary matrix operation circuit that does not include a Mach-Zehnder interferometer included in the first unitary matrix operation circuit. In other words, the second unitary matrix calculation circuit is a unitary matrix calculation circuit different from the first unitary matrix calculation circuit. Furthermore, for convenience of explanation, hereinafter, among the 8 × 8 Mach-Zehnder interferometers, each of the multiple Mach-Zehnder interferometers that operate as the first unitary matrix calculation circuit will be referred to as a first Mach-Zehnder interferometer. Furthermore, for convenience of explanation, hereinafter, among the 8 × 8 Mach-Zehnder interferometers, each of the multiple Mach-Zehnder interferometers that operate as the second unitary matrix calculation circuit will be referred to as a second Mach-Zehnder interferometer.

[0042] Here, we will explain the arrangement of the first Mach-Zehnder interferometer and the arrangement of the second Mach-Zehnder interferometer in the MZI matrix when the control device 20 operates the optical switch circuit 10 as the first unitary matrix calculation circuit and the second unitary matrix calculation circuit, respectively.

[0043] <Specific Example 1 of Arrangement> For example, the control device 20 operates the multiple first Mach-Zehnder interferometers as a first unitary matrix calculation circuit so that the MZI matrix includes multiple rows R1 in which the first Mach-Zehnder interferometer and a third Mach-Zehnder interferometer, which is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer, alternately position, among the 8 × 8 Mach-Zehnder interferometers, the multiple rows R1 are arranged consecutively in the column direction of the MZI matrix, and the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer alternately position in any of the columns included in the multiple rows R1 arranged consecutively in the column direction. When the first unitary matrix calculation circuit is operated in this manner, the arrangement of the first Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes, for example, the arrangement shown in FIG. 3. FIG. 3 is a diagram showing a first example of the arrangement of the first Mach-Zehnder interferometers in the MZI matrix. In the example shown in FIG. 3 , the first Mach-Zehnder interferometer and the third Mach-Zehnder interferometer are alternately positioned in all of the first to eighth rows. That is, in the example shown in FIG. 3 , all of the first to eighth rows in the MZI matrix correspond to row R1. However, in FIG. 3 , in order to clearly show the arrangement of the first Mach-Zehnder interferometer, the Mach-Zehnder interferometer corresponding to the third Mach-Zehnder interferometer is omitted from the MZI matrix. Also, in this example, the first Mach-Zehnder interferometer and the third Mach-Zehnder interferometer are alternately positioned in all of the first to eighth columns. Here, some or all of the multiple third Mach-Zehnder interferometers may be second Mach-Zehnder interferometers, or may be Mach-Zehnder interferometers other than the second Mach-Zehnder interferometer among the 8 × 8 Mach-Zehnder interferometers. In this example, all of the plurality of third Mach-Zehnder interferometers are second Mach-Zehnder interferometers, as shown in Fig. 4. When the first Mach-Zehnder interferometer is operated as the first unitary matrix operation circuit in this manner, the first unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as input and outputs seven optical signals, as shown in Fig. 3.However, in the example shown in FIG. 3 , each of the hatched Mach-Zehnder interferometers M12, M14, M16, M18, M38, M58, M78, M81, M83, M85, and M87 is a first Mach-Zehnder interferometer operated as a phase modulator. Here, operating as a phase modulator means that the Mach-Zehnder interferometer is in a Bar state. An optical signal input to a first input port is phase-modulated and then output from a first output port. An optical signal input to a second input port is phase-modulated and then output from a second output port. That is, the optical intensity branching ratio of each of the hatched Mach-Zehnder interferometers M12, M14, M16, M18, M38, M58, M78, M81, M83, M85, and M87 in FIG. 3 is 100:0 (Bar:Cross). On the other hand, the optical intensity branching ratios of the Mach-Zehnder interferometers M21, M23, M25, M27, M32, M34, M36, M41, M43, M45, M47, M52, M54, M56, M61, M63, M65, M67, M72, M74, and M76 not hatched in Fig. 3 are set to desired ratios according to desired unitary matrix operations. Furthermore, among the Mach-Zehnder interferometers hatched in Fig. 3, the Mach-Zehnder interferometers M18, M38, M58, and M78 may be in a cross state. An optical signal input to the first input port is modulated in phase and then output from the second output port. An optical signal input to the second input port is modulated in phase and then output from the first output port. That is, in this case, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M18, M38, M58, and M78 is 0:100 in terms of Bar:Cross.

[0044] On the other hand, for example, the control device 20 operates the plurality of second Mach-Zehnder interferometers as a second unitary matrix calculation circuit so that the MZI matrix includes a plurality of rows R2 in which the fourth Mach-Zehnder interferometer, which is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer, and the second Mach-Zehnder interferometer are alternately positioned, among the 8 × 8 Mach-Zehnder interferometers, the plurality of rows R2 are arranged consecutively in the column direction of the MZI matrix, and the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any of the columns included in the plurality of rows R2 arranged consecutively in the column direction. When the second unitary matrix calculation circuit is operated in this manner, the arrangement of the second Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes, for example, an arrangement as shown in FIG. 4. FIG. 4 is a diagram showing a first example of the arrangement of the second Mach-Zehnder interferometers in the MZI matrix. In the example shown in FIG. 4 , the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer are alternately positioned in all of the first to eighth rows. That is, in the example shown in FIG. 4 , all of the first to eighth rows in the MZI matrix correspond to row R2. However, in FIG. 4 , in order to clearly show the arrangement of the second Mach-Zehnder interferometer, the Mach-Zehnder interferometer corresponding to the fourth Mach-Zehnder interferometer is omitted from the MZI matrix. Also, in this example, the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer are alternately positioned in all of the first to eighth columns. Here, some or all of the multiple fourth Mach-Zehnder interferometers may be the first Mach-Zehnder interferometer, or may be a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the 8 × 8 Mach-Zehnder interferometers. In this example, all of the plurality of fourth Mach-Zehnder interferometers are first Mach-Zehnder interferometers as shown in Fig. 3. When the second Mach-Zehnder interferometer is operated as the second unitary matrix operation circuit in this manner, the second unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as input and outputs seven optical signals as shown in Fig. 4.However, in the example shown in Fig. 4, each of the hatched Mach-Zehnder interferometers M11, M13, M15, M17, M28, M48, M68, M82, M84, M86, and M88 is a second Mach-Zehnder interferometer operated as a phase modulator (Bar state). That is, the optical intensity branching ratio in each of the hatched Mach-Zehnder interferometers M11, M13, M15, M17, M28, M48, M68, M82, M84, M86, and M88 in Fig. 4 is 100:0 in terms of Bar:Cross. On the other hand, the optical intensity branching ratios of the Mach-Zehnder interferometers M22, M24, M26, M31, M33, M35, M37, M42, M44, M46, M51, M53, M55, M57, M62, M64, M66, M71, M73, M75, and M77 that are not hatched in Fig. 4 are set to desired ratios according to desired unitary matrix operations. Furthermore, among the Mach-Zehnder interferometers hatched in Fig. 4, the Mach-Zehnder interferometers M28, M48, M68, and M88 may be in a cross state. In other words, in this case, the optical intensity branching ratios of the Mach-Zehnder interferometers M28, M48, M68, and M88 are each 0:100 in terms of bar:cross.

[0045] 3 and 4, when the third Mach-Zehnder interferometer is the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer is the first Mach-Zehnder interferometer, the control device 20 operates the optical switch circuit 10 by dividing it into two unitary matrix operation circuits. In this case, the arrangement of the Mach-Zehnder interferometers formed by overlapping the first Mach-Zehnder interferometer shown in FIG. 3 and the second Mach-Zehnder interferometer shown in FIG. 4 coincides with the arrangement of the Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2.

[0046] Note that the waveguides through which optical signals propagate in the first unitary matrix calculation circuit and the waveguides through which optical signals propagate in the second unitary matrix calculation circuit may intersect but do not overlap. Therefore, the control device 20 can operate the optical switch circuit 10 in parallel as the first unitary matrix calculation circuit and the second unitary matrix calculation circuit. That is, the control system 1 can cause the optical switch circuit 10 to perform two unitary matrix calculations in parallel. This is also true when the first Mach-Zehnder interferometer is operated as the first unitary matrix calculation circuit and the second Mach-Zehnder interferometer is operated as the second unitary matrix calculation circuit so as to have a different arrangement.

[0047] Furthermore, the control device 20 can easily switch between operating the optical switch circuit 10 as a PILOSS optical switch circuit and operating the optical switch circuit 10 as a first unitary matrix calculation circuit and a second unitary matrix calculation circuit using a control signal. This means that the operation of the optical switch circuit 10 can be switched depending on the time of day. For example, in optical communications, optical interconnects, etc., the usage of the optical switch circuit 10 varies depending on the time of day. However, the system is designed with sufficient margin to handle peak usage without any problems. In such optical communications, optical interconnects, etc., the control device 20 can operate the optical switch circuit 10 as a PILOSS optical switch circuit for optical communications, optical interconnects, etc. during times of heavy usage, and as a unitary matrix calculation circuit for deep learning, etc. during times of light usage. This allows the control device 20 to reduce the standby time of the optical switch circuit 10 and allow users to use the optical switch circuit 10 efficiently. This is also true even when the first Mach-Zehnder interferometer is operated as a first unitary matrix calculation circuit so as to have another arrangement, and the second Mach-Zehnder interferometer is operated as a second unitary matrix calculation circuit so as to have another arrangement.

[0048] Furthermore, in the example shown in FIG. 3 , the control device 20 may be configured such that the number of optical signals input to the first unitary matrix calculation circuit and the number of optical signals output from the first unitary matrix calculation circuit are each six or less. In this case, for example, the number of rows functioning as row R1 shown in FIG. 3 among the eight rows (rows 1 to 8) is reduced, and as a result, the number of Mach-Zehnder interferometers operating as first Mach-Zehnder interferometers is also reduced. In the example shown in FIG. 3 , when the number of optical signals input to the first unitary matrix calculation circuit and the number of optical signals output from the first unitary matrix calculation circuit are each six or less, the arrangement of the first Mach-Zehnder interferometers can be easily specified in accordance with the rules for functioning as a unitary matrix calculation circuit. For this reason, a description of the arrangement with illustrations will be omitted here. Furthermore, the Mach-Zehnder interferometer operating as a phase modulator in the arrangement can also be easily specified in accordance with the rules. For this reason, a description of the Mach-Zehnder interferometer operating as a phase modulator in the arrangement with illustrations will also be omitted here. This is also true even when the first Mach-Zehnder interferometer is operated as a first unitary matrix calculation circuit so as to have another arrangement, and the second Mach-Zehnder interferometer is operated as a second unitary matrix calculation circuit so as to have another arrangement.

[0049] The control device 20 may also be configured to operate a part of the optical switch circuit 10 as a first unitary matrix operation circuit, operate another part of the optical switch circuit 10 as a second unitary matrix operation circuit, and operate a part or all of the remaining optical switch circuit 10 as PILOSS optical switch circuits. The control device 20 may also be configured to operate a part of the optical switch circuit 10 as a first unitary matrix operation circuit, operate another part of the optical switch circuit 10 as a second unitary matrix operation circuit, and not operate the remaining optical switch circuit 10. The control device 20 may also be configured to operate a part of the optical switch circuit 10 as a first unitary matrix operation circuit, operate another part of the optical switch circuit 10 as a PILOSS optical switch circuit, and not operate the remaining optical switch circuit 10. This is also true even when the first Mach-Zehnder interferometer is operated as a first unitary matrix calculation circuit so as to have another arrangement, and the second Mach-Zehnder interferometer is operated as a second unitary matrix calculation circuit so as to have another arrangement.

[0050] <Specific Example of Arrangement 2> For example, the control device 20 operates the multiple first Mach-Zehnder interferometers as a first unitary matrix calculation circuit so that the MZI matrix includes multiple rows R1 in which the third Mach-Zehnder interferometers and the first Mach-Zehnder interferometers are alternately positioned, and one row R3 in which eight first Mach-Zehnder interferometers are arranged, the multiple rows R1 are arranged continuously in the column direction of the MZI matrix, the third Mach-Zehnder interferometers and the first Mach-Zehnder interferometers are alternately positioned in any of the columns included in the multiple rows R1 arranged continuously in the column direction, and one row R3 is adjacent to one of two rows R1 located at both ends in the column direction among the multiple rows R1. When the first unitary matrix calculation circuit is operated in this way, the arrangement of the first Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes, for example, the arrangement shown in FIG. FIG. 5 is a diagram showing a second example of the arrangement of first Mach-Zehnder interferometers in an MZI matrix. In the example shown in FIG. 5, the first Mach-Zehnder interferometer and the third Mach-Zehnder interferometer are alternately positioned in all of the second to seventh rows. That is, each of the second to seventh rows corresponds to row R1. In this example, the second to seventh rows corresponding to row R1 are continuously aligned in the column direction of the MZI matrix. In this example, the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are alternately positioned in any of the columns included in the second to seventh rows that are continuously aligned in the column direction of the MZI matrix. In this example, eight first Mach-Zehnder interferometers are aligned in the eighth row. That is, the eighth row corresponds to row R3. In this example, the seventh row of the second to seventh rows corresponding to row R1 and the eighth row corresponding to row R3 are adjacent to each other in the column direction. 5, in order to clearly show the arrangement of the first Mach-Zehnder interferometer, the Mach-Zehnder interferometer corresponding to the third Mach-Zehnder interferometer is omitted from the MZI matrix. Also, in this example, the first Mach-Zehnder interferometer and the third Mach-Zehnder interferometer are alternately positioned in any of the columns included in the second to seventh rows corresponding to the plurality of rows R1 arranged consecutively in the column direction.When the first Mach-Zehnder interferometer is operated as a first unitary matrix operation circuit in this manner, the first unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as inputs and outputs seven optical signals, as shown in Fig. 5. However, in the example shown in Fig. 5, each of the Mach-Zehnder interferometers M21, M23, M25, M27, M38, M58, M78, M82, M84, M86, and M88 hatched in Fig. 5 is a first Mach-Zehnder interferometer operated as a phase modulator (Bar state). That is, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M21, M23, M25, M27, M38, M58, M78, M82, M84, M86, and M88 hatched in Fig. 5 is 100:0, in terms of Bar:Cross. On the other hand, the optical intensity branching ratios of the Mach-Zehnder interferometers M32, M34, M36, M41, M43, M45, M47, M52, M54, M56, M61, M63, M65, M67, M72, M74, M76, M81, M83, M85, and M87 that are not hatched in Fig. 5 are set to desired ratios according to desired unitary matrix operations. Furthermore, among the Mach-Zehnder interferometers hatched in Fig. 5, the Mach-Zehnder interferometers M38, M58, M78, and M88 may be in a cross state. In other words, in this case, the optical intensity branching ratios of the Mach-Zehnder interferometers M38, M58, M78, and M88 are each 0:100 in terms of bar:cross.

[0051] On the other hand, for example, the control device 20 operates the plurality of second Mach-Zehnder interferometers as a second unitary matrix calculation circuit so that the MZI matrix includes a plurality of rows R2 in which the fourth Mach-Zehnder interferometers and the second Mach-Zehnder interferometers are alternately positioned, and one row R4 in which eight second Mach-Zehnder interferometers are arranged, the plurality of rows R2 are arranged continuously in the column direction of the MZI matrix, the fourth Mach-Zehnder interferometers and the second Mach-Zehnder interferometers are alternately positioned in any of the columns included in the plurality of rows R2 arranged continuously in the column direction, and one row R4 is adjacent to one of the two rows R2 located at both ends in the column direction among the plurality of rows R2. When the second unitary matrix calculation circuit is operated in this manner, the arrangement of the second Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes, for example, an arrangement as shown in FIG. FIG. 6 is a diagram showing a second example of the arrangement of second Mach-Zehnder interferometers in an MZI matrix. In the example shown in FIG. 6, the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer are alternately positioned in all of the second to seventh rows. That is, each of the second to seventh rows corresponds to row R2. In this example, the second to seventh rows corresponding to row R2 are continuously aligned in the column direction of the MZI matrix. In this example, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any of the columns included in the second to seventh rows that are continuously aligned in the column direction of the MZI matrix. In this example, eight second Mach-Zehnder interferometers are aligned in the first row. That is, the first row corresponds to row R4. In this example, the second row of the second to seventh rows corresponding to row R2 and the first row corresponding to row R4 are adjacent in the column direction. 6, in order to clearly show the arrangement of the second Mach-Zehnder interferometer, the Mach-Zehnder interferometer corresponding to the fourth Mach-Zehnder interferometer is omitted from the MZI matrix. Also, in this example, the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer are alternately positioned in any of the columns included in the second to seventh rows corresponding to the plurality of rows R2 arranged consecutively in the column direction.When the second Mach-Zehnder interferometer is operated as a second unitary matrix operation circuit in this manner, the second unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as inputs and outputs seven optical signals, as shown in Fig. 6. However, in the example shown in Fig. 6, each of the Mach-Zehnder interferometers M12, M14, M16, M18, M28, M48, M68, M71, M73, M75, and M77 hatched in Fig. 6 is a second Mach-Zehnder interferometer operated as a phase modulator (Bar state). That is, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M12, M14, M16, M18, M28, M48, M68, M71, M73, M75, and M77 hatched in Fig. 6 is 100:0, in terms of Bar:Cross. On the other hand, the optical intensity branching ratios of the Mach-Zehnder interferometers M11, M13, M15, M17, M22, M24, M26, M31, M33, M35, M37, M42, M44, M46, M51, M53, M55, M57, M62, M64, and M66 that are not hatched in Fig. 6 are set to desired ratios according to desired unitary matrix operations. Furthermore, among the Mach-Zehnder interferometers hatched in Fig. 6, the Mach-Zehnder interferometers M18, M28, M48, and M68 may be in a cross state. In other words, in this case, the optical intensity branching ratios of the Mach-Zehnder interferometers M18, M28, M48, and M68 are each 0:100 in terms of bar:cross.

[0052] Here, when the third Mach-Zehnder interferometer is the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer is the first Mach-Zehnder interferometer as shown in Figures 5 and 6, the control device 20 divides the optical switch circuit 10 into two unitary matrix operation circuits and operates them. In this case, the arrangement of the Mach-Zehnder interferometers formed by overlapping the first Mach-Zehnder interferometer shown in Figure 5 and the second Mach-Zehnder interferometer shown in Figure 6 coincides with the arrangement of the Mach-Zehnder interferometers in the MZI matrix shown in Figure 2.

[0053] 5 and 6, the eight Mach-Zehnder interferometers in the first row may be operated as first Mach-Zehnder interferometers, and the eight Mach-Zehnder interferometers in the eighth row may be operated as second Mach-Zehnder interferometers. In this case, the four first Mach-Zehnder interferometers in the seventh row are operated as phase modulators (Bar state). In this case, each of the Mach-Zehnder interferometers M11, M13, M15, M17, and M18 in the first row is also operated as a phase modulator (Bar state). In this case, each of the Mach-Zehnder interferometers M38 and M58 is also operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M11, M13, M15, M17, M18, M38, M58, M72, M74, M76, and M78 is 100:0 (Bar:Cross). Meanwhile, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M12, M14, and M16 included in the first row is a desired ratio according to a desired unitary matrix operation. The Mach-Zehnder interferometers M18, M38, M58, and M78 may be in the Cross state. In this case, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M18, M38, M58, and M78 is 0:100 (Bar:Cross). Furthermore, in this case, the four second Mach-Zehnder interferometers included in the second row are operated as phase modulators (Bar state). In this case, each of the Mach-Zehnder interferometers M81, M83, M85, M87, and M88 included in the eighth row is also operated as a phase modulator (Bar state). In this case, each of the Mach-Zehnder interferometers M48 and M68 is also operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M22, M24, M26, M28, M48, M68, M81, M83, M85, M87, and M88 is 100:0 (Bar:Cross). On the other hand, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M82, M84, and M86 included in the eighth row is a desired ratio according to a desired unitary matrix operation.Furthermore, the Mach-Zehnder interferometers M28, M48, M68, and M88 may be in a Cross state. That is, in this case, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M28, M48, M68, and M88 is Bar:Cross, or 0:100. Even when the first Mach-Zehnder interferometer is operated as the first unitary matrix operation circuit and the second Mach-Zehnder interferometer is operated as the second unitary matrix operation circuit in this way, each of the first unitary matrix operation circuit and the second unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as input and performs unitary matrix operation with seven optical signals as output.

[0054] <Specific Example of Arrangement 3> For example, the control device 20 operates the multiple first Mach-Zehnder interferometers as a first unitary matrix calculation circuit so that the MZI matrix includes multiple rows R1 in which the third Mach-Zehnder interferometers and the first Mach-Zehnder interferometers are alternately positioned and multiple rows R3 in which eight first Mach-Zehnder interferometers are arranged, the multiple rows R1 are arranged consecutively in the column direction of the MZI matrix, the multiple rows R3 are arranged consecutively in the column direction, the third Mach-Zehnder interferometers and the first Mach-Zehnder interferometers are arranged alternately in any column included in the multiple rows R1 arranged consecutively in the column direction, and any of the two rows R1 located at both ends in the column direction among the multiple rows R1 is adjacent to the multiple rows R3. When the first unitary matrix calculation circuit is operated in this way, the arrangement of the first Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 is, for example, an arrangement as shown in FIG. FIG. 7 is a diagram showing a third example of the arrangement of first Mach-Zehnder interferometers in an MZI matrix. In the example shown in FIG. 7, the first Mach-Zehnder interferometer and the third Mach-Zehnder interferometer are alternately positioned in each of the fourth and fifth rows. That is, each of the fourth and fifth rows corresponds to row R1. In this example, the fourth and fifth rows corresponding to row R1 are continuously arranged in the column direction of the MZI matrix. In this example, the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are alternately positioned in any of the columns included in the fourth and fifth rows that are continuously arranged in the column direction of the MZI matrix. In this example, eight first Mach-Zehnder interferometers are arranged in each of the sixth to eighth rows. That is, each of the sixth to eighth rows corresponds to row R3. In this example, the sixth to eighth rows, which correspond to a plurality of rows R3, are continuously arranged in the column direction. In this example, the fifth row of the fourth and fifth rows corresponding to row R1 and the sixth to eighth rows corresponding to row R3 are adjacent to each other in the column direction. However, in order to clearly show the arrangement of the first Mach-Zehnder interferometer, the Mach-Zehnder interferometer corresponding to the third Mach-Zehnder interferometer among the MZI matrix is ​​omitted from Fig. 7 .In this example, the first Mach-Zehnder interferometer and the third Mach-Zehnder interferometer are alternately positioned in any of the columns included in the fourth and fifth rows, which correspond to a plurality of rows R1 arranged consecutively in the column direction. When the first Mach-Zehnder interferometer is operated as a first unitary matrix operation circuit in this manner, the first unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as inputs and outputs seven optical signals, as shown in Fig. 7. However, in the example shown in Fig. 7, each of the hatched Mach-Zehnder interferometers M41, M43, M45, M47, M58, M62, M64, M66, M78, and M88 is a first Mach-Zehnder interferometer that is operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the hatched Mach-Zehnder interferometers M41, M43, M45, M47, M58, M62, M64, M66, M78, and M88 in Fig. 7 is 100:0 (Bar:Cross). On the other hand, the optical intensity branching ratio of each of the non-hatched Mach-Zehnder interferometers M52, M54, M56, M61, M63, M65, M67, M71 to M77, and M81 to M87 in Fig. 7 is a desired ratio in accordance with a desired unitary matrix operation. Furthermore, of the hatched Mach-Zehnder interferometers in Fig. 7, the Mach-Zehnder interferometers M58, M68, M78, and M88 may be in a Cross state. That is, in this case, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M58, M68, M78, and M88 is 0:100 in terms of Bar:Cross.

[0055] On the other hand, for example, the control device 20 operates the plurality of second Mach-Zehnder interferometers as a second unitary matrix calculation circuit so that the MZI matrix includes a plurality of rows R2 in which the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned, and a plurality of rows R4 in which eight second Mach-Zehnder interferometers are arranged, the plurality of rows R2 are arranged consecutively in the column direction of the MZI matrix, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any of the columns included in the plurality of rows R2 arranged consecutively in the column direction, and one of the two rows R2 located at both ends in the column direction among the plurality of rows R2 is adjacent to the plurality of rows R4. When the second unitary matrix calculation circuit is operated in this manner, the arrangement of the second Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes the arrangement shown in FIG. 8. FIG. 8 is a diagram showing a third example of the arrangement of the second Mach-Zehnder interferometers in the MZI matrix. In the example shown in FIG. 8 , the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer are alternately positioned in each of the fourth and fifth rows. That is, each of the fourth and fifth rows corresponds to row R2. In addition, in this example, the fourth and fifth rows corresponding to row R2 are continuously arranged in the column direction of the MZI matrix. In addition, in this example, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any of the columns included in the fourth and fifth rows that are continuously arranged in the column direction of the MZI matrix. In addition, in this example, eight second Mach-Zehnder interferometers are aligned in each of the first to third rows. That is, each of the first to third rows corresponds to row R4. In addition, in this example, the first to third rows, which correspond to a plurality of rows R4, are continuously aligned in the column direction. In this example, the fourth row of the fourth and fifth rows corresponding to row R2 and the first to third rows corresponding to row R4 are adjacent to each other in the column direction. However, in order to clearly show the arrangement of the second Mach-Zehnder interferometer, the Mach-Zehnder interferometer corresponding to the fourth Mach-Zehnder interferometer is omitted from Fig. 8 , among the Mach-Zehnder interferometers included in the MZI matrix.In addition, in this example, the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer are alternately positioned in any of the columns included in the fourth and fifth rows, which correspond to a plurality of rows R2 arranged consecutively in the column direction. When the second Mach-Zehnder interferometer is operated as the second unitary matrix operation circuit in this manner, the second unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as inputs and outputs seven optical signals, as shown in Fig. 8. However, in the example shown in Fig. 8, each of the hatched Mach-Zehnder interferometers M18, M28, M32, M34, M36, M38, M48, M51, M53, M55, and M57 in Fig. 8 is a second Mach-Zehnder interferometer that is operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the hatched Mach-Zehnder interferometers M18, M28, M32, M34, M36, M38, M48, M51, M53, M55, and M57 in Fig. 8 is 100:0 (Bar:Cross). On the other hand, the optical intensity branching ratio of each of the non-hatched Mach-Zehnder interferometers M11 to M17, M21 to M27, M31, M33, M35, M37, M42, M44, and M46 in Fig. 8 is a desired ratio according to a desired unitary matrix operation. Furthermore, of the hatched Mach-Zehnder interferometers in Fig. 8, the Mach-Zehnder interferometers M18, M28, M38, and M48 may be in a Cross state. That is, in this case, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M18, M28, M38, and M48 is 0:100 in terms of Bar:Cross.

[0056] Here, when the third Mach-Zehnder interferometer is the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer is the first Mach-Zehnder interferometer as shown in Figures 7 and 8, the control device 20 divides the optical switch circuit 10 into two unitary matrix operation circuits and operates them. In this case, the arrangement of the Mach-Zehnder interferometers formed by overlapping the first Mach-Zehnder interferometer shown in Figure 7 and the second Mach-Zehnder interferometer shown in Figure 8 coincides with the arrangement of the Mach-Zehnder interferometers in the MZI matrix shown in Figure 2.

[0057] 7 and 8, the 24 Mach-Zehnder interferometers included in the first to third rows may be operated as first Mach-Zehnder interferometers, and the 24 Mach-Zehnder interferometers included in each of the sixth to eighth rows may be operated as second Mach-Zehnder interferometers. In this case, each of the four first Mach-Zehnder interferometers M52, M54, M56, and M58 included in the fifth row may be operated as a phase modulator (Bar state). In this case, each of the Mach-Zehnder interferometers M31, M33, M35, M37, and M38 included in the third row may also be operated as a phase modulator (Bar state). In this case, each of the Mach-Zehnder interferometers M18 and M28 may also be operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M18, M28, M31, M33, M35, M37, M38, M52, M54, M56, and M58 is 100:0 in terms of bar:cross. Meanwhile, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M11 to M17, M21 to M27, M32, M34, M36, M41, M43, M45, and M47 is a desired ratio according to a desired unitary matrix operation. Furthermore, the Mach-Zehnder interferometers M18, M28, M38, and M58 may be in a cross state. That is, in this case, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M18, M28, M38, and M58 is 0:100 in terms of bar:cross. In this case, each of the four second Mach-Zehnder interferometers M42, M44, M46, and M48 included in the fourth row is operated as a phase modulator (Bar state). In this case, each of the Mach-Zehnder interferometers M61, M63, M65, M67, and M68 included in the sixth row is also operated as a phase modulator (Bar state). In this case, each of the Mach-Zehnder interferometers M78 and M88 is also operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M42, M44, M46, M48, M61, M63, M65, M67, M68, M78, and M88 is 100:0 (Bar:Cross).On the other hand, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M51, M53, M55, M57, M62, M64, M66, M71 to M77, and M81 to M87 is a desired ratio according to a desired unitary matrix operation. Furthermore, the Mach-Zehnder interferometers M48, M68, M78, and M88 may be in a cross state. In other words, in this case, the optical intensity branching ratio of each of the Mach-Zehnder interferometers M48, M68, M78, and M88 is 0:100 (Bar:Cross). In this way, even when the first Mach-Zehnder interferometer is operated as a first unitary matrix calculation circuit and the second Mach-Zehnder interferometer is operated as a second unitary matrix calculation circuit, each of the first unitary matrix calculation circuit and the second unitary matrix calculation circuit operates as a unitary matrix calculation circuit that performs unitary matrix calculations with seven optical signals as input and seven optical signals as output.

[0058] <Specific Example of Arrangement 4> For example, the control device 20 operates a plurality of first Mach-Zehnder interferometers as a first unitary matrix calculation circuit so that the MZI matrix includes a plurality of rows R3, each of which includes eight first Mach-Zehnder interferometers, and the plurality of rows R3 are arranged consecutively in the column direction of the MZI matrix. When the first unitary matrix calculation circuit is operated in this manner, the arrangement of the first Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes, for example, an arrangement such as that shown in FIG. 9. FIG. 9 is a diagram showing a fourth example of the arrangement of first Mach-Zehnder interferometers in an MZI matrix. In the example shown in FIG. 9, eight first Mach-Zehnder interferometers are arranged in each of the fifth to eighth rows. That is, each of the fifth to eighth rows corresponds to row R3. In this example, the fifth to eighth rows, which correspond to row R3, are arranged consecutively in the column direction of the MZI matrix. However, in Fig. 9, in order to clearly show the arrangement of the first Mach-Zehnder interferometer, Mach-Zehnder interferometers other than the first Mach-Zehnder interferometer among the MZI matrix are omitted. When the first Mach-Zehnder interferometer is operated as a first unitary matrix operation circuit in this way, the first unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as input and outputs seven optical signals, as shown in Fig. 9. However, in the example shown in Fig. 9, each of the hatched Mach-Zehnder interferometers M51 to M58, M68, M78, and M88 in Fig. 9 is a first Mach-Zehnder interferometer that is operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the hatched Mach-Zehnder interferometers M51 to M58, M68, M78, and M88 in Fig. 9 is 100:0 (Bar:Cross). On the other hand, the optical intensity branching ratio of each of the non-hatched Mach-Zehnder interferometers M61 to M67, M71 to M77, and M81 to M87 in Fig. 9 is a desired ratio according to a desired unitary matrix operation. Furthermore, of the hatched Mach-Zehnder interferometers in Fig. 9, the Mach-Zehnder interferometers M58, M68, M78, and M88 may be in a Cross state.That is, in this case, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M58, M68, M78, and M88 is 0:100 in terms of Bar:Cross.

[0059] On the other hand, for example, the control device 20 operates the plurality of second Mach-Zehnder interferometers as a second unitary matrix calculation circuit so that the MZI matrix includes a plurality of rows R4, each of which includes eight second Mach-Zehnder interferometers, and the plurality of rows R4 are arranged consecutively in the column direction of the MZI matrix. When the first unitary matrix calculation circuit is operated in this manner, the arrangement of the second Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2 becomes, for example, an arrangement such as that shown in FIG. 10. FIG. 10 is a diagram showing a fourth example of the arrangement of the second Mach-Zehnder interferometers in the MZI matrix. In the example shown in FIG. 10, eight second Mach-Zehnder interferometers are arranged in each of the first to fourth rows. That is, each of the first to fourth rows corresponds to row R4. In this example, the first to fourth rows, which correspond to row R4, are arranged consecutively in the column direction of the MZI matrix. However, in Fig. 10, in order to clearly show the arrangement of the second Mach-Zehnder interferometer, Mach-Zehnder interferometers other than the second Mach-Zehnder interferometer are omitted from the MZI matrix. When the second Mach-Zehnder interferometer is operated as a second unitary matrix operation circuit in this manner, the second unitary matrix operation circuit operates as a unitary matrix operation circuit that receives seven optical signals as input and outputs seven optical signals, as shown in Fig. 10. However, in the example shown in Fig. 10, each of the hatched Mach-Zehnder interferometers M18, M28, M38, and M41 to M48 in Fig. 10 is a second Mach-Zehnder interferometer that is operated as a phase modulator (Bar state). That is, the optical intensity branching ratio of each of the hatched Mach-Zehnder interferometers M18, M28, M38, and M41 to M48 in Fig. 10 is 100:0 (Bar:Cross). On the other hand, the optical intensity branching ratio of each of the non-hatched Mach-Zehnder interferometers M11 to M17, M21 to M27, and M31 to M37 in Fig. 10 is a desired ratio according to a desired unitary matrix operation. Furthermore, of the hatched Mach-Zehnder interferometers in Fig. 10, the Mach-Zehnder interferometers M18, M28, M38, and M48 may be in a Cross state.That is, in this case, the optical intensity branching ratio in each of the Mach-Zehnder interferometers M18, M28, M38, and M48 is 0:100 in terms of Bar:Cross.

[0060] 9 and 10, when the third Mach-Zehnder interferometer is the second Mach-Zehnder interferometer and the fourth Mach-Zehnder interferometer is the first Mach-Zehnder interferometer, the control device 20 operates the optical switch circuit 10 by dividing it into two unitary matrix operation circuits. In this case, the arrangement of the Mach-Zehnder interferometers formed by overlapping the first Mach-Zehnder interferometer shown in FIG. 9 and the second Mach-Zehnder interferometer shown in FIG. 10 coincides with the arrangement of the Mach-Zehnder interferometers in the MZI matrix shown in FIG. 2.

[0061] <Variation 1 of Specific Arrangement Example> In the above-described specific examples 1 to 4, each of the four first Mach-Zehnder interferometers and the four second Mach-Zehnder interferometers included in the eighth column is a Mach-Zehnder interferometer that can be operated as a phase modulator (Bar state or Cross state). However, the control device 20 may be configured not to operate one or more of the four first Mach-Zehnder interferometers included in the eighth column as a phase modulator. Furthermore, the control device 20 may be configured not to operate one or more of the four second Mach-Zehnder interferometers included in the eighth column as a phase modulator. For example, FIG. 11 is a diagram showing Variation 1 of Specific Example 1 of the arrangement of first Mach-Zehnder interferometers that operate as a first unitary matrix calculation circuit. In the example shown in FIG. 11 , similar to the example shown in FIG. 3 , among the Mach-Zehnder interferometers operating as the first Mach-Zehnder interferometer, the Mach-Zehnder interferometer M18 included in the eighth column is operated as a phase modulator (Bar state or Cross state). The Mach-Zehnder interferometers M38, M58, and M78 have a desired ratio according to the desired unitary matrix calculation. In this case, the number of stages of the Mach-Zehnder interferometers performing the unitary matrix calculation as the first unitary matrix calculation circuit is increased from seven to eight. In this way, increasing the number of stages of the Mach-Zehnder interferometers performing the unitary matrix calculation improves the controllability of the unitary matrix calculation circuit, thereby making it possible to reduce calculation errors in the unitary matrix calculation. This situation is similar in specific examples 2 to 4 of the arrangement of the first Mach-Zehnder interferometer and specific examples 1 to 4 of the arrangement of the second Mach-Zehnder interferometer. For this reason, a description of variant 1 of these specific examples using illustrations will be omitted.

[0062] <Variation 2 of Specific Arrangement> In the specific examples 1 to 4 described above, the functions of the first column and the eighth column may be interchanged. That is, for example, in the example shown in FIG. 3 , the control device 20 may operate each of the Mach-Zehnder interferometers M12, M14, M16, M18, M21, M41, M61, M81, M83, M85, and M87 as a phase modulator. Even in this case, the control device 20 can operate the first Mach-Zehnder interferometer as a first unitary matrix calculation circuit. This also applies to other specific arrangements of the first unitary matrix calculation circuit and the second unitary matrix calculation circuit.

[0063] <Variation 3 of Specific Example of Arrangement> As described above, in the specific examples 1 to 4 described above, the arrangement of the first Mach-Zehnder interferometer when the number of optical signals input to the first unitary matrix calculation circuit and the number of optical signals output from the first unitary matrix calculation circuit are each 6 or less can be easily specified in accordance with the rule for functioning as a unitary matrix calculation circuit. Here, FIG. 12 is a diagram showing an example of the arrangement of the first Mach-Zehnder interferometer when the number of optical signals output from the first unitary matrix calculation circuit is each 6. That is, the arrangement shown in FIG. 12 is an arrangement of the first Mach-Zehnder interferometer when the number of optical signals output from the first unitary matrix calculation circuit is each 6, among the arrangements that can be specified in accordance with the rule. The first unitary matrix calculation circuit shown in FIG. 12 is a variation of the first unitary matrix calculation circuit shown in FIG. 3 and is the first unitary matrix calculation circuit when the operation of the Mach-Zehnder interferometer included in the eighth row as the first Mach-Zehnder interferometer is stopped. In the first unitary matrix operation circuit shown in FIG. 12 , the first Mach-Zehnder interferometers included in the first row, the seventh row, the seventh column, and the eighth column are operated as phase modulators (Bar state). This allows the control device 20 to set the number of optical signals input to the first unitary matrix operation circuit shown in FIG. 12 and the number of optical signals output from the first unitary matrix operation circuit to six. In this way, instead of operating the optical switch circuit 10 including 8 × 8 Mach-Zehnder interferometers as a first unitary matrix operation circuit and a second unitary matrix operation circuit that input seven optical signals and output seven optical signals, the control device 20 can operate the optical switch circuit 10 including 8 × 8 Mach-Zehnder interferometers as a first unitary matrix operation circuit and a second unitary matrix operation circuit that input six or less optical signals and output six or less optical signals. As a result, the control device 20 can improve the versatility of the optical switch circuit 10 as a unitary matrix operation circuit.

[0064] 13 is a diagram showing an example of the arrangement of the second Mach-Zehnder interferometer when the number of optical signals output from the second unitary matrix operation circuit is six. The second unitary matrix operation circuit shown in FIG. 13 is a modified example of the second unitary matrix operation circuit shown in FIG. 4, and is the second unitary matrix operation circuit when the operation of the Mach-Zehnder interferometer included in the first row as the second Mach-Zehnder interferometer is stopped. That is, the control device 20 can operate the optical switch circuit 10 as the second unitary matrix operation circuit shown in FIG. 13 by a method similar to the method for operating the optical switch circuit 10 as the first unitary matrix operation circuit shown in FIG. 12. Therefore, further detailed description of the second unitary matrix operation circuit shown in FIG. 13 will be omitted here.

[0065] <Fourth Variation of Specific Example of Arrangement> The control device 20 described above may be configured to operate as a unitary matrix calculation circuit using Mach-Zehnder interferometers included in each of two or more submatrices included in an MZI matrix, as shown in FIG. 14, for example. FIG. 14 is a diagram showing an example of how three unitary matrix calculation circuits operate within an MZI matrix. In FIG. 14, the MZI matrix has three submatrices, MX1, MX2, and MX3. The submatrices MX1, MX2, and MX3 do not overlap with each other. The submatrix MX1 is a matrix including 12 Mach-Zehnder interferometers, M11 to M13, M21 to M23, M31 to M33, and M41 to M43. The submatrix MX2 is a matrix including 12 Mach-Zehnder interferometers M51 to M53, M61 to M63, M71 to M73, and M81 to M83. The submatrix MX3 is a matrix including 30 Mach-Zehnder interferometers M14 to M18, M24 to M28, M34 to M38, M44 to M48, M54 to M58, and M64 to M68.

[0066] In the submatrix MX1, the Mach-Zehnder interferometers M12, M21, M23, M32, M41, and M43 are operated as a unitary matrix calculation circuit by the same method as described in the first specific example of arrangement. Each of the Mach-Zehnder interferometers M12, M41, and M43 is operated as a phase modulator (Bar state). Hereinafter, for convenience of explanation, the unitary matrix calculation circuit configured by the Mach-Zehnder interferometers M12, M21, M23, M32, M41, and M43 shown in FIG. 14 will be referred to as the third unitary matrix calculation circuit. The third unitary matrix calculation circuit operates as a unitary matrix calculation circuit that receives three optical signals and outputs three optical signals. However, the optical signal input to the second input port of the Mach-Zehnder interferometer M41 is not treated as an optical signal input to the third unitary matrix calculation circuit. The handling of this optical signal will be described later.

[0067] In the submatrix MX2, the Mach-Zehnder interferometers M52, M61, M63, M72, M81, and M83 are operated as a unitary matrix calculation circuit by the same method as that described in the specific example 1 of the arrangement. Each of the Mach-Zehnder interferometers M52, M81, and M83 is operated as a phase modulator (Bar state). Hereinafter, for convenience of explanation, the unitary matrix calculation circuit configured by the Mach-Zehnder interferometers M52, M61, M63, M72, M81, and M83 shown in FIG. 14 will be referred to as a fourth unitary matrix calculation circuit. The fourth unitary matrix calculation circuit operates as a unitary matrix calculation circuit that receives three optical signals and outputs three optical signals.

[0068] In the submatrix MX3, the Mach-Zehnder interferometers M14, M16, M18, M25, M27, M34, M36, M38, M45, M47, M54, M56, M58, M65, and M67 are operated as a unitary matrix calculation circuit by the same method as that described in the specific example of arrangement 1. Each of the Mach-Zehnder interferometers M14, M16, M18, M65, and M67 is operated as a phase modulator (Bar state). For convenience of explanation, the unitary matrix calculation circuit configured by the Mach-Zehnder interferometers M14, M16, M18, M25, M27, M34, M36, M38, M45, M47, M54, M56, M58, M65, and M67 shown in FIG. 14 will be referred to as a fifth unitary matrix calculation circuit in the following description. The fifth unitary matrix operation circuit operates as a unitary matrix operation circuit that receives five input optical signals and outputs five optical signals. Here, one of the five optical signals input to the fifth unitary matrix operation circuit is an optical signal input to the second input port of the Mach-Zehnder interferometer M41. This optical signal is input to the second input port of the Mach-Zehnder interferometer M41, which operates as a phase modulator, and then output from the second output port of the Mach-Zehnder interferometer M41. The optical signal is then input to the first input port of the Mach-Zehnder interferometer M52, which operates as a phase modulator in the fourth unitary matrix operation circuit, and then output from the first output port of the Mach-Zehnder interferometer M52. Further, the optical signal is input to the second input port of the Mach-Zehnder interferometer M43, which operates as a phase modulator in the third unitary matrix operation circuit, and then output from the second output port of the Mach-Zehnder interferometer M43. As a result, the optical signal is input to the fifth unitary matrix operation circuit. Therefore, the optical signal is input to the fifth unitary matrix operation circuit without being involved in the unitary matrix operations in the third unitary matrix operation circuit and the fourth unitary matrix operation circuit. Furthermore, three of the five optical signals input to the fifth unitary matrix operation circuit are the three optical signals output from the third unitary matrix operation circuit. Furthermore, one of the five optical signals input to the fifth unitary matrix operation circuit is one of the three optical signals output from the fourth unitary matrix operation circuit.As a result, the control device 20 can use the optical switch circuit 10 to sequentially perform a plurality of unitary matrix operations on a plurality of optical signals input to the optical switch circuit 10, and output a plurality of optical signals obtained as a result of the plurality of unitary matrix operations. Note that, in the example shown in Fig. 14, each of the Mach-Zehnder interferometers M74, M76, M78, M85, and M87 is operated as a phase modulator (Bar state), but this is not limited to this.

[0069] <Fifth variation of specific example of arrangement> The control device 20 can also operate the 8 × 8 Mach-Zehnder interferometers included in the MZI matrix as two unitary matrix calculation circuits: a first unitary matrix calculation circuit that performs unitary matrix calculation with eight optical signals as input and eight optical signals as output, and a second unitary matrix calculation circuit that performs unitary matrix calculation with six optical signals as input and six optical signals as output.

[0070] 15 is a diagram showing an example of an arrangement of first Mach-Zehnder interferometers when the number of optical signals input to the first unitary matrix calculation circuit is eight and the number of optical signals output from the first unitary matrix calculation circuit is eight. The first unitary matrix calculation circuit shown in FIG. 15 is a modified example of the first unitary matrix calculation circuit shown in FIG. 11 , and is a first unitary matrix calculation circuit when all eight Mach-Zehnder interferometers included in the eighth row are operated as first Mach-Zehnder interferometers. In the first unitary matrix calculation circuit shown in FIG. 15 , each of the Mach-Zehnder interferometers M12, M14, M16, M18, M82, M84, M86, and M88 is operated as a phase modulator (Bar state). This allows the control device 20 to set the number of optical signals input to the first unitary matrix calculation circuit shown in FIG. 15 and the number of optical signals output from the first unitary matrix calculation circuit to eight.

[0071] When the first Mach-Zehnder interferometer is operated as a first unitary matrix operation circuit as shown in Fig. 15, the control device 20 can operate the second Mach-Zehnder interferometer as a second unitary matrix operation circuit as shown in Fig. 13. That is, the control device 20 can also operate the 8 × 8 Mach-Zehnder interferometers included in the MZI matrix as two unitary matrix operation circuits: a first unitary matrix operation circuit that performs unitary matrix operation with eight optical signals as input and eight optical signals as output, and a second unitary matrix operation circuit that performs unitary matrix operation with six optical signals as input and six optical signals as output.

[0072] <Sixth Modification of Specific Example of Arrangement> A configuration may be adopted in which a cross waveguide CS is connected to each of the first output port and the second output port of the Mach-Zehnder interferometer included in the MZI matrix described above, as shown in Fig. 16. Fig. 16 is a diagram showing an example of an MZI matrix in which a cross waveguide CS is connected to the first output port and the second output port of each Mach-Zehnder interferometer.

[0073] The crossing waveguide CS connected to the first and second output ports of a Mach-Zehnder interferometer is a waveguide that switches the output destination of the first output port with the output destination of the second output port. The crossing waveguide CS may have a known configuration or a configuration to be developed in the future.

[0074] 16, the optical switch circuit 10 has a wider operating wavelength band as a PILOSS optical switch circuit. This means that the versatility of the optical switch circuit 10 can be further improved.

[0075] Moreover, when the MZI matrix has a configuration as shown in Fig. 16, for example, the first Mach-Zehnder interferometer operating as the first unitary matrix calculation circuit shown in Fig. 3 is arranged in the MZI matrix as shown in Fig. 17. Fig. 17 is a diagram showing an example of how the cross waveguides CS are connected to each of the first Mach-Zehnder interferometers shown in Fig. 3. The first unitary matrix calculation circuit in which the first Mach-Zehnder interferometers are arranged as shown in Fig. 17 can also perform unitary matrix calculations, similar to the first unitary matrix calculation circuit shown in Fig. 3.

[0076] The optical switch circuit 10 may also be configured to include various devices (e.g., a phase modulator, an optical branching device, an optical power monitor, etc.) provided at desired positions among the positions through which an optical signal propagates within the optical switch circuit 10. For example, a phase modulator may be provided at the input port of the Mach-Zehnder interferometer in the first row of the optical switch circuit 10. This is because it is expected to improve the controllability of the circuit and reduce operational errors in the operation of the optical switch circuit 10 as an optical switch and a unitary matrix operation circuit.

[0077] <Configuration of Control Device> The configuration of the control device 20 will be described below with reference to Fig. 18. Fig. 18 is a diagram showing an example of the configuration of the control device 20.

[0078] The control device 20 includes a control unit 21 , a storage unit 22 , an input receiving unit 23 , a communication unit 24 , and a display unit 25 .

[0079] The control unit 21 controls the entire control device 20. The control unit 21 includes a processor such as a CPU or FPGA, for example.

[0080] The storage unit 22 is a storage device and includes, for example, a random access memory (RAM), a read only memory (ROM), a solid state drive (SSD), etc. The storage unit 22 may be an external storage device connected from the outside.

[0081] The input acceptance unit 23 is an input device including a keyboard, a mouse, a touchpad, a lever, buttons, etc. The input acceptance unit 23 may be a touch panel integrated with the display unit 25. The control device 20 may also be configured without the input acceptance unit 23. In this case, the control device 20 is operated by an information processing device or the like connected from the outside.

[0082] The communication unit 24 is a communication device that includes an antenna for wireless communication and various ports for wired communication.

[0083] The display unit 25 is a display device configured to include a display. The control device 20 may also be configured not to include the display unit 25. In this case, the control device 20 may be configured to be connected to an external display device or not to be connected to an external display device.

[0084] <Process for Operating the Optical Switch Circuit as a Unitary Matrix Operation Circuit> Hereinafter, with reference to FIG. 19 , a process for operating the optical switch circuit 10 as a unitary matrix operation circuit, among the operations performed by the control device 20, will be described. FIG. 19 is a diagram showing an example of the flow of a process for operating the optical switch circuit 10 as a unitary matrix operation circuit, among the operations performed by the control device 20. Below, as an example, a case will be described in which the control device 20 operates the optical switch circuit 10 as two unitary matrix operation circuits, namely, a first unitary matrix operation circuit and a second unitary matrix operation circuit. Below, as an example, a case will be described in which the first information and the second information are stored in advance in the storage unit 22 at a timing before the processing of step S110 shown in FIG. 19 is performed. The first information is information including first operation method information indicating an operation method for each of the plurality of first Mach-Zehnder interferometers. For example, the first information includes first identification information for identifying a Mach-Zehnder interferometer to be operated as a first Mach-Zehnder interferometer among the 8 × 8 Mach-Zehnder interferometers and first operation method information for each Mach-Zehnder interferometer identified by the first identification information. Here, the operation method of the first Mach-Zehnder interferometer is represented, for example, by an optical intensity branching ratio, a phase modulation amount, etc. In this case, the first operation method information for a certain Mach-Zehnder interferometer to be operated as the first Mach-Zehnder interferometer includes, for example, information indicating the optical intensity branching ratio and the phase modulation amount of the Mach-Zehnder interferometer. This allows the control device 20 to identify how to operate each Mach-Zehnder interferometer operating as a first Mach-Zehnder interferometer. The second information includes second operation method information indicating the operation method of each of the plurality of second Mach-Zehnder interferometers. For example, the second information includes second identification information for identifying a Mach-Zehnder interferometer to be operated as the second Mach-Zehnder interferometer among the 8 × 8 Mach-Zehnder interferometers, and second operation method information for each Mach-Zehnder interferometer identified by the second identification information. Here, the operation method of the second Mach-Zehnder interferometer is represented by, for example, an optical intensity branching ratio, a phase modulation amount, or the like.In this case, the second operation method information for a certain Mach-Zehnder interferometer to be operated as the second Mach-Zehnder interferometer includes, for example, information indicating the optical intensity branching ratio and the phase modulation amount of the Mach-Zehnder interferometer. This allows the control device 20 to identify how to operate each Mach-Zehnder interferometer operating as the second Mach-Zehnder interferometer. In addition, hereinafter, as an example, a case will be described in which the control device 20 receives a first start operation to start operating the optical switch circuit 10 as a unitary matrix operation circuit at that timing.

[0085] After receiving the first start operation, the control unit 21 reads out from the storage unit 22 the first information and the second information that are pre-stored in the storage unit 22 (step S110).

[0086] Next, the control unit 21 specifies operation methods of the first Mach-Zehnder interferometer and the second Mach-Zehnder interferometer (step S120). In FIG. 19 , the processing of step S120 is indicated by "specifying operation methods of the first MZI and the second MZI." Here, the processing of step S120 will be described. The control unit 21 performs the following processing in step S120. Based on the first information read out from the storage unit 22 in step S110, the control unit 21 specifies a Mach-Zehnder interferometer to be operated as the first Mach-Zehnder interferometer among the MZI matrixes. Then, based on the first information, the control unit 21 specifies an operation method for each of the specified Mach-Zehnder interferometers. Meanwhile, based on the second information read out from the storage unit 22 in step S110, the control unit 21 specifies a Mach-Zehnder interferometer to be operated as the second Mach-Zehnder interferometer among the MZI matrixes. Then, the control unit 21 specifies the operation method for each of the specified Mach-Zehnder interferometers based on the second information. The control unit 21 performs the above process in step S120.

[0087] Next, the control unit 21 causes the optical switch circuit 10 to start operating as a first unitary matrix calculation circuit and a second unitary matrix calculation circuit based on the operation method of each first Mach-Zehnder interferometer and the operation method of each second Mach-Zehnder interferometer identified in step S120 (step S130). In Fig. 19, the processing of step S130 is indicated by "start of operation of first MZI and second MZI".

[0088] Next, the control unit 21 waits until the unitary matrix operation by the first unitary matrix operation circuit and the unitary matrix operation by the second unitary matrix operation circuit are each completed (step S140). Note that the method by which the control unit 21 determines whether the unitary matrix operation by the first unitary matrix operation circuit and the unitary matrix operation by the second unitary matrix operation circuit are each completed may be a known method or a method to be developed in the future. Therefore, in this embodiment, a detailed description of the method by which the control unit 21 determines whether the unitary matrix operation by the first unitary matrix operation circuit and the unitary matrix operation by the second unitary matrix operation circuit are each completed will be omitted.

[0089] If the control unit 21 determines that the unitary matrix operation by the first unitary matrix operation circuit and the unitary matrix operation by the second unitary matrix operation circuit have both been completed (step S140-YES), it causes the optical switch circuit 10 to terminate the operation of the optical switch circuit 10 as the first unitary matrix operation circuit and the second unitary matrix operation circuit that began in step S130 (step S150), and terminates the processing of the flowchart shown in Figure 19.

[0090] As described above, the control device 20 can operate the optical switch circuit 10, which includes 8×8 Mach-Zehnder interferometers arranged in an 8-row, 8-column matrix, as two unitary matrix operation circuits. This allows the control device 20 to manufacture the optical switch circuit and the unitary matrix operation circuit as a single optical circuit. As a result, the control device 20 can reduce the costs required for manufacturing and using the optical circuits.

[0091] <Process for Operating the Optical Switch Circuit as a PILOSS Optical Switch Circuit> Hereinafter, with reference to FIG. 20 , a process for operating the optical switch circuit 10 as a PILOSS optical switch circuit, among the operations performed by the control device 20, will be described. FIG. 20 is a diagram showing an example of the flow of a process for operating the optical switch circuit 10 as a PILOSS optical switch circuit, among the operations performed by the control device 20. Below, as an example, a case will be described in which the 0th information is pre-stored in the storage unit 22 at a timing before the processing of step S110 shown in FIG. 20 is performed. The 0th information is information including 0th operation method information indicating an operation method for each of the 8×8 Mach-Zehnder interferometers. For example, the 0th information is information including 0th identification information that identifies the 8×8 Mach-Zehnder interferometers and 0th operation method information for each Mach-Zehnder interferometer identified by the 0th identification information. Here, the operation method of these Mach-Zehnder interferometers is represented, for example, by an optical intensity branching ratio or the like. In this case, the 0th operation method information for a certain Mach-Zehnder interferometer includes, for example, information indicating the optical intensity branching ratio of the Mach-Zehnder interferometer. This allows the control device 20 to identify how to operate each Mach-Zehnder interferometer operating as a PILOSS optical switch circuit. In the following, as an example, a case will be described in which the control device 20 receives a second start operation to start operating the optical switch circuit 10 as a PILOSS optical switch circuit at a certain timing.

[0092] After receiving the second start operation, the control unit 21 reads out the 0th information stored in advance in the storage unit 22 from the storage unit 22 (step S210).

[0093] Next, the control unit 21 identifies the operation methods of all Mach-Zehnder interferometers included in the MZI matrix (step S220). In FIG. 20 , the processing of step S220 is indicated by "identifying operation methods of all MZIs." Here, the processing of step S220 will be described. The control unit 21 performs the following processing in step S220. The control unit 21 identifies all Mach-Zehnder interferometers included in the MZI matrix based on the 0th information read out from the storage unit 22 in step S210. Then, the control unit 21 identifies the operation method of each of the identified Mach-Zehnder interferometers based on the 0th information. The control unit 21 performs the above processing in step S220.

[0094] Next, the control unit 21 causes the optical switch circuit 10 to start operating as a PILOSS optical switch circuit based on the operation method of each Mach-Zehnder interferometer identified in step S220 (step S230). In Fig. 20, the processing of step S230 is indicated by "start operation of all MZIs."

[0095] Next, the control unit 21 waits until the optical switch circuit 10 operating as a PILOSS optical switch circuit has completed switching of the optical signal (step S240). The method by which the control unit 21 determines whether the switching has completed may be a known method or a method to be developed in the future. Therefore, in this embodiment, a detailed description of the method by which the control unit 21 determines whether the switching has completed will be omitted.

[0096] If the control unit 21 determines that the switching of the optical signal by the optical switch circuit 10 operating as a PILOSS optical switch circuit has been completed (step S240-YES), it causes the optical switch circuit 10 to terminate the operation of the optical switch circuit 10 as a PILOSS optical switch circuit that began in step S230 (step S250), and terminates the processing of the flowchart shown in Figure 20.

[0097] As described above, when the control device 20 is not operating the optical switch circuit 10 as a unitary matrix operation circuit, it can operate the optical switch circuit 10 as a PILOSS optical switch circuit.

[0098] The above-described contents may be combined in any manner.

[0099] As described above, the control device according to the embodiment (control device 20 in the example described above) includes a control unit (control unit 21 in the example described above) that can operate an optical switch circuit (optical switch circuit 10 in the example described above) including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer equal to or greater than 8 (N is 8 in the example described above), as two or more unitary matrix operation circuits (for example, a first unitary matrix operation circuit and a second unitary matrix operation circuit, etc.) where N is an integer equal to or greater than 8 (N is 8 in the example described above). This enables the control device to reduce costs required for manufacturing and using the optical circuits.

[0100] Note that unitary matrix calculations are analog calculations. Therefore, the effects of manufacturing errors in the unitary matrix calculation circuit are reflected in the results of the unitary matrix calculations performed by the unitary matrix calculation circuit. This means that the results depend on the manufacturing errors. In contrast, the control method using the control device 20 can operate the optical switch circuit 10 as two or more unitary matrix calculation circuits, allowing the same unitary matrix calculation to be performed using the two or more unitary matrix calculation circuits. By comparing the results of unitary matrix calculations using different Mach-Zehnder interferometers, the influence of the manufacturing errors on the calculation errors can be analyzed and reduced. Furthermore, as shown in specific examples 1 to 4, the same unitary matrix calculation can be performed using different arrangements of Mach-Zehnder interferometers. By comparing the results of unitary matrix calculations using different combinations of Mach-Zehnder interferometers, the influence of the manufacturing errors on the calculation errors can be analyzed and reduced.

[0101] Furthermore, the input light used as the optical signal described above may be laser light, quantum light, or other light.

[0102] Expectations for optical circuits such as the optical switch circuit 10 according to the present embodiment are expected to grow in the future from the viewpoint of high speed and low power consumption. However, challenges for practical application include cost reduction and supply chain development. Therefore, the control device according to the present disclosure can unify materials, production lines, manufacturing technologies, production management, etc., and reduce costs for optical circuits. Therefore, it can be said that the control device according to the present disclosure has great potential for practical use in industry.

[0103] <Notes> [1] A control device comprising a control unit capable of operating an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer greater than or equal to 8, as two or more unitary matrix operation circuits. [2] The control device according to [1], wherein the two or more unitary matrix operation circuits include a first unitary matrix operation circuit and a second unitary matrix operation circuit different from the first unitary matrix operation circuit, the N×N Mach-Zehnder interferometers include a plurality of first Mach-Zehnder interferometers operating as the first unitary matrix operation circuits and a plurality of second Mach-Zehnder interferometers operating as the second unitary matrix operation circuits, the control device comprises a storage unit that stores first information including information indicating an operation method of each of the plurality of first Mach-Zehnder interferometers and second information including information indicating an operation method of each of the plurality of second Mach-Zehnder interferometers, and the control unit operates the plurality of first Mach-Zehnder interferometers as the first unitary matrix operation circuits based on the first information stored in the storage unit, and operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix operation circuits based on the second information stored in the storage unit. [3] The control device according to [2], wherein the control unit operates some of the plurality of first Mach-Zehnder interferometers as phase modulators and some of the plurality of second Mach-Zehnder interferometers as phase modulators.[4] The control unit controls the plurality of first Mach-Zehnder interferometers to be arranged at the first unit such that, in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes a plurality of first rows in which the first Mach-Zehnder interferometer and a third Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers are alternately positioned, the plurality of first rows are arranged consecutively in a column direction of the matrix, and the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of first rows arranged consecutively in the column direction. the control device according to [2], wherein the control device operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix calculation circuit, and the matrix includes a plurality of second rows in which the second Mach-Zehnder interferometer and a fourth Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers are alternately positioned, the plurality of second rows are arranged continuously in the column direction, and the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are arranged alternately in any column included in the plurality of second rows arranged continuously in the column direction.[5] The control unit controls the control unit to arrange the plurality of first Mach-Zehnder interferometers in the first unit such that, in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes a plurality of first rows in which the first Mach-Zehnder interferometer and a third Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers are alternately positioned, and one third row in which N of the first Mach-Zehnder interferometers are arranged, the plurality of first rows are arranged consecutively in a column direction of the matrix, the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are arranged alternately in any column included in the plurality of first rows arranged consecutively in the column direction, and one third row is adjacent to one of two first rows located at both ends in the column direction among the plurality of first rows. the control device according to [2], wherein the control device operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix calculation circuit, and the matrix includes a plurality of second rows in which the second Mach-Zehnder interferometer and a fourth Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers are alternately positioned, and one fourth row in which N of the second Mach-Zehnder interferometers are aligned, the plurality of second rows are aligned continuously in the column direction, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are aligned alternately in any column included in the plurality of second rows aligned continuously in the column direction, and one of two second rows located at both ends in the column direction among the plurality of second rows is adjacent to the one fourth row.[6] The control unit controls the control unit to arrange the plurality of first Mach-Zehnder interferometers in the first unit such that, in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes a plurality of first rows in which the first Mach-Zehnder interferometer and a third Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers are alternately positioned, and a plurality of third rows in which N of the first Mach-Zehnder interferometers are arranged, the plurality of first rows are arranged consecutively in a column direction of the matrix, the plurality of third rows are arranged consecutively in the column direction, the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are arranged alternately in any column included in the plurality of first rows arranged consecutively in the column direction, and any of two first rows located at both ends in the column direction among the plurality of first rows is adjacent to the plurality of third rows. the control device operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix calculation circuit, and the matrix includes a plurality of second rows in which the second Mach-Zehnder interferometer and a fourth Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers are alternately positioned, and a plurality of fourth rows in which N of the second Mach-Zehnder interferometers are arranged, the plurality of second rows are arranged continuously in the column direction, the plurality of fourth rows are arranged continuously in the column direction, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are arranged alternately in any column included in the plurality of second rows arranged continuously in the column direction, and any of two second rows located at both ends in the column direction among the plurality of second rows is adjacent to the plurality of fourth rows.[7] The control device according to any one of [4] to [7], wherein the control unit operates the plurality of first Mach-Zehnder interferometers as the first unitary matrix calculation circuit so that a matrix formed by the N×N Mach-Zehnder interferometers includes a plurality of third rows, each including N first Mach-Zehnder interferometers arranged, and the plurality of third rows are arranged consecutively in the column direction, and operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix calculation circuit so that the matrix includes a plurality of fourth rows, each including N second Mach-Zehnder interferometers arranged, and the plurality of fourth rows are arranged consecutively in the column direction. [8] The control device according to any one of [4] to [7], wherein at least some of the plurality of third Mach-Zehnder interferometers included in the N×N Mach-Zehnder interferometers are the second Mach-Zehnder interferometers, and at least some of the plurality of fourth Mach-Zehnder interferometers included in the N×N Mach-Zehnder interferometers are the first Mach-Zehnder interferometers. [9] The control device according to any one of [2] to [8], wherein the control unit sets some of the plurality of Mach-Zehnder interferometers included in a first submatrix of a matrix formed by the N×N Mach-Zehnder interferometers as the plurality of first Mach-Zehnder interferometers, and operates the plurality of first Mach-Zehnder interferometers as the first unitary matrix calculation circuit, and sets some of the plurality of Mach-Zehnder interferometers included in a second submatrix of the matrix formed by the N×N Mach-Zehnder interferometers as the plurality of second Mach-Zehnder interferometers, and operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix calculation circuit, wherein the first submatrix and the second submatrix do not overlap.

[10] A control method for operating an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer greater than or equal to 8, as two or more unitary matrix operation circuits.

[11] A program for causing a computer to operate an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer greater than or equal to 8, as two or more unitary matrix operation circuits.

[0104] The embodiments of this disclosure have been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment, and may be changed, substituted, deleted, etc. as long as it does not deviate from the gist of this disclosure.

[0105] Furthermore, a program for implementing the functions of any of the components of the above-described device may be recorded on a computer-readable recording medium and then loaded and executed by a computer system. Here, the device in question is, for example, the control device 20. Note that the term "computer system" here includes hardware such as an operating system (OS) and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and compact disks (CDs)-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" also includes devices that retain a program for a certain period of time, such as volatile memory within a computer system that acts as a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line.

[0106] The above program may also be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network such as the Internet or a communication line such as a telephone line. The above program may also be intended to realize some of the above-mentioned functions. Furthermore, the above program may be a so-called differential file or differential program that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0107] DESCRIPTION OF SYMBOLS 1...control system, 10...optical switch circuit, 20...control device, 21...control unit, 22...storage unit, 23...input reception unit, 24...communication unit, 25...display unit, CS...intersecting waveguide, M11 to M18, M21 to M28, M31 to M38, M41 to M48, M51 to M58, M61 to M68, M71 to M78, M81 to M88...Mach-Zehnder interferometer

Claims

1. A control device comprising a control unit capable of operating an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer of 8 or greater, as two or more unitary matrix arithmetic circuits.

2. The control device according to claim 1, wherein the two or more unitary matrix calculation circuits include a first unitary matrix calculation circuit and a second unitary matrix calculation circuit different from the first unitary matrix calculation circuit, the N x N Mach-Zehnder interferometers include a plurality of first Mach-Zehnder interferometers operating as the first unitary matrix calculation circuit and a plurality of second Mach-Zehnder interferometers operating as the second unitary matrix calculation circuit, the control device comprises a memory unit that stores first information including information indicating an operation method of each of the plurality of first Mach-Zehnder interferometers and second information including information indicating an operation method of each of the plurality of second Mach-Zehnder interferometers, and the control unit operates the plurality of first Mach-Zehnder interferometers as the first unitary matrix calculation circuit based on the first information stored in the memory unit, and operates the plurality of second Mach-Zehnder interferometers as the second unitary matrix calculation circuit based on the second information stored in the memory unit.

3. The control device according to claim 2, wherein the control unit operates some of the plurality of first Mach-Zehnder interferometers as phase modulators and operates some of the plurality of second Mach-Zehnder interferometers as phase modulators.

4. The control unit controls the plurality of first Mach-Zehnder interferometers so that, in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes a plurality of first rows in which a third Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers and the first Mach-Zehnder interferometer are alternately positioned, the plurality of first rows are continuously arranged in a column direction of the matrix, and the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of first rows continuously arranged in the column direction.

3. The control device according to claim 2, wherein the control device operates as the first unitary matrix calculation circuit, and the plurality of second Mach-Zehnder interferometers operate as the second unitary matrix calculation circuit such that the matrix includes a plurality of second rows in which a fourth Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers and the second Mach-Zehnder interferometer are alternately positioned, the plurality of second rows are arranged continuously in the column direction, and the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of second rows arranged continuously in the column direction.

5. The control unit controls the plurality of first Mach-Zehnder interferometers so that, in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes a plurality of first rows in which a third Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers and the first Mach-Zehnder interferometer are alternately positioned, and one third row in which N of the first Mach-Zehnder interferometers are aligned, the plurality of first rows are aligned continuously in a column direction of the matrix, the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of first rows aligned continuously in the column direction, and one of two first rows located at both ends in the column direction among the plurality of first rows is adjacent to the one third row.

3. The control device according to claim 2, wherein the control device operates as the first unitary matrix calculation circuit, and the plurality of second Mach-Zehnder interferometers operate as the second unitary matrix calculation circuit such that the matrix includes a plurality of second rows in which a fourth Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers and the second Mach-Zehnder interferometer are alternately positioned, and a fourth row in which N of the second Mach-Zehnder interferometers are arranged, the plurality of second rows are arranged continuously in the column direction, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of second rows arranged continuously in the column direction, and one of two second rows located at both ends in the column direction among the plurality of second rows is adjacent to the one fourth row.

6. The control unit controls the plurality of first Mach-Zehnder interferometers so that, in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes a plurality of first rows in which a third Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the first Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometers and the first Mach-Zehnder interferometer are alternately positioned, and a plurality of third rows in which the N first Mach-Zehnder interferometers are arranged, the plurality of first rows are arranged continuously in a column direction of the matrix, the plurality of third rows are arranged continuously in the column direction, the third Mach-Zehnder interferometer and the first Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of first rows arranged continuously in the column direction, and any of two first rows located at both ends in the column direction among the plurality of first rows is adjacent to the plurality of third rows.

3. The control device according to claim 2, wherein the control device operates as the first unitary matrix calculation circuit, and the plurality of second Mach-Zehnder interferometers operate as the second unitary matrix calculation circuit such that the matrix includes a plurality of second rows in which a fourth Mach-Zehnder interferometer that is a Mach-Zehnder interferometer other than the second Mach-Zehnder interferometer among the N×N Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned, and a plurality of fourth rows in which the N second Mach-Zehnder interferometers are arranged, the plurality of second rows are arranged continuously in the column direction, the plurality of fourth rows are arranged continuously in the column direction, the fourth Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are alternately positioned in any column included in the plurality of second rows arranged continuously in the column direction, and any of two second rows located at both ends in the column direction among the plurality of second rows is adjacent to the plurality of fourth rows.

7. The control device according to claim 2, wherein the control unit operates the multiple first Mach-Zehnder interferometers as the first unitary matrix calculation circuit so that in a matrix formed by the N×N Mach-Zehnder interferometers, the matrix includes multiple third rows in which N of the first Mach-Zehnder interferometers are arranged, and the multiple third rows are arranged consecutively in the column direction of the matrix, and operates the multiple second Mach-Zehnder interferometers as the second unitary matrix calculation circuit so that the matrix includes multiple fourth rows in which N of the second Mach-Zehnder interferometers are arranged, and the multiple fourth rows are arranged consecutively in the column direction.

8. The control device according to any one of claims 4 to 6, wherein at least a portion of the multiple third Mach-Zehnder interferometers included in the N x N Mach-Zehnder interferometers are the second Mach-Zehnder interferometers, and at least a portion of the multiple fourth Mach-Zehnder interferometers included in the N x N Mach-Zehnder interferometers are the first Mach-Zehnder interferometers.

9. The control device according to claim 2, wherein the control unit sets some of a plurality of Mach Zehnder interferometers included in a first submatrix of a matrix formed by the N×N Mach Zehnder interferometers among the N×N Mach Zehnder interferometers as the plurality of first Mach Zehnder interferometers and operates the plurality of first Mach Zehnder interferometers as the first unitary matrix calculation circuit, sets some of a plurality of Mach Zehnder interferometers included in a second submatrix of a matrix formed by the N×N Mach Zehnder interferometers among the N×N Mach Zehnder interferometers as the plurality of second Mach Zehnder interferometers and operates the plurality of second Mach Zehnder interferometers as the second unitary matrix calculation circuit, and the first submatrix and the second submatrix do not overlap.

10. A control method for operating an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer of 8 or greater, as a unitary matrix arithmetic circuit of 2 or more.

11. A program for causing a computer to operate an optical switch circuit including N×N Mach-Zehnder interferometers arranged in a matrix of N rows and N columns, where N is an integer of 8 or greater, as a unitary matrix operation circuit of 2 or more.

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