JPH0795631A - Optical matrix switch - Google Patents

Abstract

PURPOSE:To reduce the accumulation of crosstalk by distributing the optical signals of different wavelengths supplied through the input ports to the output ports in optional combinations together with multiplexing of wavelengths by means of an M-input/N-output optical, matrix switch. CONSTITUTION:Three 2-input/2-output unit switches 1011-1013 are placed side by side in the row direction, and a 1-input/ 2-output optical switch 11 of the switch 1012 corresponding to an output port 322 is set at the side of output (b). Other switches 11 are set at the side of output (a) where the optical signals travel straight. Thus the optical signals supplied through an input port 311 are transmitted to the port 322 via the 2-input/2-output unit switches 1011, 1022, 1022 and 1042. The switch 1011 sends the received optical signals to the switch 1012 from an output terminal (a) of the switch 11 via an output line 1. The switch 1012 transmits the received optical signals through an output terminal (b) of the switch 11. These signals are reflected by an optical filter 12 and sent to the switch 1022 via an output line 2 (circle mark). Thus the optical signals are transmitted through the filter 12 and sent to the switch 1032 via the line 2. The filter 12 multiplexes the light beams traveling to the same output port and sends them to the port 322.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical matrix switch used for optical signal exchange processing. In particular, the present invention relates to an optical matrix switch used for exchanging optical signals of different wavelengths transmitted by a wavelength division multiplexing communication system.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration example of a conventional optical matrix switch. In addition, here, the literature (Okuno, Sugita,
Matsunaga, Kawauchi, "Wavelength characteristics of silica-based thermo-optic 8x8 matrix switch", 1-17 Autumn Meeting of IEICE C-17
The one described in 1) is shown in a simplified manner in a 4 × 4 configuration.

[0003] In the figure, four input ports 31 _1-3
1 ₄ and 4 output ports 32 _{1 to} 32 ₄ are 16 2
The input and output optical switches 40 ₁₁ to 40 ₄₄ are combined in a matrix. Optical signals of the same wavelength are input to each input port.

FIG. 5 shows a configuration example of the 2-input 2-output optical switch 40. In the figure, a 2-input 2-output optical switch 40
Is a 2-input 2-output Maha-Zehnder interferometer type switch. That is, the 3 dB coupler 4 connected to the input waveguides 41 _{1 and} 41 ₂ and the output waveguides 42 _{1 and} 42 _2.
This is a configuration in which the thermo-optical phase shifter 44 for setting the phase difference is arranged on 3 _1, 43 ₂ and two links between them. By setting a predetermined phase difference with the thermo-optical phase shifter 44, the two optical signals input from the input waveguides 41 _1, 41 ₂ are output to the output waveguides 42 ₂ , 42 ₁ with their spatial positions switched. (Crossed state) or the output waveguide 42 _1,
42 ₂ can be output (bar state). That is, the 2-input 2-output optical switch 40 can be operated as a space switch.

The optical matrix switch shown in FIG. 4 is a combination of the 2-input 2-output optical switch 40 in a matrix form. That is, the output waveguides 4 of the two-input, two-output optical switches (for example, 40 ₁₁ , 40 ₁₂ ) adjacent to each other on the left and right
2 ₁ and the input waveguide 41 ₂ are coupled to each other, and the output waveguides 42 ₂ and the input waveguides 41 ₁ of the vertically adjacent two-input two-output optical switches (eg 40 ₁₁ and 40 ₂₁ ) are coupled to each other. Further, each input waveguide 41 ₂ of the left end of the 2-input 2 output optical switch 40 _{11-40 41} and the input port 31 ₁ to 31 _4, each of the output waveguides of the 2-input 2 output optical switch 40 _{41-40 44} at the lower end 42
Let ₁ be the output ports 32 _{1 to} 32 ₄ . This allows the optical matrix switch shown in FIG. 4 to function as a 4-input 4-output space switch.

[0006]

By the way, in order to perform exchange processing of optical signals of different wavelengths transmitted by the wavelength division multiplexing communication system, a 2-input 2-output optical switch 40 for switching optical signals of the same wavelength is used. It cannot be used as it is as a basic element. To switch optical signals with different wavelengths, ₂ dB between the 3 dB couplers 43 _{1 and} 43 ₂ is used.
A predetermined path length difference is set for a book link and the wavelength demultiplexing function is used.

However, since such an optical switch also functions as a space switch, it is not possible to distribute optical signals of different wavelengths input to the respective input waveguides to the same output waveguide. That is, in the optical matrix switch having the configuration shown in FIG. 4, it is not possible to distribute optical signals of different wavelengths input to the respective input ports to the respective output ports in an arbitrary combination. In order to realize it, an M input (M × N) output optical matrix switch is configured, and the output waveguides of the (M × N) optical matrix switches are merged every M to form an output port. It is necessary to have a 2-input 2-output optical switch (M ×
It was necessary to prepare M × N) pieces.

In the 2-input 2-output optical switch, crosstalk occurs between the optical signals output to the two output waveguides in either the cross state or the bar state. In the optical matrix switch in which the two-input and two-output optical switches are combined in a matrix, crosstalk is accumulated, and the difference in the intensity (SN ratio) between the optical signal and the crosstalk light becomes small according to the scale, making signal discrimination difficult. become.

Generally, the signal-to-crosstalk ratio SXR of a matrix switch having N switch stages is SXR = X−10log ₁₀ (N−1) [dB] where X is the average crosstalk per optical switch. Given (H.Okayama, A.Matoba, R.Shibuya, T.Is
hida, "Optical Switch Matrix with Simplified N × NT
ree Structure ", IEEE Journal of LightwaveTechnolo
gy vol.7, No.7, pp.1023-1028, 1989). Therefore, 8 ×
The 8-matrix switch has 15 switch stages, which causes deterioration of about 11 dB, and the 16 × 16 matrix switch has 31 switch stages, which causes deterioration of about 15 dB. In addition, according to the above-mentioned literature, the value of crosstalk is -20 dB on average for each 2-input 2-output optical switch.
Therefore, the SN ratio of the 8 × 8 matrix switch is about 9 dB, and the SN ratio of the 16 × 16 matrix switch is
The ratio becomes about 5 dB. As described above, as the scale of the optical matrix switch increases, it becomes difficult to process a high-speed optical signal.

According to the present invention, an optical switch having as few optical switches as possible can be used to distribute optical signals of different wavelengths input to the respective input ports to the respective output ports in any combination, and the amount of accumulated crosstalk is small. It is intended to provide a matrix switch.

[0011]

An optical matrix switch of the present invention comprises first and second input lines to which an optical signal is input, and a 1-input 2-output optical switch connected to the first input line. A first output line connected to one output of the one-input two-output optical switch, and an optical filter for joining the optical signal of the other output of the one-input two-output optical switch and the optical signal of the second input line, The second output line connected to the output of the optical filter is a 2-input 2-output unit switch of 1 unit, and the 2-input 2-output unit switch is arranged in M rows and N columns, and 2 inputs of each column are arranged in a matrix. The first output line and the first input line of the 2-output unit switch, and the second output line and the second input line of the 2-input 2-output unit switch of each row are connected, and the M of the first column is connected.
The first input lines of the two 2-input 2-output unit switches are respectively connected to the M input ports, and the N 2-input 2 of the M-th row are connected.
N output ports are connected to the second output line of the output unit switch to form an M input N output switch configuration.

[0012]

The optical matrix switch of the present invention has a structure in which 2-input 2-output unit switches are arranged at the intersections of the M × N matrix. An optical signal input from one of the M input ports is selected by one of N 2-input 2-output unit switches corresponding to each output port cascaded in the row direction, and is selected through the optical filter. 2 inputs 2 from the second output line to the next line
It is sent to the output unit switch. In the 2-input 2-output unit switch in the next row, the optical signal input from the second input line is sent to the 2-input 2-output unit switch in the next row via the optical filter and the second output line. Similarly, the optical signal is transmitted to the output port after passing through the 2-input 2-output unit switches arranged in the column direction.

With such a configuration, it is possible to distribute optical signals of different wavelengths input to the respective input ports to the respective output ports in any combination. For example,
It is also possible to wavelength-multiplex optical signals input from different input ports i and j to the same output port k and send them out. At this time, wavelength division multiplexing of both optical signals is performed by the optical filter of the 2-input 2-output unit switch in the j-th row and the k-th column.

Further, in the 2-input 2-output optical switch, crosstalk appears mutually, but in the 1-input 2-output optical switch, since one optical signal is input, crosstalk due to switching also appears on the non-switching side. Only. Moreover, the crosstalk generated on the output port side from the 1-input 2-output optical switch of each 2-input 2-output unit switch does not depend on the number of 2-input 2-output unit switches arranged in the row direction. Therefore, the crosstalk appearing at each output port is only the added value of the crosstalk in the 2-input 2-output unit switch arranged in the column direction at the maximum, and the crosstalk accumulation can be effectively and significantly reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a first embodiment of the present invention.
Here, the number of input ports M is 4, and the number of output ports N
However, the number of input ports and the number of output ports can both be arbitrarily set.

[0016] In the figure, four input ports 31 _1-3
1 ₄ and three output ports 321 _to 323 in the _third intersection, two inputs and two outputs unit switches 10 _11-1, which is a feature of the present invention
Place 0 ₄₃ . Each 2-input 2-output unit switch 10
Input line, 1-input 2-output optical switch 11 connected to the input line, and output a of 1-input 2-output optical switch 11
Output line connected to and the 1-input 2-output optical switch 11
The optical filter 12 that joins the optical signal of the output b and the optical signal of the input line, and the output line connected to the output of the optical filter 12.

First row 2-input 2-output unit switch 10 ₁₁
10 each input port 31 of each input line of _{41 1-3}
1 ₄ and each input line is connected to each input line of the second input 2-output unit switch 10 ₁₂ to 10 ₄₂ in the second column. In the same manner, cascade connection is made in columns. The input lines of the 2-input 2-output unit switches 10 ₂₁ to 10 ₂₃ in the second row are connected to the output lines of the 2-input 2-output unit switches 10 ₁₁ to 10 ₁₃ in the first row. Similarly, the output lines of the second input / output unit switches 10 ₄₁ to 10 ₄₃ in the fourth row will be referred to as output ports 32 _{1 to} 32 _{3 in the} same manner.

1-input 2-output optical switch 11 of this embodiment
Uses a Maha-Zehnder interferometer type switch having a wavelength demultiplexing function with one input and two outputs. Alternatively, if it can operate in the wavelength band used, use an optical switch or waveguide switch that uses a semiconductor, or a gate switch that uses an element that can control the passage or blocking of light, such as a liquid crystal or an acousto-optic device. Can be used.

The optical filter 12 uses an element that transmits or reflects light according to the wavelength of the optical signal. For example, an acousto-optic filter using an acousto-optic element, a Maha-Zehnder filter using a Maha-Zehnder interferometer, a dielectric multilayer film filter, or the like can be used. The function is that the optical signal of the output b of the 1-input 2-output optical switch 11 is reflected to the output port side and the optical signal of the input line is transmitted to the output port side, thereby wavelength-multiplexing the optical signals going to the same output port. To do. In wavelength multiplexing using the optical filter 12, no merging loss occurs in principle.

In the configuration of this embodiment, each input port 31 ₁
It is in principle for inputting an optical signal having a wavelength different to 31 _4. Note that optical signals of the same wavelength may be input from different input ports as long as they are not output to the same output port. Below, specific examples based on the principle will be shown.

Input ports 31 ₁ , 31 ₂ , 31 ₃ , 31
The wavelength of the optical signal input to ₄ is λ according to the arrangement on the wavelength axis.
Let ₁ , λ ₂ , λ ₃ , and λ ₄ . At this time, the optical filter 12 mounted on the 2-input 2-output unit switch 10 of each row
2 has the characteristics shown in FIGS. 2 (1) to 2 (4).

That is, the optical filters 12 of the 2-input 2-output unit switches 10 ₁₁ to 10 ₁₃ in the first row are set to have a characteristic of reflecting an optical signal of wavelength λ ₁ as shown in FIG. 2 (1). Thus, the output b of the 1-input 2-output optical switch 11
The optical signal of wavelength λ ₁ taken out to can be sent to the output line on the output port side.

2-input 2-output unit switch 10 _{21 in} the second row
The optical filters 12 to 10 ₂₃ are, as shown in FIG.
The characteristics are set such that the optical signal of wavelength λ ₁ is transmitted and the optical signal of wavelength λ ₂ is reflected. This allows the optical signal of wavelength λ ₁ input from the input line to be transmitted to the output line,
The optical signal of wavelength λ ₂ extracted at the output b of the 1-input 2-output optical switch 11 can be sent to the output line on the output port side. At this time, the optical signals of wavelengths λ ₁ and λ ₂ are wavelength-multiplexed.

2-input 2-output unit switch 10 _{31 in} the third row
The optical filters 12 to 10 ₃₃ are, as shown in FIG.
The characteristic is set such that an optical signal of wavelength λ ₂ or less is transmitted and an optical signal of wavelength λ ₃ is reflected. Thereby, the optical signals of wavelengths λ ₁ and λ ₂ input from the input line can be transmitted to the output line, and the optical signal of wavelength λ ₃ extracted at the output b of the 1-input 2-output optical switch 11 can be output side. Can be sent to the output line of. At this time, the optical signals of wavelengths λ ₁ , λ ₂ , and λ ₃ are wavelength-multiplexed.

2 input 2 output unit switch 10 _{41 of} the 4th row
The optical filters 12 to 10 ₄₃ are, as shown in FIG.
The characteristic is set such that an optical signal of wavelength λ ₃ or less is transmitted and an optical signal of wavelength λ ₄ is reflected. As a result, optical signals of wavelengths λ ₁ , λ ₂ , and λ ₃ input from the input line can be transmitted to the output line, and the output b of the 1-input 2-output optical switch 11 can be transmitted.
The optical signal of wavelength λ ₄ taken out can be sent to the output line on the output port side. At this time, the wavelengths λ ₁ , λ ₂ , λ ₃ ,
The optical signal of λ ₄ is wavelength-division multiplexed.

Here, a specific switching example will be described. Input from the input port 31 ₁ light signals (lambda
_{The case where 1} ) is output to the output port 32 ₂ will be described. Of the three 2-input 2-output unit switches 10 ₁₁ to 10 ₁₃ arranged in the row direction with respect to the input port 31 ₁ , the 2-input 2-output unit switch 10 corresponding to the output port 32 _2.
Set the 1-input 2-output optical switch 11 of ₁₂ to the output b side,
Others are set on the output a side where the optical signal goes straight. As a result, the optical signal input from the input port 31 ₁ has two-input two-output unit switches 10 ₁₁ , 10 ₁₂ , 10 ₂₂ , 10 ₃₂ ,
It is output to the output port 32 ₂ via 10 ₄₂ . In addition,
There is one route.

The 2-input 2-output unit switch 10 ₁₁ outputs the input optical signal to the output a of the 1-input 2-output optical switch 11.
From the 2 input 2 output unit switch 10 through the output line
Send to ₁₂ . The 2-input 2-output unit switch 10 ₁₂ receives the optical signal input from the input line and outputs the 1-input 2-output optical switch 1
It is output from the output b of 1 and is reflected by the optical filter 12 to be sent to the 2-input 2-output unit switch 10 ₂₂ via the output line.
In the 2-input 2-output unit switch 10 ₂₂ , the optical signal input from the input line is transmitted by the optical filter 12 and is sent to the 2-input 2-output unit switch 10 ₃₂ via the output line.

At this time, the 2-input 2-output unit switch 10
_{At 22} , if there is an optical signal traveling from the input port 31 ₂ to the output port 32 ₃ , the optical signal of the output a of the 1-input 2-output optical switch 11 and the optical signal of the input line intersect, but due to the straightness of light, both The signals are transmitted without interfering with each other.
If there is an optical signal traveling from the input port 31 ₂ to the output port 32 ₂ , the output b of the 1-input 2-output optical switch 11
Optical signal (λ ₂ ) and the optical signal (λ ₁ ) on the input line are input to the optical filter 12, the former is reflected and the latter is transmitted, and wavelength-multiplexed to the next 2-input 2-output unit switch 10 ₃₂ . Sent. In this way, the optical filter 12 has a function of wavelength-multiplexing optical signals going to the same output port. Similarly, the optical signals are input to the two-input two-output unit switches 10 ₃₂ ,
The light passes through the optical filters 12 of ₄₂ and is output to the output port 32 ₂ .

In order to facilitate the description of the optical filter 12, the case where the wavelength of the optical signal input to each input port is fixed has been described above. However, an optical signal input to the input port 31 ₁ to 31 ₄ can be any wavelength as long as different wavelengths. In that case, as the optical filter 12, a filter having a characteristic of reflecting only an optical signal of a specific wavelength is used. An example thereof is shown in FIG.

When an optical signal of wavelength λ ₄ is input to the input port 31 ₁ , as shown in FIG. 3 (1), the optical filter 12 of the 2-input 2-output unit switch at the position corresponding to the output port is used. , Sets the characteristic of reflecting the optical signal of wavelength λ ₄ and transmitting the optical signal of other wavelengths. Thereby, the wavelength λ extracted at the output b of the 1-input 2-output optical switch 11
₄ optical signals can be sent to the output line.

[0031] When inputting the optical signal of the wavelength lambda ₂ to the input port 31 _2, as shown in FIG. 3 (2), likewise the wavelength lambda
_The optical filter 12 is set to have a characteristic of reflecting the optical signal No. ₂ and transmitting the optical signals of other wavelengths. This gives the wavelength λ
The optical signal of ₄ can be transmitted from the input line to the output line, and the optical signal of wavelength λ ₂ extracted at the output b of the 1-input 2-output optical switch 11 can be sent to the output line. When the optical signals of wavelengths λ ₄ and λ ₂ input from the input ports 31 ₁ and 31 _{2 go} to the same output port, both optical signals are wavelength-multiplexed and sent to the output line.

When an optical signal of wavelength λ ₃ is input to the input port 31 ₃ , as shown in FIG.
_The optical filter 12 is set to have a characteristic of reflecting the optical signal ₃ and transmitting the optical signals of other wavelengths. This gives the wavelength λ
The optical signals of ₂ and λ ₄ can be transmitted from the input line to the output line, and the optical signal of wavelength λ ₃ extracted at the output b of the 1-input 2-output optical switch 11 can be sent to the output line. When the optical signals of wavelengths λ ₄ , λ ₂ , λ ₃ input from the input ports 31 ₁ , 31 ₂ , 31 _{3 go} to the same output port, the optical signals are wavelength-multiplexed and sent to the output line. .

When inputting an optical signal of wavelength λ ₁ to the input port 31 ₄ , as shown in FIG.
_The optical filter 12 is set to have a characteristic of reflecting the optical signal of ₁ and transmitting the optical signals of other wavelengths. This gives the wavelength λ
The optical signal of _{2 to} λ ₄ can be transmitted from the input line to the output line, and the optical signal of wavelength λ ₁ extracted at the output b of the 1-input 2-output optical switch 11 can be sent to the output line. When the optical signals of wavelengths λ ₄ , λ ₂ , λ ₃ , λ ₁ input from the input ports 31 ₁ , 31 ₂ , 31 ₃ , 31 _{4 go} to the same output port, the optical signals are wavelength-multiplexed. It is sent to the output line.

As described above, even if the wavelength of the optical signal input to each input port is arbitrarily selected, the optical filter 1 of the 2-input 2-output unit switch where the input port and the output port intersect with each other.
By setting the corresponding reflection wavelength and the transmission wavelengths on both sides with respect to No. 2, it is possible to realize wavelength multiplexing processing of optical signals going to the same output port.

By the way, the 2-input 2-output unit switch 10
Then, crosstalk occurs only in the 1-input / 2-output optical switch 11, and appears only on the non-switching side. Further, the crosstalk generated on the output b side of the 1-input 2-output optical switch 11 of each 2-input 2-output unit switch 10 is added by the optical filter 12 and taken out to the output port, and the 2-input 2-output arranged in the row direction. It does not depend on the number of unit switches. Therefore, the maximum value of the crosstalk that appears at each output port is the added value of the crosstalk in the 2-input 2-output unit switch arranged in the column direction. If the crosstalk level of the 1-input 2-output optical switch is set to -20 dB as in the conventional example, the deterioration becomes 9 dB (SN ratio 11 dB) at the maximum in the 8x8 matrix switch. Thus, the optical matrix switch of the present invention can significantly reduce crosstalk.

FIG. 4 shows the configuration of the second embodiment of the present invention. In this embodiment, wavelength-multiplexed wavelengths λ _{1 to} λ ₄
2 is an example of a configuration for distributing the optical signal of 1 to each of the three output ports in an arbitrary combination. Both the number of wavelength division multiplexing and the number of output ports can correspond to arbitrary numbers.

In the figure, the WDM signal input port 13
The wavelength-multiplexed optical signals of wavelengths λ _{1 to} λ ₄ are input to the. This wavelength-multiplexed optical signal is demultiplexed by the optical signal demultiplexer 14 for each wavelength and input to the _four input ports 31 _{1 to} 31 ₄ of the optical matrix switch. 4 input ports 3
The coupling relationships of 1 _{1 to} 31 ₄ , 3 output ports 32 _{1 to} 32 ₃ , 1 input and 2 output unit switches 10 ₁₁ to 10 ₄₃ are the same as in the first embodiment. However, in the 2-input 2-output unit switches 10 ₁₁ to 10 ₁₃ in the first row, there is no other optical signal that is wavelength-multiplexed and goes to the same output port.
By omitting 2, the output b of the 2-input 2-output unit switch 11 and the output line are directly connected.

In the configuration of this embodiment, each input port 31 ₁
Since the optical signals of wavelengths λ ₁ to λ ₄ are input to ˜31 ₄ in that order, the optical filter 12 having the characteristics shown in FIG. 2 is mounted on the 2-input 2-output unit switch 10 for each row. The function of the optical matrix switch is the same as the first embodiment, can be distributed in any combination of each optical signal of the wavelength lambda ₁ to [lambda] _4, which is wavelength-multiplexed to each output port. That is, each optical signal can be wavelength-multiplexed and transmitted to the same output port in any combination.

[0039]

As described above, in the M-input / N-output optical matrix switch according to the present invention, the optical signals of different wavelengths input from the respective input ports are output to the respective output ports at any wavelength including wavelength multiplexing. You can sort by combination. Moreover, since M × N 1-input / 2-output optical switches can be arranged in a matrix, it is possible to realize miniaturization and low power consumption.

By using the 1-input 2-output optical switch, it is possible to realize an optical matrix switch in which the accumulation of crosstalk is small. Therefore, the SN ratio of the optical signal is improved, and it is possible to handle a high-speed optical signal. Further, it is possible to easily expand the scale of the optical matrix switch. In particular, since the accumulation of crosstalk does not depend on the number of 2-input 2-output unit switches arranged in the row direction, it is effective in constructing an optical matrix switch having a large size in the row direction.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the wavelength of an input port and the characteristics of an optical filter 12.

FIG. 3 is a diagram showing the relationship between the wavelength of an input port and the characteristics of the optical filter 12.

FIG. 4 is a block diagram showing the configuration of a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration example of a conventional optical matrix switch.

FIG. 6 is a diagram showing a configuration example of a 2-input 2-output optical switch 40.

[Explanation of symbols]

 10 2 Input 2 Output Unit Switch 11 1 Input 2 Output Optical Switch 12 Optical Filter 13 Wavelength Multiplexed Signal Input Port 14 Optical Signal Demultiplexer 31 Input Port 32 Output Port 40 2 Input 2 Output Optical Switch 41 Input Waveguide 42 Output Waveguide 43 3dB coupler 44 Thermo-optical phase shifter

Claims (1)

[Claims] 1. An optical matrix switch having a plurality of M input ports and a plurality of N output ports, which outputs an optical signal input from an arbitrary input port to an arbitrary output port, to which an optical signal is input. First and second input lines, a 1-input 2-output optical switch connected to the first input line, a first output line connected to one output of the 1-input 2-output optical switch, and 1 An optical filter that joins the optical signal of the other output of the input / output 2 optical switch and the optical signal of the second input line, and a second output line connected to the output of the optical filter are 2 inputs and 2 outputs of 1 unit. A unit switch, wherein the 2-input 2-output unit switches are arranged in M rows and N columns, and the first 2-input 2-output unit switches in each column are arranged in a matrix.
Connected to the second input line and the second input line of the 2-input 2-output unit switch of each row, and connecting the second output line and the second input line of the 2-input 2-output unit switch of each row, 1 input line is connected to each of the M input ports,
The above-mentioned N is connected to the second output line of the two 2-input 2-output unit switches.
An optical matrix switch having M input and N output switch configurations by connecting a plurality of output ports.