JPH0744712B2 - Optical signal disconnection detection method for matrix optical switch - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to maintenance in optical switching,
In particular, the present invention relates to a method of detecting disconnection between an optical fiber connected to an optical switch and an optical waveguide of the optical switch itself and a switching failure of the optical switch.

[0002]

2. Description of the Related Art FIG. 7 is an explanatory view of an optical signal disconnection detection method of a conventional matrix optical switch, where 1 is an N.times.M matrix optical switch and 2 is an 2.times.2 light which constitutes an N.times.M matrix optical switch. A switch 3, an optical coupler, 4 an opto-electric converter, 5 an optical fiber, 6 an optical waveguide in the N × M matrix optical switch 1, and 7 an N × M matrix optical switch to which input light P1 to PN is input. 1 input end, 8 output light Q
1 to QM is an output end of the N × M matrix optical switch 1.

Here, the 2 × 2 optical switch 2 is, for example,
"Technical Report of IEICE, OQE90-15
4, P.P. 37-P. 42 ”(Reference A), an electronic optical switch that switches the optical path by changing the refractive index of the waveguide by an electric field. Further, the optical coupler 3 is described, for example, in “Introduction to Optical Fiber Communication” by Suematsu and Iga, P.13.
9-P. 140, published by Ohmsha Co., Ltd. "(Document B).

Then, an optical coupler 3 is connected to the optical fibers 5 at the input / output terminals 7 and 8, and a signal branched by the optical coupler 3 is converted into an electric signal by an optoelectric converter 4 and is monitored, whereby The presence or absence of light was confirmed, and light blocking was detected.

[0005]

However, in the above-mentioned conventional optical signal disconnection detection method for the matrix optical switch, since the branching optical coupler and the monitoring photoelectric converter must be provided for each input / output, the optical maintenance is required. A dedicated N + M optical couplers and N + M optical-electrical converters are required, and there is a problem that the optical circuit for optical maintenance and the amount of hardware of the optical-electrical circuit are large.

The present invention solves the above problems and provides an optical signal disconnection detection method for a matrix optical switch having a simple hardware configuration in which an optical coupler is eliminated and a single monitor photoelectric converter is provided. The purpose is to

[0007]

In order to solve the above problems, the present invention provides a method for detecting an optical signal disconnection of a matrix optical switch, wherein a first and a second input terminal and a first and a second input terminal are provided.
2 × 2 optical switches that have an output terminal of, and can take a cross state, a bar state, and an intermediate state thereof are arranged in a matrix of N rows and M columns, and the input terminals of each row arranged in this matrix shape and 1 row 1 connected to the output terminal of each column
N + 1 row M + 1 by adding 2 × 2 optical switch for column monitoring
2x2 each arranged in a column matrix and arranged in the first row
The first input terminal of the optical switch, the first of the 2 × 2 optical switches arranged in the 1st row, (M + 1) th column to the Nth row, (M + 1) th column
Output terminals and the 2 × arranged in the (N + 1) th row and 1st column
The second input terminal and the second output terminal of the two-optical switch are opened, and the second output terminals of each 2 × 2 optical switch are arranged in the i-th row and the second output terminals of each 2 × arranged in the i + 1-th row. The first output terminal of each 2 × 2 optical switch connected to the first input terminal of the two-optical switch and arranged in the j-th column is the j + 1-th
Connected to the second input terminal of each 2 × 2 optical switch arranged in a row (where i = 1 to N−1, j = 1 to M−1),
The 1st to Nth inputs P1 to PN are input to the second input terminals of the 2 × 2 optical switches in the 1st row, 1st column to the Nth row, 1st column, and the N + 1th row, 2nd column to N + 1th row M
The second output terminal of the 2 × 2 optical switch on the + 1th column is connected to the M-th
A first output QM to Q1 are connected, and a photoelectric converter is connected to the first output terminal of the 2 × 2 optical switch on the (N + 1) th row and the (M + 1) th column, and the i-th input Pi is disconnected. When the test is performed, the 2 × 2 optical switch in the 1st row and the i-th column is set to an intermediate state between the cross state and the bar state, and when the disconnection test of the jth output Qj is performed, the N + 1th row, M + 2-j The 2 × 2 optical switches in the row are set to an intermediate state between the cross state and the bar state (where i = 1 to N and j = 2 to M + 1).

In the present invention, the bar state means 2
In a × 2 optical switch, the first input is straightly connected to the first output, the second input is straightly connected to the second output, and the cross state is 2 × 2.
In the optical switch, the first input is straightly connected to the second output, the second input is straightly connected to the first output, and the intermediate state between the cross state and the bar state is In a 2 × 2 optical switch, a first input is connected straight to a first output and crossed to a second output, and a second input is straightened to a second output and crossed to a first output. It means the state of being connected to.

[0009]

According to the present invention, the optical signal disconnection detecting method for the matrix optical switch is configured as described above.
When testing the disconnection of the first input P1,
The 2 × 2 optical switches in the row are set to an intermediate state between the cross state and the bar state. At this time, the input P1 is divided into two outputs by the 2 × 2 optical switch, one optical output of which is one row and two columns,
From 1st row and 3rd column ... 1st row and M + 1th column to 2nd row, M + 1th column, 3rd row, M + 1th column, ... N + 1th row and M + 1th column, and output Q1, while the other is 2nd row and 1st column, 3rd row and 1st column It is input to the photoelectric converter and monitored through N + 1 row 1 column to N + 1 row 2 column ... N + 1 row M + 1 column.

Further, when the disconnection test of the first output Q1 is performed, the 2 × 2 optical switch in the (N + 1) th row and the (M + 1) th column is set to an intermediate state between the cross state and the bar state. At this time, the light input to the 2 × 2 optical switch is split into two, one of which becomes the output Q1 and the other is input to the photoelectric converter and monitored.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of an optical signal disconnection detecting method for a matrix optical switch according to a first embodiment of the present invention.
The description will be omitted because it is redundant.

In the figure, 9 is (N + 1) × (M + 1)
It is a matrix optical switch and is in a cross state or a bar state depending on the applied voltage, that is, in the 2 × 2 optical switch 2,
The first input is connected straight to the first output and the second
Input is directly connected to the second output, and an intermediate state, that is, in the 2 × 2 optical switch 2, the first input is straight to the first output and the second output is crossed. Connected to the second input straight to the second
2 × 2 optical switch 2 capable of being connected to the first output and the output of the (N + 1) row (M +
1) It is configured by connecting multiple stages in a column matrix.

The input P1 is connected to the input I1 of the first row, the input P2 is connected to the input I2 of the second row, and so on. Similarly, the input PN is connected to the input IN of the Nth row.
The input IN + 1 of the first row is open. And (N
The output Q1 is connected to the output O1 of the first column of the (+1) × (M + 1) matrix optical switch 9, and the output QM is connected to the output OM of the Mth column in the same manner, and the output QM + 1 of the M + 1th column is It will be open. Further, the input of the opto-electric converter 4 is connected to the other output of the 2 × 2 optical switch 2 connected to the output Q1.

Further, in FIG. 1, as will be described later with reference to FIGS. 2 and 3, i1 indicates a first input, i2 indicates a second input, o1 indicates a first output, and o2 indicates a second output. ing. FIG. 2 is a state diagram of a 2 × 2 optical switch forming an (N + 1) × (M + 1) matrix optical switch.
Is in the cross state, and the first input i1 is the second output o2
And the second input i2 is connected to the first output o1. Then, 14 is a bar state, in which the first input i1 is connected to the first output o1 and the second input i2 is connected to the second output o2.

FIG. 3 is a diagram showing a 2 × 2 matrix optical switch constructed by connecting the 2 × 2 optical switches in multiple stages. As shown, the input I1 is connected to the second input 18 of the 1 × 1 2 × 2 optical switch 16 and the input I2 is the second input 27 of the 2 × 1 2 × 2 optical switch 28. Connected to. The first input 15 of the 2 × 2 optical switch 16 is open, and the first output 17 is the 2 × 2 optical switch 21 in the first row and the second column.
Connected to the second input 23 of the second output 19 of 2 × 2
It is connected to the first input 25 of the optical switch 28. 2x2
The first input 20 and the first output 22 of the optical switch 21 are opened, and the second output 24 is connected to the first input 33 of the 2 × 2 optical switch 31 of 2 rows and 2 columns. The first output 26 of the 2x2 optical switch 28 is connected to the second input 30 of the 2x2 optical switch 31 and the second output 29 is connected to the output O2. The first output 34 of the 2 × 2 optical switch 31 is open and the second output 32 is connected to the output O1.

Similarly to this, a 2 × 2 optical switch is connected to N +
The (N + 1) × (M + 1) matrix optical switch shown in FIG. 1 can be configured by connecting one row and M + 1 columns in multiple stages. Note that, here, even if the connection of the first and second input terminals of the 2 × 2 optical switch 2 is reversed, the states of the cross state and the bar state are only reversed, and therefore the applied voltage described below is reversed. By doing so, the same switching operation can be performed. Similarly, the connection of the first and second output terminals may be reversed.

Further, in correspondence with FIG. 2, as shown in the 2 × 2 optical switch 16, the first input i1, the second input i2, the first output o1 and the second output o2 are obtained. .
FIG. 4 is a diagram showing the relationship between the applied voltage and the output power of the 2 × 2 optical switch, which is disclosed in Document A. As is clear from the figure, the light input to i1 is in a cross state at 9.0V, and light is output to o2 and no light is output to o1. Further, at 21.5 V, the bar state is set, light is output to o1, and light is not output to o2. In the states other than the cross state and the bar state, light is distributed to o1 and o2 according to the applied voltage and output. For example, applied voltage 15V
The optical output is divided into o1 and o2 and output.

FIG. 5 is a circuit diagram showing an example of a 2 × 2 optical switch drive circuit. When S1 and S2 are High, a cross state is set, one of S1 and S2 is High and the other is Lo.
The state of w is an intermediate state between the cross state and the bar state. Next, a method of monitoring the input light and the output light in the first embodiment will be described with reference to FIG. Where P
, P2, PN and Q1, ..., QM have a one-to-one correspondence with N = M.

First, in the above connection state, (N + 1)
× (M + 1) 2 × 2 constituting the matrix optical switch 9
The optical switch 2 includes 1 row M + 1 column, 2 rows M columns ... N rows 2
Column and N + 1 row and 1 column are in bar state, and other 2 ×
2 If the optical switch 2 is in the cross state, P1 →
Q1, P2 → Q2, PN → QM are connected, and the input / output is not monitored.

Next, when it is desired to monitor the input P1, the 1 × 1 2 × 2 optical switch 2 is set to the intermediate state between the cross state and the bar state from the above-mentioned connected state. At this time, the input P1 is divided into two outputs by the 2 × 2 optical switch 2, one optical output of which is 1 row 2 columns, 1 row 3 columns ... 1 row N + 1 column to 2 rows N + 1 column, 3 rows. N + 1 column ... M + 1 row and N + 1 column to output Q1 and the other is 2 row 1 column, 3 row 1 column ... N + 1 row 1 column to N + 1 row 2 column ... N + 1 row M
It is input to the photoelectric converter 4 through the +1 column.

Similarly, the inputs P2 to PN are brought into the monitor state by setting the 2 × 2 optical switch 2 of the 2nd row and 1st column to the Nth row and 1st column to the intermediate state between the cross state and the bar state. Also,
Similarly, the outputs Q1 to QM are brought into a monitor state by setting the 2 × 2 optical switch 2 of N + 1 row, M + 1 column to N + 1 row, 2 column to an intermediate state between the cross state and the bar state. In this way, by sequentially monitoring each of P1 to PN and Q1 to QM, it is possible to monitor all the optical input / output.

The actual operation of the monitor will be described in detail below. (1) In the first input P1, disconnection means a decrease in output of the light emitting source, disconnection of the optical fiber, and light is coupled from the optical fiber to the 2 × 2 optical switch in the (N + 1) × (M + 1) matrix optical switch. 2x from the input side such as disconnection until
It means that light is not input to the two-optical switch.

The disconnection test is a test for confirming whether or not these input lights are input to the optical switch. (2) The disconnection test of the jth output Qj will be described by taking the M + 1th output QM + 1 as an example. Light from a light emitting source passes through the optical switch in the 1st row and the 1st column, and the optical switch in the 1st row (M + 1) th column. Suppose that the route is set to the route through which the optical switch of the (N + 1) th row and the (M + 1) th row is output, and here, the disconnection means the output reduction of the light emitting source, the disconnection of the optical fiber, the optical fiber. -1 row 1 column -1 row (M + 1)-
It means that the optical output is not input in the route up to the point B due to disconnection in the route before the (N + 1) th row and (M + 1) th column, malfunction of the optical switch / driving circuit, and the like.

The disconnection test is a test for confirming whether the input light is in a state of being output from the optical switch. With this configuration, the optical switch can be set to an intermediate state between the cross state and the bar state according to the mode of the monitor without adding any hardware for the monitor, so that the optical signal can be easily transmitted in the optical transmission state. It is possible to detect disconnection.

FIG. 6 is an explanatory diagram of an optical signal disconnection detection method for a matrix optical switch according to the second embodiment of the present invention.
2 + 1 optical switch 2 of N + 1 row and 1 column in the first embodiment
Is always used in the bar state, the input / output of the 2 × 2 optical switch 2 is short-circuited, and a modified (N + 1) × (M + 1) matrix optical switch 1 in which one 2 × 2 optical switch 2 is omitted is used.
0 is provided, and other than that is the same as the first embodiment.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention, and these modifications are not excluded from the scope of the present invention.

[0027]

As described above in detail, according to the present invention, the detection of the disconnection of the optical input / output branches the light in the intermediate state between the cross state and the bar state of the input / output 2 × 2 optical switch, Since the optical switch is sequentially controlled according to the mode of the monitor and the line is monitored, the maintenance of the conventional N × M optical switch requires N + M optical couplers and N + M photoelectric converters. Since it can be realized by additionally integrating the 1-row 1-column optical switch on the input / output side and using one photoelectric converter, the hardware can be reduced.

Further, without adding any hardware for the monitor, the optical switch is set to an intermediate state between the cross state and the bar state according to the mode of the monitor, so that the optical signal disconnection can be easily detected in the optical transmission state. It can be carried out.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an optical signal disconnection detection method for a matrix optical switch according to a first embodiment of the present invention.

FIG. 2 is a state diagram of a 2 × 2 optical switch.

FIG. 3 is a diagram in which 2 × 2 optical switches are connected in multiple stages to form a 2 × 2 matrix optical switch.

FIG. 4 is a diagram showing a relationship between an applied voltage and an output power of a 2 × 2 optical switch.

FIG. 5 is a circuit diagram showing an example of a 2 × 2 optical switch drive circuit.

FIG. 6 is an explanatory diagram of an optical signal disconnection detection method for a matrix optical switch according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a conventional optical signal disconnection detection method for a matrix optical switch.

[Explanation of symbols]

1 N × M Matrix Optical Switch 2 2 × 2 Optical Switch 3 Optical Coupler 4 Photoelectric Converter 5 Optical Fiber 6 Optical Waveguide 7 Input End 8 Output End 9 (N + 1) × (M + 1) Matrix Optical Switch 10 Modification (N + 1) × (M + 1) matrix optical switch

Claims (3)

[Claims] 1. A 2 × 2 optical switch having (a) first and second input terminals and first and second output terminals and capable of taking a cross state, a bar state and an intermediate state thereof. N row M
Arranged in a column matrix, (b) input terminals of each row arranged in the matrix, and
1x1 2x2 light for monitoring connected to the output terminal of each column
Add switches and arrange them in a matrix of N + 1 rows and M + 1 columns.
(C) the first input terminal of each 2 × 2 optical switch arranged in the first row, the 2 × 2 optical switch arranged in the 1st row , ( M + 1) th column to the Nth row, (M + 1) th column. First output terminal and Nth
The second of the 2 × 2 optical switches arranged in +1 row and 1 column
The input terminal and the second output terminal are opened, and (d) the second output terminal of each 2 × 2 optical switch arranged in the i-th row is a 2 × 2 optical switch arranged in the i + 1-th row. Connected to the first input terminal of each of the 2 × 2 optical switches arranged in the j-th column and the first output terminal of each 2 × 2 optical switch arranged in the j + 1-th row is the second input of each of the 2 × 2 optical switches. Connected to terminals (where i = 1 to N-1, j = 1 to M-1), and (e) second row of the 2 × 2 optical switch from the first row, first column to the Nth row, first column. The first to Nth inputs P1 to P to the input terminals of
Input N and at the (N + 1) th row and the 2nd column to the (N + 1) th
The Mth to first outputs QM to Q1 are connected to the second output terminal of the 2 × 2 optical switch in the row M + 1th column, and the Nth +
A photoelectric converter is connected to the first output terminal of the 2 × 2 optical switch on the 1st row and the M + 1th column, and (f) when the disconnection test of the i-th input Pi is performed, When the 2 × 2 optical switch is set to an intermediate state between the cross state and the bar state and the disconnection test of the j-th output Qj is performed, the 2 × 2 optical switch in the (N + 1) th row and the (M + 2-j) th column is set to the cross state. A machine characterized in that it is in an intermediate state of the bar state (where i = 1 to N, j = 2 to M + 1) .
Optical signal disconnection detection method for Trix optical switch . 2. The second output terminal of the 2 × 2 optical switch arranged in the Nth row and the 1st column and the second input terminal of the 2 × 2 optical switch arranged in the (N + 1) th row and the 2nd column are connected. And then N + 1
2. The optical signal disconnection detection method for a matrix optical switch according to claim 1, wherein the 2 × 2 optical switches arranged in the first row and the second row are omitted. 3. A 2 × 2 Sequential controls the optical switch in an intermediate state of the cross state and the bar state claim 1 or 2
A method for detecting an optical signal disconnection of the described matrix optical switch .