JPH05122745A - Optical signal disconnection detecting method - Google Patents

Abstract

(57) [Abstract] [Purpose] One M / N optical switch disconnection is detected by one opto-electric converter for monitoring. [Structure] When the disconnection test of the first input P1 is performed, the 2 × 2 optical switch 2 in the first row and first column is set to an intermediate state between the cross state and the bar state. Input P1 is 2 × 2 optical switch 2
Are divided into 2 outputs, one of which is 1 row 2 columns, 1 row 3 columns.
.... 1 row M + 1 column, 2 rows M + 1 column, 3 rows M + 1 column ...
The output Q1 passes through N + 1 row M + 1 column, and the other passes through 2 row 1 column, 3 row 1 column ... N + 1 row 1 column, N + 1 row 2 column ... N + 1 row M + 1 column, and photoelectric converter 4 Input to and monitored. Similarly, 2 rows and 1 column to 2 rows of N rows and 1 column
When the × 2 optical switch is set to the intermediate state between the cross and the bar, the inputs P2 to PN are monitored, and N + 1 rows and M + 1 columns to N + 1.
The outputs Q1 to QM are monitored when the 2 × 2 optical switch 2 in the row 2 column is set to an intermediate state between the cross state and the bar state.

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 for 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. 8 is an explanatory view of a conventional optical signal disconnection detecting method, wherein 1 is an N × M optical matrix switch and 2 is an N × M optical matrix switch.
2 × 2 optical switch that constitutes M optical matrix switch,
3 is an optical coupler, 4 is a photoelectric converter, 5 is an optical fiber, 6
Is an optical waveguide in the N × M optical matrix switch, 7 is an input end of the N × M optical matrix switch 1 to which input lights I1 to IN are input, and 8 is N × M to output output lights O1 to OM
The output terminal of the optical matrix 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.
9-P. 140, published by Ohmsha Co., Ltd. (Reference B). The optical branching / directional coupler and the optical tap are used.

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 opto-electric converter 4 and is monitored. 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, since a branching optical coupler and a monitor photoelectric converter must be provided for each input / output, there are N + M dedicated optical maintenances. An optical coupler and N + M photoelectric converters are required, and there is a problem that the amount of hardware of the optical circuit and the photoelectric circuit for optical maintenance is large.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide an optical signal disconnection detecting method in which an optical coupler is deleted and one monitor photoelectric converter is provided.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for detecting an optical signal disconnection, which comprises:
2 × 2 optical switches having a second input terminal and first and second output terminals and capable of taking a cross state, a bar state and an intermediate state thereof are arranged in a matrix of N + 1 rows and M + 1 columns, The first of each 2x2 optical switch arranged in one row
Input terminals, first output terminals of the 2 × 2 optical switches arranged in the 1st row, (M + 1) th column to the Nth row, (M + 1) th column, and the 2 × 2 optical switches arranged in (N + 1) th row, 1st column Second
Of the 2 × 2 optical switches arranged in the i-th row and the first output terminal of the 2 × 2 optical switches arranged in the (i + 1) th row. Of the 2 × 2 optical switches arranged in the j-th column and connected to the input terminals of the 2 × 2 optical switches, and the first output terminals of the 2 × 2 optical switches are arranged in the j + 1-th row.
Connect to the second input terminal of the × 2 optical switch (provided that i
= 1 to N-1, j = 1 to M-1), and the first input to the second input terminal of the 2 × 2 optical switch in the first row, first column to the Nth row, first column.
From the Nth input P1 to PN,
The Mth to first outputs QM to Q1 are connected to the second output terminals of the 2 × 2 optical switch from the 1st row and the 2nd column to the N + 1th row and the M + 1th column, and the 2nd row from the N + 1th row and the M + 1th column 2 × When a photoelectric converter is connected to the first output terminal of the two-optical switch and a disconnection test of the i-th input Pi is to be performed, the above-mentioned 2 ×
When the two-optical switch is set to an intermediate state between the cross state and the bar state and the disconnection test of the jth output Qj is performed, the (N + 1) th output is performed.
The 2 × 2 optical switch in the row M + 2-jth column is set to an intermediate state between the cross state and the bar state (where i = 1 to N,
j = 2 to M + 1).

[0008]

According to the present invention, since the optical signal disconnection detecting method is configured as described above, for example, when the disconnection test of the first input P1 is performed, the 2 × 2 optical switch in the first row and the first column is used. To a 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 1 row 2 columns, 1 row 3 columns ... 1 row M + 1.
From column 2 rows M + 1 columns, 3 rows M + 1 columns ... N + 1 rows M +
It goes through one column and becomes output Q1, and the other is 2 rows and 1 column, 3
Row 1 column ... N + 1 row 1 column to N + 1 row 2 column ... N +
It is input to the photoelectric converter through 1 row and M + 1 column and monitored.

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.

[0010]

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 according to a first embodiment of the present invention, in which the same technical means as in the conventional art are denoted by the same reference numerals. In the figure, 9 is a (N + 1) row (M +) 2 × 2 optical switch 2 capable of taking a cross state, a bar state and an intermediate state depending on an applied voltage.
1) Multi-stage connection in a row matrix form (N + 1)
In the × (M + 1) optical matrix switch, the input P1 is connected to the first input I1, the input P2 is connected to the second input I2, and so on, and the input PN is connected to the Nth input IN. , The (N + 1) th input IN + 1 is open. Then, the output Q1 is connected to the first output O1 of the (N + 1) × (M + 1) optical matrix switch 9, the output QM is connected to the Mth output OM in the same manner, and the M + 1th output QM + 1 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.

FIG. 2 is a state diagram of a 2 × 2 optical switch forming an (N + 1) × (M + 1) optical matrix switch.
3 is in the cross state, and the first input i1 is the second output o
2, the second input i2 is connected to the first output o1.
14 is a bar state, and the first input i1 is the first
Output o1 of the second input i2 is connected to the second output o2.

FIG. 3 is a diagram showing a 2 × 2 optical matrix 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 opened, and the first output 17 is the 2 × 2 optical switch 21 of 1 row and 2 columns.
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, by connecting 2 × 2 optical switches in N + 1 rows and M + 1 columns in multiple stages, (N + 1) × (M +
1) An optical matrix switch can be constructed. 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, so the applied voltage described later is reversed. Therefore, the same switching operation can be performed. Similarly, the first
The connection of the second output terminal may be reversed.

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 above. As is clear from the figure, the light input to i1 is in a cross state at 9.0 V, and the light is output to o2.
No light is output to. Further, at 21.5 V, the bar state is set, light is output to o1, and light is not output to o2.
In states other than the cross state and the bar state, light is distributed to o1 and o2 according to the applied voltage and is output. For example, with an applied voltage of 15 V, 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 driving circuit. When S1 and S2 are High, a crossing state occurs, and one of S1 and S2 is High and the other is Lo.
When w, the state is 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
It is assumed that N = M so that 1, P2, PN and Q1, Q2, QM have a one-to-one correspondence.

First, in the above connection state, (N + 1)
× (M + 1) 2 × 2 constituting the optical matrix switch 9
The optical switch 2 has 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 → QN are connected, and the input / output is not monitored.

Next, when it is desired to monitor the input P1, the 2 × 2 optical switch 2 in the 1st row and the 1st column is set to the intermediate state between the cross state and the bar state from the above connection 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 columns to 2 rows N columns, 3 rows. Nth column: M + 1 row, N + 1th column, output Q
1 and the other is 2 rows and 1 column, 3 rows and 1 column ... N + 1
It is input to the photoelectric converter 4 from the row 1 column through the N + 1 row 2 column ... N + 1 row M + 1 column.

Inputs P2 to PN are similarly 2 rows 1 column to N rows 1
By setting the 2 × 2 optical switches 2 in the row to an intermediate state between the cross state and the bar state, the monitor state is set. Similarly, the outputs Q1 to QM also enter the monitor state by setting the 2 × 2 optical switches 2 in the N + 1th row, the M + 1th column to the N + 1th row, the 2nd column, between the cross state and the bar state. in this way,
By monitoring the states of P1 to PN and Q1 to QM in a time-sharing manner, it is possible to monitor all of the light input and output.

FIG. 6 is an explanatory view of an optical signal disconnection detecting method according to the second embodiment of the present invention. Since the N + 1 row and 1 column 2 × 2 optical switch in the first embodiment is always used in the bar state, The input and output of the 2 × 2 optical switch 2 are short-circuited, and 2 × 2
Modification (N + 1) × (M +) with one optical switch 2 omitted
1) The optical matrix switch 10 is provided, and the other points are the same as in the first embodiment.

FIG. 7 is a diagram showing a third embodiment, which is an example in which an optical disconnection detection optical circuit network 12 composed of one column and N + 1 rows of the second embodiment and an N × M optical switch 11 are combined. The N × M optical switch 11 can use any optical switch as long as the input is N and the output is M. In addition,
The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0020]

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 line monitoring is performed by time division, the maintenance of the conventional N × M optical switch requires N + M optical couplers and N + M optical / electrical converters, whereas the input / output side has one row and one column. Since it can be realized by additionally integrating the optical switch and using one opto-electric converter, the hardware can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an optical signal disconnection detection method 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 optical matrix 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 an optical switch drive circuit.

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

FIG. 7 is an explanatory diagram of an optical signal disconnection detection method according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a conventional optical signal disconnection detection method.

[Explanation of symbols]

1 N × M Optical Matrix 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) Optical Matrix Switch 10 Modification (N + 1) × (M + 1) optical matrix switch 11 N × M optical switch

Claims (4)

[Claims] 1. (a) First and second input terminals and first and second input terminals
N + is a 2 × 2 optical switch that has a second output terminal and can take a cross state, a bar state, and an intermediate state.
Arranged in a matrix of 1 row and M + 1 columns, and (b) arranged from the 1st input terminal of each 2 × 2 optical switch arranged in the 1st row, from the 1st row of the M + 1th column to the Nth row of the M + 1th column. First output terminal and Nth output terminal of each 2 × 2 optical switch
The second of the 2 × 2 optical switches arranged in +1 row and 1 column
(2) each of the 2 × 2 optical switches arranged in the i-th row has the second output terminal of each 2 × 2 optical switch arranged in the i-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 (d) 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 from the 2nd column to the (N + 1) th
The Mth to first outputs QM to Q1 are connected to the second output terminals of the 2 × 2 optical switches 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 (e) 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 at the (N + 1) th row and the (M + 2-j) th column is set to the cross state. An optical signal disconnection detection method, characterized in that an intermediate state of the bar state (where i = 1 to N, j = 2 to M + 1) is set. 2. A second output terminal of the 2 × 2 optical switch arranged at the Nth row and the 1st column and a second input terminal of the 2 × 2 optical switch arranged at the (N + 1) th row and the 2nd column are connected. And then N + 1
2. The optical signal disconnection detection method according to claim 1, wherein the 2 × 2 optical switch arranged in the first row and the second column is omitted. 3. The optical signal disconnection detection method according to claim 1, wherein the 2 × 2 optical switch is controlled in an intermediate state between a cross state and a bar state by time division. 4. The i-th row and j-th column (where i = 1 to N, j
The optical signal disconnection detection method according to claim 1 or 2, wherein a 2x2 optical switch having N input terminals and M output terminals is provided in place of the optical matrix switches arranged in (2 to M + 1).