JPH1141636A - Crosstalk shut-down device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a crosstalk produced from an optical switch. SOLUTION: This device is provided with a monitor means, a control means, and a shut-down means. Monitor means 12, 14, 16, 18 are provided respectively at input ports 11, 12, 13, 14 of an optical switch 100 to detect a strength of a light received by the input ports. The control means 28 controls the shut-down means in response to the signal received from the monitor means and the changeover of the optical switch. The shut-down means 20, 22, 24, 26 allows a light to pass or be cut-off depending on a signal received from the control means 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch having a plurality of input / output ports, and more particularly to a crosstalk shut-down device for suppressing crosstalk output to an output port other than a port to which an optical signal is output.

[0002]

2. Description of the Related Art In recent years, in the field of information communication, with the diversification of communication needs, advancement of information exchange technology and transmission technology, and development of device technology, user information can be exchanged and transmitted at high speed and wide band. Practical application of a high-speed broadband service integrated digital network is rapidly progressing. In this high-speed broadband service integrated digital network, it has been studied to perform switching between devices, for example, system switching between devices and a cross-connect function using optical switches as optical signals. The optical switch method eliminates the need for a function of converting an optical signal into an electric signal and a function of converting an electric signal into an optical signal as compared with the method using an electronic switch, thus increasing the line speed and simplifying the device configuration. ,
Effects such as reduction in the amount of hardware and independence of the transmission speed and transmission method can be expected.

[0003] As one of the optical switches, for example, a document "IEICE OQE 93-34, June 1993"
An 8 × 8 matrix optical switch as disclosed in “Month” has been proposed. This 8 × 8 matrix optical switch is such that a glass waveguide is wired in a lattice pattern on a substrate, and an asymmetric Mach-Zehnder interferometer type switch unit is provided at each part (cross point) where the glass waveguide intersects. It is.

[0004]

However, the above-mentioned matrix optical switch has a problem that crosstalk occurs and the crosstalk adversely affects signal transmission.

In the above document, the crosstalk is described as “the light power of the corresponding output port when light is input to one input port and the corresponding one cross point is turned on (open), and Turn off the cross point (cut off)
This is the difference from the optical power of the corresponding output port when it is caused to occur ”(p. 35).

For example, FIG. 9 is a diagram showing a configuration of a 4 × 4 matrix optical switch. The 4 × 4 matrix optical switch 100 shown in FIG. 9 has four input ports I1, I2, I
3 and I4 and four output ports O1, O2, O3 and O4. FIG. 9 shows a state where the signal light S input to the input port I1 is output to the output port O1. Then, the optical switch 1 is set so that the signal light S is output to the output port O1 in this manner.
Even with the setting of 00, some light leaks not only to the output port O1 but also to the output ports O2, O3 and O4 (arrows C1, C2 and C3 in FIG. 9). The light output leaking to a port other than the target port is called crosstalk.

[0007] The cause of the crosstalk is caused by variations in the waveguide width and the effective refractive index of the waveguide between the directional couplers constituting the switch unit inside the optical switch. If the waveguide width and the like vary, the optical path difference of the Mach-Zehnder interferometer will vary, so the O
N and OFF are not completely performed. Thus, crosstalk occurs.

When the output of the optical switch is ON, if the ratio between the signal intensity and the crosstalk intensity is sufficient, the influence of the crosstalk on the subsequent stage of the optical switch can be ignored. However, when the output of the optical switch is OFF, the output becomes only the crosstalk, so that the influence on the subsequent stage of the optical switch becomes serious. For example, if an optical signal regenerator, such as an optical amplifier, is installed after the optical switch, the crosstalk is amplified, and the light is received even when there is no signal light output from the corresponding output port. Section receives the crosstalk as signal light.

Also, if the intensity of the optical signal input to the input port of the optical switch has a large variation, the S / S at the light receiving section will be high.
There is a problem that the N ratio cannot be sufficiently obtained.

[0010] In the above-mentioned document, a small heater current is supplied even in the cross state (heater OFF state) to correct the deviation from the set value of the optical path length difference. Absorb the error. However, according to the configuration example disclosed in this document, the optimal heater current value for minimizing the error when the heater is turned off differs for each switch unit. Therefore, when the size of the matrix optical switch is large, the optimization adjustment becomes complicated. There is a problem that it becomes. Therefore, creating the configuration disclosed in the literature requires a great deal of time and effort, and is not efficient.

Therefore, there has been a demand for a device that efficiently suppresses the influence of crosstalk.

[0012]

Therefore, according to the crosstalk shutdown device of the present invention, there is provided an optical system having a plurality of input ports and a plurality of output ports for switching the coupling between these input ports and output ports. A crosstalk shutdown device used for a switch, wherein the crosstalk of signal light and crosstalk propagating through the input port and the output port is transmitted to the input port and / or the output port. It is provided so as to block and allow the signal light to pass through.

When such a crosstalk shutdown device is used, the signal light output from the output port can be transmitted and the crosstalk can be cut off. Therefore, the crosstalk generated by the optical switch can be reduced by an element provided at a subsequent stage. Can be blocked so as not to adversely affect the operation.

The crosstalk shut-down device according to the present invention is preferably provided at the input ports for monitoring the intensity of light input to these input ports, and provided at the output ports. Shutdown means for transmitting signal light output from the output port and blocking crosstalk output from these output ports, and switching of the intensity of light detected by the monitor means and coupling between the input port and the output port It is preferable to provide control means for controlling the shut-down means.

According to this configuration, all output ports of the optical switch are provided with the shutdown means for transmitting the signal light and cutting off the crosstalk. The monitoring means is provided for each of the input ports. The presence or absence of light input to the input port by this monitor means is transmitted to the control means. The control means operates the shutdown means at the timing when the light is detected by the monitor means. By each of these means, crosstalk generated from the optical switch can be substantially eliminated.

In a preferred configuration example of the crosstalk shutdown device according to the present invention, first monitor means provided at the input ports for detecting the intensity of light input to these input ports is provided at the input port. Intensity control means for adjusting the intensity according to the intensity of light detected by the first monitor means provided at the input ports; and the intensity control means provided at the input ports and provided at the input ports. (1) First shutdown means for blocking the light input to these input ports in accordance with the intensity of light detected by one monitor means, provided in the output port for detecting the intensity of light output from these output ports A second monitoring means, and a light intensity detected by the second monitoring means provided at the output ports and provided at the output ports. Is good comprises a second shutdown means for detecting the intensity of light output from these output ports in accordance with the.

According to this configuration example, the first monitor means for detecting the intensity of the input light is provided at all the input ports of the optical switch. The intensity control means provided at each input port adjusts the intensity of the signal light input to the input port to a constant magnitude according to the magnitude of the signal detected by the first monitor means. Therefore, the intensity of the signal light input to each input port is adjusted to a constant value. Further, the first shutdown means provided for each input port includes a first shutdown means.
According to the magnitude of the signal detected by the monitor means, the signal light input to the input port is transmitted, but the crosstalk is cut off.

Further, all output ports of the optical switch are provided with second monitor means for detecting the intensity of the input light. The second shutdown means provided at each output port transmits the signal light output from the output port according to the magnitude of the signal detected by the second monitoring means, but blocks the crosstalk. Therefore, crosstalk generated from the optical switch can be substantially eliminated.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the drawings schematically show the configuration, arrangement relationship, and connection relationship to the extent that the present invention can be understood, and the conditions such as numerical values described below are merely examples. Is not limited to this embodiment at all.

[First Embodiment] FIG. 1 is a block diagram for explaining a configuration of a crosstalk shutdown device according to an embodiment. The crosstalk shutdown device 10 is configured to be used by being connected to the optical matrix switch 100. As is well known, the optical switch 100 includes a plurality of input ports and a plurality of output ports, and is configured to switch the coupling between the input ports and the output ports. In this example, a 4 × 4 matrix optical switch 100 is used as such an optical switch. The 4 × 4 matrix optical switch 100 has four input ports I1, I2, I3, and I4 and four output ports O1, O2, O3, and O4 as line interfaces. An optical fiber as a light propagation path is coupled to each input port, and light is input through these optical fibers. Optical fibers are also coupled to each output port, and light is output from these optical fibers.

According to the present invention, the crosstalk shut-down device is configured to transmit the crosstalk and the signal light propagating through the input port and the output port to at least one of the plurality of input ports and the plurality of output ports of the optical switch. Among them, it is provided so as to block crosstalk and allow signal light to pass. For this reason, in this configuration example, the crosstalk shutdown device 10
It comprises four monitor means 12, 14, 16, 18; four shutdown means 20, 22, 24, 26; and control means 28.

The monitoring means of the configuration example shown in FIG. 1 is a first light detecting device 12, a second light detecting device 14, a third light detecting device 16, and a fourth light detecting device 18. The input ports I1, I2, I3 and I
4. More specifically, it is provided in the optical propagation path connected to these input ports, that is, in the middle of the optical fiber. That is, the light transmitted from outside through the optical fiber is input to each input port after passing through each monitor. Each monitor means is a device for detecting the intensity of light input to these input ports. The monitor means is configured to detect the intensity of the input light by, for example, reflecting a part of the input light and receiving the reflected light with a light receiver such as a photodiode. Have been.

The shutdown means is a first optical shutdown device 20, a second optical shutdown device 22, a third optical shutdown device 24, and a fourth optical shutdown device 26. These shutdown devices are output ports O1, O2, O3, respectively. And O4, more specifically, provided in the middle of an optical propagation path, that is, an optical fiber connected to these output ports. That is, the light output from each output port of the optical switch 100 is configured to be input to the shutdown means provided at each output port. Each of the shutdown units is a device that transmits the signal light output from the output port and cuts off the crosstalk output from the output port.

The control means is a control device 28 which receives a signal from the monitor means and controls the optical switch and the shutdown means. That is, the control device 28 is a device that controls the shutdown unit in accordance with the intensity of the light detected by the monitor unit and the switching of the coupling between the input port and the output port by the optical switch. As shown in FIG. 1, the control device 28 includes a detection signal receiving unit 30, a switching setting unit 32, and a shutdown control unit 34.

The detection signal receiving section 30 is connected to each monitor 1
This is a part for receiving a detection signal and a non-detection signal sent from 2, 14, 16, and 18. Each monitor transmits a detection signal or a non-detection signal to the detection signal receiving unit 30 in accordance with the input of light that propagates through the optical fiber from the outside. The monitor means of this configuration example always transmits a non-detection signal (for example, a low-level signal: an L signal) to the detection signal receiving unit 30 when no signal light is input. When signal light is input to any of the monitoring means,
The monitoring means sends a detection signal (for example, a high-level signal or a high-level pulse signal) to the detection signal
H signal). In response to the timing at which the signal light is input, that is, the timing at which the detection signal is received by the detection signal receiving unit 30, the detection signal receiving unit 30 informs the shutdown control unit 34 of which input port the signal light has been input to. Is transmitted.

FIG. 10 is a block diagram showing an example of the configuration of the detection signal receiving section 30. The detection signal receiving unit 30 receives an electrical signal corresponding to the intensity of the optical signal detected by the monitor unit, checks the intensity of the signal, and determines whether or not the input light is signal light. It has a part 31. A signal level threshold value (reference level: REF) is set in advance in the determination unit 31. The signal input to the detection signal receiving unit 30 is compared with the threshold value, and the signal light is determined. Or crosstalk.
If it is signal light, it outputs a first determination signal indicating that signal light has been detected, and if it is crosstalk, it outputs a second determination signal indicating that crosstalk has been detected and signal light has not been detected. It shall be.

Next, information such as how to switch the optical switch 100 is set in the switch setting section 32. Switching of the optical switch 100, that is, switching of coupling between an input port and an output port will be described with reference to, for example, FIG.

FIG. 2 is a block diagram for explaining the operation of the crosstalk shutdown device. FIG. 2 shows an example in which the signal light S is input to the input port I1, the signal light S is switched by the optical switch 100, and is output to the output port O2. The switching setting unit 32 detects “which input port has the signal light input” and responds to the detection of this signal to output “the signal light input to a certain input port from which output port”. The switching information for operating the optical switch by designating "?" Is stored. The information stored in the switch setting unit 32 can be changed from outside as needed. As the switching setting section 32 and the switching information itself, conventionally known information may be used. However, in the present invention, the switching setting unit 32 is configured to transmit the signal corresponding to the switching information to the shutdown control unit 34 in synchronization with, for example, the output of the above-described first and second determination signals. , Has been configured.
For example, the detection signal from the monitor means is transmitted to the detection signal receiving unit 3
The data can be sent to the switching setting unit 32 via 0 to take timing.

The shutdown control unit 34 controls the shutdown means according to the signals output from the detection signal receiving unit 30 and the switching setting unit 32 described above. FIG.
, The first input port I1 to the second output port O2
An example in which an optical signal is switched and output will be described. In this case, since the signal light is input to the first input port I1, the first light detection device 12 detects the signal light and sends a detection signal to the detection signal receiving unit 30. Also,
Since no signal light is input to other input ports than the first input port, the second, third, and fourth photodetectors 14,
Each of 16 and 18 sends a non-detection signal to the detection signal receiving unit 30. Further, as described above, the switching setting unit 3
2, the light input to the input port I1 is output to the output port O.
2 is set so as to be combined. And
The shutdown control unit 34 receives information from the detection signal receiving unit 30 indicating to which input port light has been input, that is, a first determination signal, and information from the switching setting unit 32 indicates how the optical switch 10 performs switching. And receive. By receiving such information, the shutdown control unit 34 recognizes to which output port the signal light is output. Then, a signal for operating the shutdown means corresponding to the recognition is transmitted to the shutdown means.

In the example of FIG. 2, the shutdown control unit 34
Receives information that light has been input to the input port I1 and information that the light input to the input port I1 has been output to the output port O2. Then, the shutdown control unit 34 sends a signal to the second optical shutdown device 22 to transmit the input light. on the other hand,
The shutdown control unit 34 sends a signal to the shutdown means other than the second optical shutdown device 22, that is, the first, third, and fourth optical shutdown devices 20, 24, and 26 to shut off the input light. .

Therefore, the second optical shutdown device 22
Allows the signal light output from the output port O2 to pass therethrough, and outputs the signal light to the outside, that is, to an element provided at a subsequent stage of the optical switch 100. Also, the first, third and fourth optical shutdown devices 20, 24 and 26
Prevents light output from the output ports O1, O3 and O4 from being output to the outside. In this example, the output ports O1, O3, and O4 from which the signal light S is not output are connected to the crosstalks C1, C1,
Although C2 and C3 are output, these crosstalks C1, C2 and C3 are caused by the shutdown device 20,
It can be seen that no output is made to the outside by the action of 24 and 26.

As described above, according to the crosstalk shutdown device of this configuration example, it is possible to substantially prevent the crosstalk that has been output after the optical switch from being output. Therefore, according to this configuration,
The crosstalk suppression of the optical switch is greatly improved as compared with the related art. Further, as described above, since the control of the shutdown means is easy, it is possible to eliminate the need for a great adjustment as in the related art. Therefore, the maintainability of the optical switch is improved. Also, since the shutdown means is added only one by one to the output port of the optical switch, it is possible to easily cope with an increase or decrease in the switch size.

FIG. 3 is a block diagram showing an example of the configuration of the shutdown means. The shutdown means shown in FIG. 3 includes an O / E converter 36, a switch 38, and an E / O
A converter 40 is provided. The O / E converter 36 converts an input optical signal into an electric signal.
A light receiver such as a photodiode having a photoelectric conversion function is used. The E / O converter 40 is an element that converts an electric signal into an optical signal, and for example, a light emitting diode or a laser diode is used. The switch 38 is an element that cuts off an output signal from the O / E converter 36 according to a signal sent from the control device 28, that is, the shutdown control unit 34 in this case. That is, if the signal sent from the control device 28 is information indicating that the input light should be blocked, the switch 38 outputs the output signal of the O / E converter 36 to the E / O converter 40 side. Work not to let it. The switch 38 can be configured using, for example, a transistor that inputs the above-described information as a control signal to a control electrode.

The shut-down means is not limited to the above-mentioned configuration, but may be, for example, an optical attenuator that operates in response to a signal from the control device 28. The optical attenuator operates to attenuate incident light in response to a signal from the control device 28.

[Second Embodiment] Next, the configuration of a second embodiment will be described.

FIG. 4 is a block diagram showing the configuration of the crosstalk shutdown device according to this embodiment. still,
Although some connections are omitted in FIG. 4, details are shown in FIGS. 5 and 6. Also in this example, the case where the 4 × 4 matrix optical switch 100 is used as the optical switch will be described. Further, the crosstalk shutdown device of this configuration example also provides the crosstalk and the signal light of the crosstalk and the signal light propagating through the input port and the output port to the plurality of input ports and the plurality of output ports. Is provided so as to block the signal light and allow the signal light to pass therethrough.

The crosstalk shutdown device 110 of this configuration example includes four first monitor means, four intensity control means, four first shutdown means, two second monitor means, and two second shutdown means. I have. The first monitoring means, the intensity control means, and the first shutdown means are provided in an input port, that is, in the middle of an optical fiber connected to the input port. The second monitoring means and the second shutdown means are provided in the output port, that is, in the middle of the optical fiber connected to the output port.

The first monitoring means in the configuration example shown in FIG. 4 is a first light detecting device 112, a second light detecting device 114, a third light detecting device 116, and a fourth light detecting device 118. The monitor means is provided for each input port I
1, I2, I3 and I4. Light transmitted from the outside through the optical fiber is input to the intensity control means provided in the next stage after passing through each first monitor means. The first monitor is a device that detects the intensity of light input to each of the input ports I1, I2, I3, and I4. As the first monitoring means, for example, a light receiver such as a photodiode is used.

As the first monitoring means, the monitoring means described in the first embodiment may be used. Although the monitoring means of the first embodiment is configured to send a detection signal or a non-detection signal to the control device 28, in this case, these signals are sent to the corresponding first shutdown means. What is necessary is just to configure.

The intensity control means includes a first light intensity controller 42,
A second light intensity controller 44, a third light intensity controller 46, and a fourth light intensity controller 48, and these intensity control means are provided at input ports I1, I2, I3, and I4, respectively. Each of the first, second, third, and fourth light intensity controllers 42, 44, 46, and 48 is provided at the next stage of the first, second, third, and fourth light detection devices, respectively. I have. That is, the light that has passed through the first, second, third, and fourth light detection devices 112, 114, 116, and 118 is converted into first, second, third, and fourth light intensity controllers 42, 44, and 46, respectively. And 48, respectively. These intensity control means are means for adjusting the intensity of light input to each input port according to the intensity of light detected by the first monitor means.

The light intensity is adjusted by the second monitor means (50, 52, 5) provided on the output port side.
4 and 56) in order to facilitate discrimination between crosstalk and signal light. In the second monitor, the discrimination between the crosstalk and the signal light is performed according to the intensity of the input light. Therefore, the intensity control unit (intensity control means) controls the crosstalk and the signal light input to the second monitor. Is adjusted so that the intensity ratio (S / N ratio) becomes a desired value.

The first shutdown means includes a first optical shutdown device 120 and a second optical shutdown device 12.
A second optical shutdown device 124, a fourth optical shutdown device 126, and these shutdown means include input ports I1, I2, I3, and I4, respectively.
Is provided. Further, the above-described intensity control means 42, 44,
The light output from 46 and 48 is respectively transmitted to the first, second, third, and fourth light shutdown devices 120, 12
2, 124 and 126. Then, each of the first shutdown means 120, 12
Lights output from 2, 124 and 126 are input to input ports I1, I2, I3 and I4, respectively. These first shut-down means are devices for blocking light input to these input ports in accordance with the intensity of light detected by the first monitor means.

The second monitoring means includes a fifth light detecting device 50, a sixth light detecting device 52, a seventh light detecting device 54, and an eighth light detecting device 56.
They are provided at output ports O1, O2, O3 and O4, respectively. That is, the light output from each output port is input to the second monitor means provided in the corresponding port. The second monitor is a device that detects the intensity of light output from the output port. still,
The second monitoring means may have the same configuration as the first monitoring means. Then, the detection signal or the non-detection signal output from the second monitoring means is configured to be input to the corresponding second shutdown means.

Further, the second shutdown means includes a fifth shut-down means.
An optical shutdown device 58, a sixth optical shutdown device 60, a seventh optical shutdown device 62, and an eighth optical shutdown device 64. These second shutdown means include output ports O1, O2, O3, and O, respectively.
4. Further, these second shut-down means are provided next to the above-mentioned second monitor means. That is, the second shutdown means is provided such that the light output from the second monitoring means is incident on the corresponding second shutdown means. The light output from the output ports O1, O2, O3, and O4 is input to the optical shutdown devices 58, 60, 62, and 64, respectively. These second shutdown units are devices that detect the intensity of light output from the corresponding output port in accordance with the intensity of light detected by the second monitoring unit.

FIG. 5 is a block diagram showing a detailed configuration of the first monitoring means, the intensity control means and the first shutdown means. As shown in FIG.
Of the crosstalk shutdown device provided on the input port side of the O / E converter 36 and the monitor unit 6
6, an alarm generator 68, an intensity adjuster 70, a switch 38, and an E / O converter 40. Then, the photodetectors 112, 11 constituting the first monitor means
4, 116 and 118 each include an O / E converter 36,
It comprises a monitor section 66 and an alarm generator 68. Each of the intensity control means 42, 44, 46 and 48 is configured as an intensity adjustment unit 70. Also, the first
Shutdown means 120, 122, 124 and 12
6 is composed of a switch 38 and an E / O converter 40.

The optical signal input to the O / E converter 36 is
The signal is converted into an electric signal and input to the monitor 66. The monitor unit 66 is a device that detects the intensity of the optical signal input to the O / E converter 36 by detecting the intensity of the input electric signal.

The monitor 66 outputs a signal corresponding to the intensity of the input optical signal to the alarm generator 68. The alarm generator 68 outputs the electric signal input from the monitor unit 66 to the intensity adjustment unit 70, and outputs an alarm signal to the switch 38 according to the intensity of the electric signal input from the monitor unit 66. That is, the O / E converter 36
Since the electric signal corresponding to the signal light is larger than the threshold level (reference level) when the light input to the signal generator is the signal light, the alarm generator 68 sets the electric signal level to the threshold value. And an alarm signal is generated. On the other hand, when the level of the input electric signal is lower than the threshold value, no alarm signal is generated. As described above, the O / E converter 36, the monitor unit 66, and the alarm generator 68 correspond to the above-described first monitor means (112, 114, 116, or 118).

The electric signal input to the intensity adjusting unit 70 is
When the electric signal corresponds to the signal light, the intensity is adjusted by the intensity adjusting unit 70 to a fixed size and output. The electric signal that has passed through the intensity adjustment unit 70 is input to the switch 38. The intensity adjusting unit 70 includes the above-described intensity control units 42, 44, and 46.
And 48.

The switch 38 controls the intensity adjustment unit 70 and the E / O according to the presence or absence of the above-mentioned alarm signal.
An element for electrically connecting and disconnecting the converters 40. The switch 38 is connected when an alarm signal is input, and is disconnected when no alarm signal is input. That is, the switch 38 is connected only when the light input to the O / E converter 36 is a signal light. Therefore, only when the light input to the O / E converter 36 is a signal light, the electric signal is output from the E / O converter 40.
Is input to Then, the electric signal is converted by the E / O converter 40 into an optical signal having a size corresponding to the electric signal and output. This optical signal is input to the input port. Thus, switch 38 and E
The / O converter 40 corresponds to each of the first shutdown means 120, 122, 124 and 126 described above.

Incidentally, the intensity control means may be provided with an E / O converter so that the optical signal whose intensity is adjusted is output to the corresponding first shutdown means. In this case, the first shutdown means may be constituted by an optical attenuator or an optical amplifier that operates according to the presence or absence of the above-mentioned alarm signal.

Further, the first monitor means is, like the monitor means described in the first embodiment, for example, to take out only a part of the input light, and A configuration in which light is received by a light receiver such as a diode may be used. In this case, it is preferable that the intensity control means is constituted by an optical attenuator or an optical amplifier as described above, and the intensity control means is operated by a signal output from the light receiver.

FIG. 6 is a block diagram showing an example of a detailed configuration of the second monitor means and the second shutdown means. As shown in FIG. 6, the configuration of the crosstalk shutdown device provided on the output side is the same as the configuration described with reference to FIG. 5, except that the intensity adjustment unit 70 is omitted. That is, the electric signal output from the alarm generator 68 is directly input to the switch 38. In FIG. 6, each second monitor means 50, 52, 54
And 56 correspond to the O / E converter 36, the monitor 66, and the alarm generator 68, and each of the second shutdown means 58, 60, 62 and 64 includes a switch 38.
And the E / O converter 40.

In the case of the configuration shown in FIG.
8 generates an alarm signal according to the strength of the signal input to the O / E converter 36. The intensity of the signal input to the O / E converter 36 is detected by the monitor 66. Then, the monitor 66 reports the detected light intensity to the alarm generator 68. Only when the light intensity corresponds to the signal light intensity, the alarm generator 68 outputs an alarm signal. The alarm signal is input to the switch 38. The switch 38 passes the electric signal converted by the O / E converter 36 to the E / O converter 40 only when an alarm signal is input.

The second monitor means is, for example, to take out only a part of the input light, like the monitor means described in the first embodiment or the first monitor means described above. Alternatively, the extracted light may be received by a light receiver such as a photodiode. Then, the second shutdown means operates according to the output of the light receiver,
The light output from the second monitor means is transmitted or blocked.

FIG. 7 is a block diagram for explaining the operation of the crosstalk shutdown device described with reference to FIG. FIG. 7 shows a state where the signal light S1 is input to the input port I1, and the signal light S1 is switched by the optical switch 100 and output to the output port O2.

The first monitor means 112, 114, 11
When 6 and 118 are, for example, O / E converters constituted by photodiodes or the like, the outputs of these first monitoring means are electric signals. As described above, this electric signal is input to the corresponding intensity control means 42, 44, 46, 48, respectively. Each intensity control means changes the intensity of the input electric signal according to the electric signal output from the first monitor means. Then, for example, the intensity control means transmits the electric signal whose intensity has been adjusted to the corresponding first shutdown means 120, 122,
And outputs the same to 124 and 126 respectively. Therefore, FIG.
In, the path between the first monitoring means and the intensity control means is a path through which an electric signal is transmitted, and the optical signal S1 does not pass through as it is. However, for the sake of simplicity, the process of conversion into an electric signal is omitted, and FIG. 7 and FIG.
It is shown that the optical signal passes directly between the first monitoring means and the intensity control means. 7 and 8
In the above description, the notation of the signal between the second monitoring means and the second shutdown means is the same as the notation of the signal between the first monitoring means and the intensity adjusting means.

As shown in FIG. 7, the first photodetector 1
12, the signal light S1 is input. First photodetector 11
2 outputs a signal indicating that the signal light has been input to the corresponding intensity control means, that is, the first light intensity controller 42. Thus, each of the first monitor means 112, 114, 1
Each of 16 and 118 has a function of determining whether or not the input light is signal light based on the intensity of the input light. This determination can be made by comparing the detected light intensity with a set threshold value. Alternatively, such a function may be provided on the side of the intensity control means. Then, the first light intensity controller 42 adjusts the signal output from the first light detection device 112 so that the level of the signal light S1 input to the input port I1 has a certain intensity.

Further, as described above, the first light detecting device 112 is provided with the first shutdown means provided at the corresponding input port I1, that is, the first light shutdown device 12
For 0, the above-mentioned alarm signal is output. Therefore, the signal light S1 input to the first optical shutdown device 120 passes through the device 120, and the first input port I1
Is input to

The first monitoring means other than the first light detecting device 112, ie, the second, third and fourth light detecting devices 11
No signal light is input to 4, 116 and 118.
Therefore, the second, third and fourth photodetectors 11
4, 116 and 118 do not output an alarm signal to the corresponding first shutdown means 122, 124 and 126. Therefore, the first shutdown means, that is, the second, third and fourth optical shutdown devices 12
2, 124 and 126 operate to block incoming light. In this case, the second, third, and fourth
Like the light intensity controllers 44, 46, and 48, the intensity control means may be configured not to operate except when signal light is input.

Then, from the input port I1 to the optical switch 1
The signal light S1 input to 00 is switched so as to be output to the output port O2. A sixth light detection device 52 and a sixth light shutdown device 60 are provided at the output port O2 from which the signal light S1 is output. As described with reference to FIG. 6, since the electric signal level converted by the alarm generator 68 is higher than the threshold level, the sixth light detection device 52 is input from the optical switch 100. It detects that the generated light is signal light instead of crosstalk, and outputs the above-described alarm signal to the sixth optical shutdown device 60. Then, the sixth light shutdown device 60 passes the signal light S1 output from the output port O2 or the electric signal converted by the sixth light detection device 52 to the outside.

The other output ports O1, O3 and O3
4 outputs the crosstalks C1, C2 and C3 generated in the optical switch 100. In this case, the fifth, seventh, and eighth photodetectors 50, 54, and 56 provided at the output ports O1, O3, and O4 detect that crosstalk has been output from the output ports. Accordingly, since the signal level of the crosstalk is smaller than the threshold level, the fifth, seventh and eighth photodetectors 5
No alarm signal is generated from the alarm generators 68 of 0, 54 and 56. Therefore, in this case, the fifth and seventh
And the eighth optical shutdown devices 58, 62 and 64
Are in a closed state, impervious to signals, so that the devices 58, 62 and 64 provide crosstalk C1, C2
And C3.

Next, with reference to the block diagram of FIG. 8, an operation when signal light is simultaneously input to two input ports will be described. In FIG. 8, the signal light S is input to the input port I1.
1, the signal light S1 is switched by the optical switch 100 and output to the output port O2, the signal light S2 is input to the input port I3,
The state when the signal light S2 is switched by the optical switch 100 and output from the output port O1 is shown.

The signal light S1 input to the input port I1 is as described above. In this example, the signal light S2 is also input to the input port I3. Talks C4, C5 and C6 occur. These crosstalks C4, C5 and C6 are:
Output to the output ports O2, O3 and O4 respectively. Accordingly, the signal light S1 and the crosstalk C4 are output from the output port O2. Similarly, signal light S2 and crosstalk C1 are output from output port O1.

As described above, when signal light is input to two or more input ports, signal light and crosstalk are output from one output port. Even in such a case, similarly to the above, the second monitoring means detects that the light output from the output port is not a signal light, and instructs the corresponding second shutdown means to block the light or Instruct to transmit. That is, the second shutdown means 58 and 60 provided at the output ports O1 and O2 to which the signal light is output are made to transmit light, and the output port O to which the crosstalk is output is transmitted.
Second shutdown means 62 provided in 3 and O4
And 64 block the light.

As described above, according to this crosstalk shutdown device, the function of interrupting the optical switch so as not to input the crosstalk and the function of interrupting the crosstalk output from the optical switch so as not to be transmitted to the subsequent stage are provided. Have. Therefore, the switching characteristics of the optical switch are greatly improved. Also, since the shutdown means operates according to the intensity of light detected by the monitor means,
This eliminates the need for a large adjustment work as in the related art, and improves the maintainability of the optical switch. Also, since the shutdown means is added only one by one to the output port of the optical switch, it is possible to easily cope with an increase or decrease in the switch size.

In the first and second embodiments described above, a 4 × 4 matrix optical switch is used as an optical switch, but the crosstalk shutdown device is also effective for other optical switches. Further, the crosstalk shutdown device of the embodiment can be used together with another crosstalk suppression mechanism.

[0067]

According to the crosstalk shutdown device of the present invention, the crosstalk generated by the optical switch can be reduced.
In order not to adversely affect the elements provided at the subsequent stage,
Can be shut off. For example, in the case where an optical signal regenerator such as an optical amplifier is installed after the optical switch, crosstalk is amplified, and the light is received even when there is no signal light output from the corresponding output port. This prevents the crosstalk from being received as signal light in the section.

According to the crosstalk shutdown device of the present invention, all output ports of the optical switch are provided with shutdown means for transmitting signal light to cut off crosstalk. Further, monitor means are provided for all input ports, respectively, and notify the control means of the presence or absence of light input to the input ports. The control means operates the shutdown means at the timing when the light is detected by the monitor means. By each of these means, crosstalk generated from the optical switch can be substantially eliminated. As described above, since complicated adjustment is not required, it is easy to configure an optical circuit.

Further, according to the crosstalk shutdown device of the present invention, all input ports of the optical switch are provided with the first monitor means for detecting the intensity of input light. The intensity control means provided at each input port comprises a first
The intensity of the signal light input to the input port is adjusted to a constant value according to the magnitude of the signal detected by the monitor means. Therefore, the intensity of the signal light input to each input port is adjusted to a constant value. Therefore, even when the intensity of the optical signal input to the input port of the optical switch varies greatly, the problem that the S / N ratio at the light receiving unit such as the second monitor unit cannot be sufficiently obtained is solved.

The first shut-down means provided at each input port transmits the signal light input to the input port according to the magnitude of the signal detected by the first monitor means, and reduces crosstalk. Cut off. Further, second output means for detecting the intensity of input light is provided at all output ports of the optical switch. The second shut-down means provided at each output port transmits the signal light output from the output port according to the magnitude of the signal detected by the second monitor means, and cuts off crosstalk. Therefore, crosstalk generated from the optical switch can be substantially eliminated. Further, since such complicated adjustment is not required, it is easy to configure an optical circuit.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a crosstalk shutdown device according to a first embodiment.

FIG. 2 is a diagram provided for explanation of operation.

FIG. 3 is a diagram illustrating a configuration of a shutdown unit.

FIG. 4 is a diagram illustrating a configuration of a crosstalk shutdown device according to a second embodiment.

FIG. 5 is a diagram illustrating a partial configuration of a crosstalk shutdown device.

FIG. 6 is a diagram illustrating a partial configuration of a crosstalk shutdown device.

FIG. 7 is a diagram provided for explanation of operation.

FIG. 8 is a diagram for explaining the operation.

FIG. 9 is a diagram showing the influence of crosstalk.

FIG. 10 is a diagram illustrating a configuration of a detection signal receiving unit.

[Explanation of symbols]

 10, 110: crosstalk shutdown device 12, 112: first photodetector 14, 114: second photodetector 16, 116: third photodetector 18, 118: fourth photodetector 20, 120: first Optical shutdown device 22, 122: Second optical shutdown device 24, 124: Third optical shutdown device 26, 126: Fourth optical shutdown device 28: Control device 30: Detection signal receiving unit 31: Judgment unit 32: Switching setting unit 34 : Shutdown control unit 36: O / E converter 38: Switch 40: E / O converter 42: First light intensity controller 44: Second light intensity controller 46: Third light intensity controller 48: Fourth light Intensity controller 50: Fifth light detection device 52: Sixth light detection device 54: Seventh light detection device 56: Eighth light detection device 58: Fifth light shutdown device 6 : Sixth optical shutdown device 62: seventh optical shutdown device 64: 8 optical shutdown device 66: monitor 68: alarm generator 70: intensity adjustment unit 100: 4 × 4 matrix optical switch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshimi Kominato 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Masayasu Yamaguchi 3-19, Nishi-Shinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation (72) Inventor Kenichi Yukimatsu 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. A crosstalk shutdown device for use in an optical switch that has a plurality of input ports and a plurality of output ports and that switches the coupling between the input ports and the output ports, wherein the plurality of input ports are provided. And to both or one of the plurality of output ports, so as to cut off the crosstalk among crosstalk and signal light propagating through these input ports and output ports and to pass the signal light,
A crosstalk shutdown device provided. 2. The crosstalk shut-down device according to claim 1, wherein said monitor is provided at said input port and detects the intensity of light input to said input port; and said output port is provided at said output port. Means for transmitting the signal light output from the output port and blocking crosstalk output from these output ports, and according to the intensity of light detected by the monitor means and switching of coupling between the input port and the output port. And a control means for controlling the shutdown means. 3. The crosstalk shut-down device according to claim 1, wherein the first monitor is provided at the input port, and detects the intensity of light input to the input port. Intensity control means for adjusting the intensity according to the intensity of light detected by the first monitor means provided at the input port; provided at the input port; detection by the first monitor means provided at these input ports First shutdown means for blocking the light input to these input ports in accordance with the intensity of the light, second monitor means provided at the output port, and detecting the intensity of light output from these output ports; These output ports are provided at the output ports according to the intensity of light detected by the second monitoring means provided at the output ports. Crosstalk shutdown apparatus characterized by comprising a second shutdown means for detecting the intensity of light et output.