JP4579024B2 - Method and apparatus for stabilizing optical output of optical switch - Google Patents

Description

  The present invention determines an output path of a light beam in an optical switch that continuously reflects a light beam input from an arbitrary input port between a plurality of input / output ports by a plurality of mirrors and outputs the light beam to an arbitrary output port. The present invention relates to a light output stabilization method and apparatus for an optical switch that finely adjusts the angles of a plurality of mirrors to stabilize output light intensity.

  FIG. 8 shows a configuration example of the optical switch. In the figure, the optical switch has a configuration in which two collimator arrays 1a and 1b in which a plurality of collimators are two-dimensionally arranged and two mirror arrays 2a and 2b in which a plurality of reflective mirrors are two-dimensionally arranged. . An input optical fiber array in which a plurality of optical fibers are two-dimensionally arranged corresponding to each collimator is connected to the input collimator array 1a, and an output collimator array 1b is associated with each collimator. An output optical fiber array in which a plurality of optical fibers are two-dimensionally arranged is connected. The angle of each mirror is controlled by MEMS (Micro Electric Mechanical System) technology, and any input / output optical fiber can be connected (switching the output path) by combining the mirrors reflected by the two mirror arrays 2a and 2b. It is possible.

  By the way, a predetermined angle corresponding to the output path is preset for each mirror, but the incident angle or the incident position of the light beam with respect to the collimator (output port) on the output side is minute due to minute fluctuations in the angle of each mirror. And the output light intensity may fluctuate. As a method for stabilizing such fluctuations in output light intensity, there is a method in which the output light intensity is monitored and the angle of each mirror is finely adjusted so that the output light intensity is maximized. At this time, a method of adjusting the angle of each mirror in the x-axis direction and the y-axis direction while monitoring the output light intensity, and a method of adjusting the angle so that the output light intensity is maximized by changing each mirror in a spiral angle. Etc. are used.

A method is also known in which a photoreceiver array is arranged on the output side, and the optimum incident position and angle are adjusted by measuring the incident position and angle from the beam shape reaching the photoreceiver array (Patent Document 1). ).
JP 2002-236264 A

  Depending on the structure of the optical switch, for example, even if the angle is set so that the output light intensity at the output port is maximized for two mirrors, it is necessary to repeat fine adjustment thereafter. At this time, as shown in FIG. 9, when the angle of the first mirror 4a is shifted, the incident angle and the incident position on the output port (output-side collimator 3b) change. Therefore, conventionally, fine adjustment is performed so that the output light intensity at the output port is always maximized by adjusting the angle of the second mirror 4b corresponding to the angle adjustment of the first mirror 4a. However, since the first mirror and the second mirror are finely adjusted independently, the output light intensity at the output port fluctuates with each fine adjustment of the respective mirrors until the output light intensity becomes stable. It took a certain amount of time.

  In an optical switch that switches the output path of a light beam by controlling the angles of a plurality of mirrors between a plurality of input / output ports, the angle of each mirror is controlled so that the output light intensity at the output port is maximized. An object of the present invention is to provide a method and an apparatus for stabilizing the optical output of an optical switch which can be performed at high speed and can obtain a stable output light intensity.

The first invention relates to an optical switch that continuously reflects a light beam input from an arbitrary input port between a plurality of input / output ports by a plurality of mirrors and outputs the light beam to an arbitrary output port. In the optical output stabilization method of an optical switch that stabilizes the output light intensity by finely adjusting the angles of the plurality of mirrors that determine the output path so that the output light intensity is maximized, the output of the output port from which the light beam is output Monitor the light intensity, detect the control amount corresponding to the angular displacement of the multiple mirrors when the output light intensity becomes maximum when the angle of the multiple mirrors is slightly displaced, and obtain the control amount of each mirror obtained Is calculated as a correction coefficient, and when adjusting the angle of the multiple mirrors, the angle of the predetermined mirror is displaced using the correction coefficient so that the displacement amount of the multiple mirror angles has a predetermined relationship. Control amount Conjunction with setting the control amount to displace the angle of the other mirrors.

  Here, the correction coefficient update process may be performed at a predetermined timing while interlocking controlling fine adjustment of the angles of the plurality of mirrors using the correction coefficient. In addition, control light with a wavelength different from that of signal light that switches the output path between multiple input / output ports via an optical switch is prepared, and the control light is combined with the signal light by an optical coupler placed at the input port for output. The signal light and the control light may be demultiplexed by a WDM coupler arranged at the port, and the light intensity of the demultiplexed control light may be monitored. In addition, control light with a wavelength different from that of signal light that switches the output path between multiple input / output ports via an optical switch is prepared, and the control light is combined with the signal light by a WDM coupler placed at the input port for output. The signal light and the control light may be demultiplexed by a WDM coupler arranged at the port, and the light intensity of the demultiplexed control light may be monitored.

According to a second aspect of the present invention, a light beam input from an arbitrary input port between a plurality of input / output ports is continuously reflected by a plurality of mirrors and output to an arbitrary output port. In the optical output stabilization device of the optical switch that stabilizes the output light intensity by finely adjusting the angle of the multiple mirrors that determine the output path so that the output light intensity is maximized, the output of the output port from which the light beam is output Monitor the light intensity, detect the control amount corresponding to the angular displacement of the plurality of mirrors when the output light intensity becomes maximum when the angle of the plurality of mirrors is slightly displaced, and control the obtained mirrors The ratio of the amount is calculated as a correction coefficient, and when the angle of the plurality of mirrors is finely adjusted, the angle of the predetermined mirror is set using the correction coefficient so that the displacement amount of the angle of the plurality of mirrors has a predetermined relationship. Displacement control In conjunction with the amount comprises control means for setting a control amount to displace the angle of the other mirrors.

  Here, the control means may be configured to update the correction coefficient at a predetermined timing while interlocking controlling fine adjustment of the angles of the plurality of mirrors using the correction coefficient. In addition, a control light source that outputs control light having a wavelength different from that of the signal light that switches the output path between the plurality of input / output ports via an optical switch is provided, and an optical coupler that combines the control light with the signal light is provided at the input port. A WDM coupler that demultiplexes the signal light and the control light may be disposed at the output port, and the control unit may monitor the light intensity of the control light demultiplexed by the WDM coupler. In addition, a control light source that outputs control light having a wavelength different from that of the signal light that switches the output path between the plurality of input / output ports via an optical switch is provided, and a WDM coupler that combines the control light with the signal light is provided at the input port A WDM coupler that demultiplexes the signal light and the control light may be disposed at the output port, and the control unit may monitor the light intensity of the control light demultiplexed by the WDM coupler.

  In the present invention, for a plurality of mirrors according to the output path, by adjusting the control amount for displacing the angle of one mirror and the other mirror, the incident position to the output port is adjusted and the incident position is adjusted, Stable output light intensity can be obtained at high speed.

  In the present invention, the ratio of the control amounts corresponding to the angular displacement of the plurality of mirrors when the output light intensity becomes maximum when the angles of the plurality of mirrors are slightly displaced from the initial setting values according to the output path. When calculating the correction coefficient corresponding to, and fine-adjusting the angle of multiple mirrors, the control angle of one mirror and the other mirror is linked and controlled using the correction coefficient, so that the incident angle to the output port is The incident position can be adjusted while maintaining a constant output light intensity at high speed.

  Thereby, high-speed switching of the optical switch and stabilization of the output light intensity are possible, and the stability of the optical network using the optical switch can be improved.

(First Embodiment of Optical Output Stabilizing Device for Optical Switch)
FIG. 1 shows a first embodiment of an optical output stabilizing device for an optical switch according to the present invention. Here, of the two collimator arrays 1a and 1b and mirror arrays 2a and 2b of the optical switch shown in FIG. 8, one set of collimators 3a and 3b corresponding to a predetermined input / output port and one set of mirrors 4a and 4b. Show only.

  The optical signal input from the input port 5a is output to the corresponding output port 5b via the collimator 3a, the mirrors 4a and 4b, and the collimator 3b of the optical switch 10. The optical signal output to the output port 5 b is partially branched by the optical coupler 6 and converted into an electrical signal by the light receiver 7. This electric signal is input to the control circuit 8, and a control amount to be given to the mirror driving circuits 9a and 9b for controlling the angles of the mirrors 4a and 4b is determined.

(First embodiment of optical output stabilization method of optical switch)
FIG. 2 shows a first embodiment of the optical output stabilization method of the optical switch of the present invention. In the apparatus configuration shown in FIG. 1, the control circuit 8 controls the angles of the mirrors 4a and 4b according to the output path to be set to the initial set values via the mirror drive circuits 9a and 9b (S1). Next, the angle of each mirror is displaced, and the control amounts Va and Vb with respect to the displacement of the angle of the mirrors 4a and 4b at which the output light intensity at the output port 5b is maximized are detected (S2). For example, the control amount when the mirror 4a is displaced from the initial set value by a minute angle is Va, and the angle of the mirror 4b is further displaced from the initial set value, and the output light intensity at the output port 5b is maximized. The control amount 4b is detected as Vb. Next, the ratio between the control amounts Va and Vb of the mirrors 4a and 4b is calculated as a correction coefficient M (= Vb / Va) (S3). Next, when finely adjusting the angles of the mirrors 4a and 4b, the angles of the mirrors 4a and 4b are controlled in conjunction with the control amount using the correction coefficient M calculated in step S3 (S4). For example, as shown in FIG. 1, when the control amount of the fine adjustment angle of the mirror 4a is Va ′, the control amount of the fine adjustment angle of the mirror 4b is set as M × Va ′. As a result, the interlocking control is performed so that the angular displacement amounts of the mirrors 4a and 4b have a predetermined relationship (for example, become equal).

  FIG. 3 shows an example of the processing procedure up to the calculation of the correction coefficient. Here, the calculation processing procedure of the correction coefficient Mx in the x-axis direction of the mirrors 4a and 4b is shown, but the calculation processing procedure of the correction coefficient My in the y-axis direction is the same. This processing procedure corresponds to the processing in steps S2 and S3 of the flowchart shown in FIG.

  The control circuit 8 instructs the mirror drive circuit 9a of the mirror 4a with a control amount Vxa for giving an angular displacement with respect to the initial set value in the x-axis direction for reflection on the mirror 4b according to the position of the output port 5b. (S11). The mirror drive circuit 9a sets the control amount Vxa in the mirror 4a according to this instruction (S12). The mirror 4a changes in the x-axis direction by an angle corresponding to the control amount Vxa (S13). Next, the control circuit 8 controls the angle of the mirror 4b in the x-axis direction so as to maximize the output light intensity while monitoring the output light intensity at the output port 5b with the light receiver 7. At this time, the control amount for giving the angular displacement from the initial set value in the x-axis direction instructed to the mirror drive circuit 9b of the mirror 4b is set to Vxb (S14). Next, Vxb / Vxa is calculated as a correction coefficient Mx in the x-axis direction from the control amounts Vxa and Vxb giving the angular displacement in the x-axis direction of the mirrors 4a and 4b (S15).

  Similarly, the correction coefficient My in the y-axis direction is calculated. That is, after changing the mirror 4a in the y-axis direction by an angle corresponding to the control amount Vya from the initial set value, the mirror 4b is angle-controlled in the y-axis direction to determine the control amount Vyb that maximizes the output light intensity. Then, Vyb / Vya is calculated as a correction coefficient My in the y-axis direction from the control amounts Vya and Vyb in the y-axis direction of the mirrors 4a and 4b.

  Next, when the mirrors 4a and 4b are finely adjusted, the correction coefficient Mx (= Vxb / Vxa) and My (= Vyb / Vya) obtained by the processing procedure shown in FIG. Are set as Mx × Vxa ′ and My × Vya ′ as control amounts of the mirror 4b. Thereby, as shown in FIG. 4, the mirrors 4a and 4b can adjust only the incident position while keeping the incident angle to the collimator 3b corresponding to the output port 5b constant. As described above, when the mirrors 4a and 4b are finely adjusted, by performing the interlock control using the correction coefficient, the mirrors 4a and 4b can be finely adjusted at high speed. Therefore, the maximum output light intensity in the output optical fiber 5b can be obtained quickly, and a stable output light intensity can be maintained.

(Second Embodiment of Optical Output Stabilization Method of Optical Switch)
FIG. 5 shows a second embodiment of the optical output stabilization method of the optical switch of the present invention. In the apparatus configuration shown in FIG. 1, the control circuit 8 controls the angles of the mirrors 4a and 4b according to the output path to be set to the initial set values via the mirror drive circuits 9a and 9b (S1). Next, the angle of each mirror is displaced, and the control amounts Va and Vb with respect to the displacement of the angle of the mirrors 4a and 4b at which the output light intensity at the output port 5b is maximized are detected (S2). Next, the ratio between the control amounts Va and Vb of the mirrors 4a and 4b is calculated as a correction coefficient M (= Vb / Va) (S3). Next, when finely adjusting the angles of the mirrors 4a and 4b, the angles of the mirrors 4a and 4b are controlled in conjunction with the control amount using the correction coefficient M calculated in step S3 (S4). The process up to this point is the same as in the first embodiment.

  The present embodiment is characterized in that the correction coefficient is updated by returning to step S2 every predetermined time while finely adjusting the angles of the mirrors 4a and 4b using the correction coefficient. Then, the angles of the mirrors 4a and 4b are linked and controlled using the updated correction coefficient (S4). Thereby, the correction coefficient changed by an external factor can always be maintained at an optimum value. In addition, you may return to step S1 and perform from the initial setting of the angle of each mirror for every progress of predetermined time.

(Second Embodiment of Optical Output Stabilizing Device for Optical Switch)
FIG. 6 shows a second embodiment of the optical output stabilizing device for an optical switch of the present invention. The feature of the present embodiment is that the signal light to be switched (wavelength λs) is not used as the light to be monitored for adjusting the angle of the mirror of the optical switch 10 or calculating the correction coefficient, and control of the wavelength λc different from the signal light. The place where light is used.

  In the figure, the control light output from the control light source 11 is combined with the signal light via the optical coupler 12 disposed in the preceding stage of the optical switch 10, input to the optical switch 10, and output together with the signal light. A WDM coupler 13 for demultiplexing the signal light and the control light is disposed at the subsequent stage of the optical switch 10, the signal light is input to the output port 5 b, and the control light is input to the light receiver 7. Processing related to the adjustment of the mirror angle of the optical switch 10 and the calculation of the correction coefficient is performed in the same manner as in the first embodiment by the control circuit 8 and the mirror drive circuits 9a and 9b. By using such control light, the calculation of the correction coefficient and the angle adjustment of the mirror can be performed without being affected even when the intensity of the signal light changes.

(Third embodiment of optical output stabilizing device of optical switch)
FIG. 7 shows a third embodiment of the optical output stabilizing device for an optical switch of the present invention. The feature of this embodiment is that a WDM coupler 14 is used in place of the optical coupler 12 that combines signal light and control light in the second embodiment. Other configurations are the same as those of the second embodiment. Thereby, the loss at the time of multiplexing of signal light and control light can be reduced, and an output light intensity greater than that of the configuration of the second embodiment can be obtained.

The figure which shows 1st Embodiment of the optical output stabilization apparatus of the optical switch of this invention. The flowchart which shows 1st Embodiment of the optical output stabilization method of the optical switch of this invention. The flowchart which shows an example of the process sequence until calculation of a correction coefficient. The figure explaining the example of angle control by this invention. The flowchart which shows 2nd Embodiment of the optical output stabilization method of the optical switch of this invention. The figure which shows 2nd Embodiment of the optical output stabilization apparatus of the optical switch of this invention. The figure which shows 3rd Embodiment of the optical output stabilization apparatus of the optical switch of this invention. The figure which shows the structural example of an optical switch. The figure explaining the conventional angle control example.

Explanation of symbols

1a, 1b Collimator array 2a, 2b Mirror array 3a, 3b Collimator 4a, 4b Mirror 5a Input port 5b Output port 6, 12 Optical coupler 7 Receiver 8 Control circuit 9a, 9b Mirror drive circuit 10 Optical switch 11 Control light source 13, 14 WDM coupler

Claims (8)

A plurality of optical beam output paths for an optical switch that continuously reflects a light beam input from an arbitrary input port between a plurality of input / output ports by a plurality of mirrors and outputs the light beam to an arbitrary output port. In the optical output stabilization method of the optical switch that finely adjusts the angle of the mirror so that the output light intensity becomes maximum and stabilizes the output light intensity,
Monitor the output light intensity of the output port from which the light beam is output, and control corresponding to the angular displacement of the plurality of mirrors when the output light intensity becomes maximum when the angle of the plurality of mirrors is slightly displaced Detect the amount, calculate the ratio of the control amount of each obtained mirror as a correction coefficient,
When finely adjusting the angles of the plurality of mirrors, the correction coefficient is used to interlock the control amount for displacing the predetermined mirror angle so that the displacement amounts of the plurality of mirror angles have a predetermined relationship. And setting a control amount for displacing the angle of the other mirror. In the optical output stabilization method of the optical switch according to claim 1,
The method for stabilizing the optical output of an optical switch, wherein the correction coefficient is updated at a predetermined timing while controlling fine adjustment of the angles of the plurality of mirrors using the correction coefficient. In the optical output stabilization method of the optical switch according to claim 1,
Preparing control light having a wavelength different from the signal light for switching the output path between the plurality of input / output ports via the optical switch;
The control light is multiplexed with the signal light by the optical coupler disposed at the input port, the signal light and the control light are demultiplexed by the WDM coupler disposed at the output port, and the light intensity of the demultiplexed control light A method for stabilizing the optical output of an optical switch, characterized in that: In the optical output stabilization method of the optical switch according to claim 1,
Preparing control light having a wavelength different from the signal light for switching the output path between the plurality of input / output ports via the optical switch;
The control light is combined with the signal light by the WDM coupler arranged at the input port, the signal light and the control light are demultiplexed by the WDM coupler arranged at the output port, and the light intensity of the demultiplexed control light A method for stabilizing the optical output of an optical switch, characterized in that: A plurality of optical beam output paths for an optical switch that continuously reflects a light beam input from an arbitrary input port between a plurality of input / output ports by a plurality of mirrors and outputs the light beam to an arbitrary output port. In the optical output stabilization device of the optical switch that finely adjusts the angle of the mirror so that the output light intensity becomes maximum and stabilizes the output light intensity,
Monitor the output light intensity of the output port from which the light beam is output, and control corresponding to the angular displacement of the plurality of mirrors when the output light intensity becomes maximum when the angle of the plurality of mirrors is slightly displaced The amount of control of each mirror obtained is calculated as a correction coefficient, and when the angles of the plurality of mirrors are finely adjusted, the displacement amounts of the angles of the plurality of mirrors have a predetermined relationship As described above, the light of the optical switch is provided with control means for setting a control amount for displacing the angle of another mirror in conjunction with a control amount for displacing the angle of the predetermined mirror using the correction coefficient. Output stabilization device. In the optical output stabilization device of the optical switch according to claim 5,
The control means is configured to perform update processing of the correction coefficient at a predetermined timing while interlocking controlling fine adjustment of the angles of the plurality of mirrors using the correction coefficient. Output stabilization device. In the optical output stabilization device of the optical switch according to claim 5,
A control light source that outputs control light having a wavelength different from the signal light that switches an output path between the plurality of input / output ports via the optical switch;
An optical coupler for combining the control light with the signal light is disposed at the input port,
A WDM coupler for demultiplexing the signal light and the control light at the output port;
The optical output stabilizing device for an optical switch, wherein the control means is configured to monitor the light intensity of the control light demultiplexed by the WDM coupler. In the optical output stabilization device of the optical switch according to claim 5,
A control light source that outputs control light having a wavelength different from the signal light that switches an output path between the plurality of input / output ports via the optical switch;
A WDM coupler for multiplexing the control light and the signal light at the input port;
A WDM coupler for demultiplexing the signal light and the control light at the output port;
The optical output stabilizing device for an optical switch, wherein the control means is configured to monitor the light intensity of the control light demultiplexed by the WDM coupler.

Images