Abstract: An optical one-to-one protection switching apparatus exchanges signals between a transmit node and a receive node. If a fault is detected in the first transmission line (down-stream), a controller in the node controls a drive circuit so as to shut off a gate. Then, the controller in the transmit node upon receiving a switching request from the receive node, controls the drive circuit so as to shut off the gate. Thereby, the optical switch is switched. The transmitter of the client terminal is thus connected to the second transmission line (down-stream). Upon receiving the switching request from the transmit node, the optical switch in the receive node is switched. Thereby the receiver in the client terminal is connected to the second transmission line (down-stream).

Abstract: Variable (coupling ratio) optical couplers 3-0 and 6-0 each have ports of two inputs and two outputs, and the coupling ratio of inputted light is variably controlled by drive circuits 4-1 and 7-1. In the optical 1+1 switching structure, the coupling ratio of the variable (coupling ratio) optical coupler 3-0 is controlled to be 50%:50%. The variable (coupling ratio) optical coupler 6-0 is controlled to have the coupling ratio of 100%:0% or 0%:100%. In the optical 1:1 switching structure, the coupling ratios of the variable (coupling ratio) optical couplers 3-0 and 6-0 are controlled to be 100%:0% or 0%:100%. When a performance monitor (0) 9-0 detects signal degradation, signal interruption, and the like, the system controller 1-0 sends an instruction signal and the control circuits 20-0 and 21-0 output control signals for controlling coupling ratios of the variable (coupling ratio) optical couplers 3-0 and 6-0, respectively.

Abstract: An optical signal switching apparatus that maintains an optical switch to a specified state even when noise is generated during the turning on and/or off of power to an optical switch control unit which controls the optical switch. The optical switch control unit includes an optical switch driving unit, a power supply and a power supply surveillance unit. When a specified condition of the power supply is not satisfied, a control signal is generated by the power supply surveillance unit. Upon detection of the control signal the optical switch driving unit, fixes the state of the optical switch to a previously set state without regard to the input to the optical switch driving unit.

Abstract: Variable (coupling ratio) optical couplers 3-0 and 6-0 each have ports of two inputs and two outputs, and the coupling ratio of inputted light is variably controlled by drive circuits 4-1 and 7-1. In the optical 1+1 switching structure, the coupling ratio of the variable (coupling ratio) optical coupler 3-0 is controlled to be 50%:50%. The variable (coupling ratio) optical coupler 6-0 is controlled to have the coupling ratio of 100%:0% or 0%:100%. In the optical 1:1 switching structure, the coupling ratios of the variable (coupling ratio) optical couplers 3-0 and 6-0 are controlled to be 100%:0% or 0%:100%. When a performance monitor (0) 9-0 detects signal degradation, signal interruption, and the like, the system controller 1-0 sends an instruction signal and the control circuits 20-0 and 21-0 output control signals for controlling coupling ratios of the variable (coupling ratio) optical couplers 3-0 and 6-0, respectively.

Abstract: Upon receiving a check request 300 from a management system 250, a controller 230 sends a switching request 310 to an optical switch driver 165. The optical switch driver 165 sends a drive signal 320, and an optical switch 160 switches from a first transmission line 120 to a second transmission line 130. A receive signal performance monitor 190 sends a sensing result 330 for the second transmission line 130 to the controller 230. The controller 230 sends a switch-back request 340, and the optical switch 160 switches from the second transmission line 130 to the first transmission line 120. Based on information from the receive signal performance monitor 190, a first transmission line optical sensor 210, and a second transmission line optical sensor 220, the controller 230 performs a sensing result save 360 in a memory 240. A management system 250 saves a results report 400 from the controller 230 in a memory device.

Abstract: An optical signal switching apparatus that maintains an optical switch to a specified state even when noise is generated during the turning on and/or off of power to an optical switch control unit which controls the optical switch. The optical switch control unit includes an optical switch driving unit, a power supply and a power supply surveillance unit. When a specified condition of the power supply is not satisfied, a control signal is generated by the power supply surveillance unit. Upon detection of the control signal the optical switch driving unit, fixes the state of the optical switch to a previously set state without regard to the input to the optical switch driving unit.