Patent ID: 6434286
Filing Date: 2002-08-13
Classification: H04Q

Abstract:
An optical switching apparatus comprising:a first optical transmitter that converts an electric signal to be transmitted to an optical signal; a first variable (coupling ratio) optical coupler having first and second input ports and first and second output ports, in which the optical signal outputted from said first optical transmitter is inputted to the first or second input port, and said first variable (coupling ratio) optical coupler outputs the optical signal inputted to the first or second input port, to the first and second output ports connected respectively to first and second optical transmission lines corresponding respectively to working and protection systems, at a first coupling ratio set by a first drive signal; a second variable (coupling ratio) optical coupler having third and fourth input ports and third and fourth output ports, in which the optical signal transmitted through the first and second optical transmission lines is inputted respectively to the third and fourth input ports, and the second variable (coupling ratio) optical coupler outputs the optical signal inputted to the third and fourth input ports, to the third and fourth output ports at a second coupling ratio set by a second drive signal; a first optical receiver that converts the optical signal received from the third output port of said second optical coupler, to an electrical signal; a first performance monitor that monitors performance of the electric signal received by said first optical receiver; a system controller that outputs instruction signals for switching or connecting said first and second optical transmission lines from the working system to the protection system or inversely, when degradation or interruption of the received signal is detected based on the performance detected by said first performance monitor; control circuits that output first and second control signals for controlling the first and second coupling ratios of said first and second optical couplers, based on the instruction signals received from said system controller, respectively; and drive circuits that output the first and second drive signals for instructing the first and second coupling ratios of said first and second optical couplers based on the first and second control signals received from said control circuits, respectively.