TIME-DIVISION TYPE OPTICAL EXCHANGE

PURPOSE:To suppress the number of channels to a rate of linear proportion and increase channels in number easily by coupling (n-1) sets of optical delay elements which delay channel time intervals and optical switches alternately in series, and using the delay circuit to interchange light signals between optional channels. CONSTITUTION:The optical delay elements 62-1-62(n-1) which have a specific delay time and delay time-division multiplex light signals of plural channels inputted from an incidence highway 1 and 2X1 optical switches 63-63(n-2) are coupled alternately in series to constitute a serial optical delay circuit 6. Light signals of optional channels from the highway 1 are distributed by an optical distributing circuit 3 to optional switches 63-63(n-2) of the delay circuit 6. The operation timing of optical switches 63-63(n-2) of the delay circuit 6 and the circuit 3 is controlled by a control circuit 7. Then, light signals are interchanged between optional channels on the highway 1, and the number of channels for ain increase in the number of channels in a frame is suppressed to a rate of linear proportion.