| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical CDMA circuit, that conducts spread modulation and inverse spread demodulation for an optical signal with high S/N in an optical spread spectrum communication system not by summing power but by summing electric field strength so as to attain substantial subtraction. SOLUTION: A circuit is made up of an input optical waveguide 1, branching N channel array gratings 2, 3, 4, N sets of 2×2 optical switches 5, synthesis use N channel array gratings 12, 13, 14, and an output optical waveguide 15, the branching array grating and the synthesis array grating are tied by N-sets of optical waveguide paths 10, 11 each consisting of N lines with equal length, and the 2×2 optical switches 5 and phase shifters 6, 7 are placed to part of each optical waveguide. Thus, summing of electric field strength is attained. Moreover, any input port and any output port among two input, ports 8 and two output ports 9 of the N sets of 2×2 optical switches 6 are used for monitor pots of the 2×2 optical switches 5. |
