| 摘要 |
PURPOSE:To cancel the dispersion of optical fibers without transforming an optical signal into an electric signal. CONSTITUTION:Directional couplers 6, 7, 8, and 9 each of which has two input ports different in length and two output ports different in length have longer ports mutually cascaded in many stages and have shorter ports mutually cascaded in many stages, and a directional coupler 5 which has two output ports having the same length is connected in the preceding stage, and a directional coupler 10 which has two input ports having the same length is connected in the succeeding stage, thus constituting a multistage asymmetrical Mach-Zehnder interferometer. The number of stages of cascading of directional couplers 6, 7, 8, and 9 each of which has two input ports different in length and has two output ports different in length is set to a multiple of 4 or (a multiple or 4)-1. |
