| 摘要 |
PURPOSE:To reduce the crosstalk of the Mach-Zehnder type optical switch. CONSTITUTION:The optical switch SW 1 is in a cross state unless currents flow to heaters H1 and H2, and a light signal S1 which is inputted from, for example, an input port Pi 1 passes through arms A1 and A2 and is outputted from an output Po 2. At this time, the effective optical path length of the arm A1 (or A2) is adjusted by supplying a current from an optical path length fine adjusting circuit 12 to the heater H1 (or H2) so that the effective optical path difference between the arms A1 and A2 is an integral multiple of the wavelength of the light signal S1. On the other hand, a state change circuit 11 supplies a current to the heater H1 (or H2) and the effective optical path difference between the arms A1 and A2 is accurately equalized to an integral multiple of signal light wavelength plus a half wavelength, so that the optical switch enters a bar state. In this bar state, the light signal S1 which is inputted from, for example, the input port Pi 1 is outputted from the output port Po 1. |
