PURPOSE: To provide the waveguide type optical switch having a high extinction ratio in a wide wavelength region for switching optical transmission paths and a high yield of production.
CONSTITUTION: Optical switching circuits 22, 23, 24 of Mach-Zehnder interferometer type constitution of two-inputs and two-outputs are cascade connected in two stages and are formed on a substrate 21. The wavelength at which the optical coupling rate of the optical switching circuit 22 of a first stage of the Mach-Zehnder interferometer type constitution attains 100% is set at 1.52μm and the wavelength at which the optical coupling rate of the optical switching circuits 23, 24 of a second stage of the Mach-Zehnder interferometer type constitution attains 100% is set at 1.58μm, by which the waveguide type optical switch of a wavelength band of 1.55 wavelength is constituted. The outputs are switched by the operation and non-operation of all of phase shifters 22c, 23c, 24c. Output ports 2a, 2c are used when an input port 1a is used and output ports 2b, 2d are used when an input port 1b is used.
MORINAKA AKIRA
KITO TSUTOMU
