OPTICAL INPUT/OUTPUT SWITCH

摘要

PROBLEM TO BE SOLVED: To obtain an optical input/output switch which lessens light loss and is simple by providing the switch with a double refractive material and an etalon element which is capable of controlling a resonance wavelength by an external electric field and outputs light having the wavelength meeting the resonance wavelength. SOLUTION: The liquid crystal etalon element 30 using liquid crystals as the double refractive material 38 enables the wavelength selection by regulating the double refraction of the liquid crystals with the voltage to be applied to ITO films 34A and 34B, thereby controlling the resonance wavelength. The DROPL light signal of a desired specific wavelength may be taken out at a terminal T3 by the voltage applied on the etalon element 30. The signal exclusive of the selected wavelength is reflected by the etalon element 30, is outputted from a terminal T2 and is transferred to another node. The ADD light signal of a specific wavelength may be outputted to a terminal T2 from the transmitted light signal from the self-node made incident from a terminal T4 by applying the voltage meeting the output wavelength to the etalon element 30.