Patent ID: 6134372
Filing Date: 2000-10-17
Classification: G02F

Abstract:
A light intensity attenuator comprising:light input means for extracting a transmitted optical signal, said light input means comprising an optical fiber which is optically connected to an input end of an optical waveguide;light-intensity attenuating means for receiving via the light input means the transmitted optical signal which includes a pulse-shaped surge component, and attenuating the light intensity of the surge component by a desired amount and then outputting the optical signal, wherein said light-intensity attenuating means comprises a substrate and an optical waveguide formed on the substrate, at least one of the substrate and the optical waveguide being made of a material producing a non-linear optical effect, and the refractive index of the optical waveguide with respect to the optical signal is smaller than the refractive index of the substrate with respect to a higher harmonic of the optical signal;light output means for returning the output from the light-intensity attenuating means, wherein the light output means is an optical fiber which is optically connected to the output end of the optical waveguide; anda part of the optical signal input into the optical waveguide is wavelength converted by the non-linear optical effect into a light portion having a wavelength shorter than that of the optical signal, this wavelength-converted light portion is scattered and radiated from the optical waveguide over a neighboring area of the substrate, and the remaining portion of the optical signal is output from the output end of the optical waveguide into the output optical fiber.