OPTICAL WAVEGUIDE AND OPTICAL DEVICE PROVIDED WITH LONG PERIOD GRATING

摘要

PROBLEM TO BE SOLVED: To provide an optical waveguide and an optical device provided with the optical waveguide having a long period grating whose loss-wavelength characteristic is changed by physical conditions such as temperature. SOLUTION: This optical waveguide comprises plural numbers of long period gratings 2j composed of refractive index fringes 1j causing attenuation within the prescribed wavelength range about the maximum loss wavelengthλj in which the loss of a signal light beam propagating in a core 10 becomes maximum. Plural long period gratings 2j are arranged in a tarin of optical waveguides in series. In at least any one of the plural long period gratings 2j, the maximum loss wavelengthλj is shifted by the ambient conditions such as temp. or tension and the whole loss-wavelength characteristic is changed.