HIGH REFRACTIVE-INDEX DIFFERENCE AND LOW-LOSS OPTICAL WAVE-GUIDE FABRICATED BY LOW-TEMPERATURE PROCESSES

A singlemode optical waveguide has been developed with a high refractive index difference DELTA of 2% and low loss of 0.12 dB/cm at 1.3 mum wavelength. This waveguide consists of buffer layer, core ridge, and cladding layer of SiO(x)N(y)H(z) formed by the plasma CVD method at a low temperature of 270-degrees-C. The absorption loss which is affected by the OH ion content at 1.39 mum wavelength can be decreased by annealing at 500-degrees-C under N2 atmosphere. The fabrication process at low temperature is effectively used for the monolithic integration of photonic/electronic circuits.