High refractive index difference and low loss optical waveguide fabricated by low temperature processes

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