New technology for reduction in cost and size of silica guided-wave component

A waveguide with SiO_xN_yH_z core glass film and its fabrication method have been developed that can realise a high refractive index difference Delta to reduce the cost and size of the device. Delta can be increased by approximately 7% by controlling the nitrogen concentration. This SiO_xN_yH_z film is deposited on a quartz glass substrate with a face down type of plasma CVD method. The warp of the substrate formed by SiO_xN_yH_z core glass film is very small compared with that of conventional core glass film. The core side roughness on patterning of the core glass film in the dry-etching process is also very small. The plasma CVD method can suppress the growth of particles on the deposited film. A reduction in the cost and size of the guided-wave type component can be expected by using the SiO_xN_yH_z core glass.