PECVD GROWN MULTIPLE CORE PLANAR WAVE-GUIDES WITH EXTREMELY LOW INTERFACE REFLECTIONS AND LOSSES

A novel and generic method for fabricating silica-on-silicon planar li ghtwave circuits with cores composed of two or more different types of glasses is described. The basic process technologies used are silane/ germane/nitrous-oxide based plasma enhanced chemical vapor deposition and fluorine based reactive ion etching. Very high-quality interfaces between the different core glasses are obtained with interface losses as low as 0.022 +/- 0.012 dB and reflection levels below -80 dB. This technique adds flexibility and ease to the design of complex silica pl anar waveguide components, allowing, e.g., independent optimization of amplifying and passive sections in lossless devices based on erbium-d oped planar waveguides.