Process for making light waveguide element

摘要

A light waveguide element is made by forming only an upper clad layer ( 40 ) and a core layer ( 32 ) without etching an optical axis height-adjusting sections. By using plasma chemical vapor deposition (CVD) which is good at controlling the film thickness, it is possible to provide without difficulty a light waveguide element with a height-adjusting section that has a precise film thickness, making it possible to provide precise optical axis vertical alignment upon mounting. By forming alignment markers in the same photolithography as that of the core formation, it is possible to provide precise horizontal optical axis alignment.