Patent ID: 6724967
Filing Date: 2004-04-20
Classification: G02B,Y10S

Abstract:
A method of making an optical multiplexer/demultiplexer comprising the steps of:providing a silicon wafer having a front and back face; depositing a first silica film having a first thickness on said front face td protect said front face during handling of said wafer; depositing a second silica film having a second thickness greater than said first thickness on said back face; exposing said wafer to an etchant to remove said first silica film from said front face, said etchant reducing the thickness of said second silica film to a third thickness substantially equal to said second thickness less said first thickness; depositing a third silica film forming an optical waveguide on said front face and having said third thickness; and subsequently subjecting said wafer to said high temperature anneal whereby said second and third silica films act in opposition to prevent stress-induced warping of said wafer from occurring during said high temperature anneal.