THIN FILM OPTICAL FILTER, MANUFACTURE THEREFOR, AND OPTICAL RECEIVING MODULE USING THIN FILM OPTICAL FILTER

摘要

PROBLEM TO BE SOLVED: To reduce the thickness of a filter, and vary the transmission wavelength by adjusting the position of the filter by providing a multilayer film structure having a film thickness distribution in which thin films formed of dielectric different in refractive index are stacked on a thin film substrate. ;SOLUTION: Polyimide is applied onto an InP temporary substrate and formed into a polyimide film 1 by raising the temperature, and subsequently, Ta2O5 film 2 and SiO2 film 3 are sequentially laminated on the polyimide film 1 by electron beam deposition. Polyimide is applied onto the uppermost SiO2 film 3, a flat plate is made closely adhere to the surface thereof at an angle, and pressurized while the temperature is raised to form a polyimide layer 4 having film thickness distribution. Further, after the flat plate is separated, SiO2 film 3 and Ta2O5 film 2 are again alternately laminated by electron beam evaporation on the polyimide layer 4. Lastly, the obtained multilayer film is cut and InP temporary substrate is removed by etching to obtain a thin film optical filter having a film thickness distribution.;COPYRIGHT: (C)2000,JPO