Single-mode optical waveguide using siloxane polymer on Cu-polyimide substrate

A new single mode optical waveguide has been developed to obtain optoelectronic multichip modules. It is fabricated using siloxane polymer and thin film process technology onto a copper polyimide ceramic substrate. The siloxane polymer refractive index is 1.451, very similar to that of SiO/sub 2/. It is revealed that titanium doped siloxane polymer has refractive index of 1.4537 to 1.5949 (at 632.8 nm wavelength) which can be controlled by the TiO/sub 2/ content. The siloxane polymer which contains 2.0 wt% of TiO/sub 2/ has refractive index of 1.4437 at 1550 nm wavelength. Therefore, the siloxane polymer and the TiO/sub 2/ doped siloxane polymer can be used for cladding and core layers respectively, enabling a single mode waveguide. The core size is designed to be 4-8 /spl mu/m wide by 7.0 /spl mu/m thick to obtain a single mode optical waveguide at /spl Delta/n=0.0022.