Polyalkylsilyne Photodefined Thin Film Optical Waveguides.

Polysilynes, a new class of amorphous alkyl silicon network polymers, undergo a novel photooxidative crosslinking reaction, associated with an up to 15% decrease in refractive index. Both the depth and the degree of crosslinking in the film can be altered by varying the exposure wavelength, providing a means to control both the magnitude and the depth of the refractive index change. We describe the fabrication and initial measurements of waveguides formed with this index imaging technique in poly (cyclohexylsilyne) films on both oxide and poly(methyl methacrylate) coated silicon wafers. Measurements of multimode guides show typical propagation losses of 0.68 dB/cm at 633 nm. Results indicate that the polyalkylsilynes show promise as self-developing, planar optical waveguide media.