Polyimide substrates, and polymer laminates for optical and electronic applications are described. Single or multi-layer waveguide structures are deposited on the polyimide substrates. Laminates including polymer or a hybrid organic/inorganic waveguiding film can be deposited on a polished polyimide substrate. The laminate can also include piezoelectric and metallic layers. Micromachined optical devices, such as cantilevered waveguide are fabricated by laser ablation using a combination of IR and UV lasers. A fiber-to-waveguide coupler with a laser-machined groove for holding the fiber is also disclosed. Holes are drilled with excimer and YAG laser in the polyimide substrate and metallized to provide continuous electrical contact between both sides of the substrate. Metallized polyimide substrates are bumped and stacked to provide high density interconnects. The polyimide substrate is bonded to a semiconductor wafer. Thin SOI or epitaxially grown layer with devices is transferred to the polyimide substrate by grinding and etching the semiconductor wafer.