Optical switches using micromirrors in trenches and integrated optical waveguides

摘要

A planar lightwave circuit (PLC) is formed to include switching elements in which optical coupling among waveguides (34-40, 42-44, 46-48, 50-52 and 54-56; 82, 84, 86, 88, 90 and 92; 106 and 108) is determined by positions of displaceable members, such as micromirrors (62, 64, 66 and 68; 100 and 110; 116 and 118). Each switching element includes at least two light-transmitting waveguides extending along a waveguide substrate to a trench (58 and 60; 76; 102; and 120). The optical coupling between the waveguides of a switching element is dependent upon the optical characteristics exhibited at the trench. The displaceable device of a switching element has a transmitting position and a reflecting position. The displaceable device may be manipulated using microelectromechanical system (MEMS) techniques or techniques similar to those used in a dot matrix printer engine. The trench at the crosspoint of waveguides may include a liquid having a refractive index that closely matches the refractive index of the core material of the waveguides. If no index-matching liquid is included at the trench, the walls of the trench are preferably coated with an anti-reflection coating.