Low loss optical waveguide device

Abstract

A method for forming optical devices on-planar substrates, as well as optical devices formed by the method are described. The method uses a linear injection APCVD process to form optical waveguide devices on planar substrates. The method is performed at approximately atmospheric pressure. According to the method, a wafer with a lower cladding layer already formed by either CVD or oxidation is placed on a conveyer, which may include a heating element. The heated wafer is transported underneath a linear injector such that the chemicals from the linear injector react on the wafer surface to form a core layer. After the core layer is formed, photoresist is spun on the surface of the wafer, and then standard lithography is used to pattern the optical devices. Next, reactive ion etching (RIE) is used to form waveguide lines. The remaining photoresist is then removed. An upper cladding layer is formed to substantially cover the core regions. The upper cladding layer may be formed in a manner similar to that used to form the core layer. The refractive index of the upper cladding layer is generally the same as that of the lower cladding layer. The refractive index of the core layer is generally 0.2% to 2% greater than that of the upper and lower cladding layers.