Fabrication of Er Doped Glass Films as Used in Planar Optical Waveguides

Abstract

AbstractSilica integrated optical circuits are expanding in functionality to include optically active waveguides. Traditionally, the planar optical waveguide structures include silica based glass films such as thermal oxides, phosphorous, and boron-phosphorous doped glasses. Various efforts have successfully doped conventional waveguides with Er, typically by solution doping. Material issues such as rare earth solubility and glass structure dictate that efficient optical amplifiers based on such waveguides have path lengths in excess of 10–15 cm. We have developed an alternative strategy using Er-doped soda-lime silicate glass films on silicon. The waveguide processing utilizes methods of deposition similar to those used in silicon IC technology, with modificatons in the compositions and thicknesses. In these glasses the effective solubility limits are relaxed and we have successfully fabricated short path length devices which demonstrate net gain of more than 4 dB/cm. Short path length devices offer a potential advantage in highly integrated multi-channel devices and offer an additional building block in system architectures.