Optical amplification and photosensitivity in sol-gel based waveguides

The sol-gel process has emerged as an effective route for the fabrication of optical waveguides and guided wave devices and circuits. In particular, it is possible to incorporate active dopants like neodymium, erbium, and cesium for integrated optical active devices and circuits. A review of recent research on active devices and circuits based on sol-gel process is made. Specific studies undertaken in our laboratory on optical amplification and photosensitivity characteristics of sol-gel optical films are presented. In the case of modeling and analysis of active sol-gel films for the study of optical amplifiers, we present the atomic susceptibility theory of lasers and also the method of rate equations, duly taking into account the waveguide parameters. The beam propagation method is applied to study the propagation and gain characteristics of actively doped sol-gel film devices such as straight waveguide, Y-branch, and directional coupler. Formation of Bragg gratings in cerium-doped films are investigated. Also, futuristic applications in MEMS where the sol-gel process will be effectively used to form optical layers that can be controlled by mechanical effects are pointed out.