Optical Processing Employing a Novel Optical Transistor

We propose to develop and demonstrate the feasibility of an all optical switch / transistor capable of filling multiple applications roles. As speeds in communications, sensing, and computation increase rapidly, faster and faster switching mechanisms areessential. Since optical signal processing has distinct advantages, optical switching techniques have received much attention for addressing these applications. Because of the complexity of optical switching mechanisms, often one must trade off one ormore of the five basic parameters: rejection efficiency, actuation power, cost, speed, and size. We propose a novel approach for optical switching that can optimize all five parameters simultaneously. Even though there are many other optical switchdesigns, such as electrostatically driven flip-up micro-mirrors, our approach is unique for being an all-optical device. We have observed an opto-mechanical phenomenon that could have tremendous importance in optical processing. This switching mechanismis a micro-mechanical movement induced by the optical absorption by a released single crystal waveguide material. Photons above the bandgap are absorbed in the semiconducting material, which generate electron-hole pairs. If enough electron-hole pairs arecreated and recombination is slow, the lattice parameter of the material changes, resulting in material strain. If the waveguide material is free to move (such as a severed micro-bridge), then the strain will alter the position of the waveguide material.This micro-mechanical movement can be used to rapidly switch a light beam traveling down the waveguide either as a modulator (on / off), or to redirect light coming from the end of the waveguide onto two or more different receiving channels (switch)through efficient evanescent wave coupling. This switching mechanism coupled with a micro optical amplifier would truly be analogous to an electronic transistor.Commercial employment of optical signal processing / routing has distinct advantages overconventional technology. Optical switches / transistors have received much attention recently for addressing numerous applications in optical computing, fiber optic telecommunications, and sensing. Since this is an optically actuated optical switch /transistor, ultra-high resonant frequency silicon / diamond MEMS waveguides can also be actuated. With this development we may finally realize the full advantages of photons over electrons due to the use of two-way conductors, cross conductors, ultra-highbandwidth and simultaneous multi-wavelength operation.