| In the investigation reported here a micro-cantilever optical-MEMS sensor based on the AlGaAs material system is designed, modeled and fabricated. The idea is to design micro beams consisting of dielectric waveguides for single mode propagation at 785 rim or longer wavelengths. These beams when cleaved to form waveguide cantilevers can have numerous interesting applications. For instance, if light is coupled into the device and it is externally driven with a piezo chip, the misalignment of the beams at resonance would cause coupling loss from one beam to the other. This would result in a change in the transmission power measured at the output beam. This effect can be utilized for vibration sensing, or simply optical modulation.; As part of developing the fabrication process, a dry/wet etch technique is demonstrated to form AlGaAs micro beams using the Br-IBAE dry etcher, and a peroxide/alkaline solution. The recipe for the fabrication process is reported here along with some light coupling and wave guiding tests conducted on some initial samples.; The finite element method (FEM) (COMSOL package) is employed here to first model the design parameters, and then simulate the actual optical misalignment phenomenon. The misalignment phenomenon is simulated by coupling the structural mechanics module to the electromagnetics module using the moving mesh Arbitrary Langrangian Eulerian (ALE) method to predict the optical coupling efficiency change as a function of the loading force. The simulated results have been used to design the micro-cantilever beams on the actual device. |
