Understanding Smart Sensors - Nomads.usp

MEMS Beyond Sensors 2139.3.2 MicroopticsA number of microoptical devices have been produced by micromachiningtechniques, including gratings, lenses, air bridges, electrical interconnects,fiber-optic couplers, alignment aids, corner reflectors, and waveguides [17]. Inaddition to silicon, a number of III-V semiconductor materials are being investigatedfor improved optical performance. A chemically assisted ion beam etching(CAIBE) process using argon and xenon ion beams and chlorine as thereactive gas was used to fabricate surface-emitting lasers. The 3-mm diameterlasers operated at room temperature with a threshold current below 1.5 mA anda differential quantum efficiency of 16%. However, a number of problemsmust be solved for the lasers to provide a viable solution for optical computing,chip-to-chip communications, and optical switching. The combination ofmechanics, optics, and electronics at the micron scale promises to be an importantfield in optical microsystems.A different combination of micromachining and optics is demonstratedin Figure 9.10 [18]. The polysilicon microscanner in the figure consists of aFigure 9.10 A rotating polygon optical microscanner made by electroless plating of nickel.(Courtesy of Case Western Reserve University.)