Study On MEMS Optical Switch Based On Vertical Torsional Micromirror

In this thesis, a novel 1x2 optical switch was proposed, which is based on a vertical torsional micromirror. Micromirror was fabricated with (110)-oriented silicon wafer by wet etching technology. Micro actuator was composed of a cantilever and variable-gap electrodes. The optical coupling was carried out by adding a pair of ball lens between fibers. The optical switch devices were designed and made.The loss of MEMS optical switch using direct fiber coupling is big. However the optical loss can be reduced after the optical beam is collimated. In the thesis, ball lenses were added just to collimate the beam. The influenced factors were analysed in detail. The reflected film with high coefficient was a part of micromirrors. The reflected characteristics was calculated on metal materials to find out that aluminum and gold are the best choices. Their saturated reflectivity is up to 97% and the thickness is about 200nm. In the range of moderate incident angles, the difference dependent on polarization is little.Angle deflection is an effective operation on optics, which is widely used in optical switch and variable optical attenuator. In order to lower the driving voltage of a fixed-gas capacitor, the edge of electrodes were designed and fabricated with curves. The DC voltage and frequency responds were simulated. Based on the calculations, the actuator and fixing spring were designed. The actuator was used to steer the optical beam and the spring was used to fix the fiberA vertical micromirror with high surface quality was wet etched on (110)-oriented silicon wafer, which was of significance in optical devices. The actuator was fabricated mainly by deep reactive ion etching technology. The pull-in voltages of the actuator were tested about 69V and 73V, respectively, which were well agreed with the simulated results.The loss of the developed optical switch was tested about 4-5dB, and the crosstalk was about 45dB. The results show that the optical device can perform the function.As one part of the achievements "Micro-Opto-Electro-Mechanical Systems (MOEMS) key technologies for optical communication applications", the work was awarded with "Shanghai municipal prize for scientific and technology progress in 2003, second prize"...