A Micromechanical Optical Switch Based On Bulk Silicon Micromachining Process

The Internet, especially the World Wide Web, is dramatic examples of new modes of communication that have placed heavy demands on the current infrastructure. The current fiber communication networks will be developed to All Optical Networks in the future. And the optical-switches are the basis of the future infrastructure. The development of optical-switches has fueled an increasing interest in many research and development groups of companies and universities. Between all kinds of optical-switches, MEMS optical-switches draw attention of all over the world because they have large contrast ratio.Based on comparing all kinds of MEMS optical-switches and based on the current ability of techniques, this dissertation accomplishes the design and fabrication of the switch. And attempt to package the optical-switch with fibers.This dissertation brings forward a method to fabricate the vertical micro-mirror. We analyze the anisotropic wet etching of silicon, especially the relation between the etching speed and crystal orientation. So the mirror and mechanical part can be fabricated in a one-level mask step by bulk micromachning of (100) with KOH etching. We can on off the light path and switch the light exchange by controlling the movementof mirror.This dissertation introduces the technique of bulk micromachining, and explains the fabrication process of this optical-switch on emphases. And this dissertation analyzes some phenomena taking place in the process of switch, bring forwards the resolvents as possible as I can.This MEMS optical-switch is driven by electrostatic. So after analyzing the force of cantilever beam with a concentrated end loading, this dissertation analyzes the movement of cantilever beam driven by electrostatic force. Then get the size of beam and capacitor plate and analyze their modes using ANSYS software.Based on analyzing the loss because of scattering of thickness of vertical micro-muTor, this dissertation brings forwards the package method of using ball-lens and V grooves to align fibers.