Study On Key Technologies Of MEMS Optical Switch For Optical Communication

All optical network (AON) is a preferred way of new generation wideband network and optical switch is the key technology for AON. Among various schemes of optical switches, MEMS optical switch is the competitiveness one. Study on the key structure and characteristic of MEMS optical switches has important theoretic meaning, applied value and marketable foreground. This dissertation discusses the core technologies of 2D MEMS optical switch. By using bulk and surface micromaching process, a novel micromirror with its driving structure is made with new structure material. The main researches points in the dissertation are as followings:The basic technology and methods for MEMS process is researched to serve as the theoretic basis for design of MEMS devices. After theory and simulation analysis on the schemes of micromirror and driving structures, which are the core technologies of MEMS optical switch, a static electricity driving horizontal torsion mirror optical switch has been selected as the mean research point. The sizes and process design of a static electricity driving horizontal torsion mirror optical switch has been done to make a prototype. Bulk micromaching experiments have been down to find a new TMAH wet deep etching process. A set of process parameters are pointed out to ensure that the TMAH wet deep etching can have smooth etched surface. The novel MEMS bulk maching process is compatible with IC process. Experiments on residual stress of poly-silicon micromirror have been done to know the effect of stress on the characteristics of micromirror. A conclusion has been made that residual stress control of poly-silicon micromirror is very important to make a useful poly-silicon micromirror. A novel Ni-Cr-Au micro-structure scheme is brought forward after research on the silicon-based non-silicon optical switch. By theoretic and experimental analysis, a Ni-Cr-Au optical switch unit is fabricated successfully. Measuring experiments have been done on the Ni-Cr-Au micromirror for electrostatic driving torsion mirror optical switch. The measurements items include the roughness of the micromirror, the reflectivity spectral curve, the driving experiments and cycle experiment. The result shows that the mirror has good reflective performance. And driven by static electricity, it can rotate more than 15 degrees at voltage less than 15V. This kind of novel mirror will have good potential applications for MEMS optical switches.According to the measurement results, the electrode has been improved and a tilt electrode scheme has been researched theoretic. The theoretic analysis shows that tilt electrode help to reduce the driving voltage and improved the stability and reliability of optical switch.The main creative points in the dissertation are as followings:1,A process of TMAH wet etching is brought forward to replace DRIE and a set of very important parameters for TMAH etching is achieved to ensure that TMAH etching can have smooth surface. 2,A novel Ni-Cr-Au micromirror for optical switch has been researched. The Ni-Cr-Au micromirror unit has been fabricated. The measuring result shows that the mirror has good optical performance, stable mechanical property and can achieve optical switch function. This dissertation shows that Ni-Cr-Au micromirror for optical switch has good optical performance, stable mechanical property and can achieve optical switch function. The novel optical switch scheme has very important meaning for the research and practicalization of 2D MEMS optical switch.