Optical Micro-Electro-Mechanical Systems for Add/Drop Multiplexing and Infrared Spectroscopy

摘要

Wide ranging efforts in development of various Micro-Electro-Mechanical (MEM)devices over the past twenty years have created a vast collection of novel devicesthat can be fabricated in numerous ways. As the MEMS field matures it is importantto remember the systems aspect the name implies and ensure useful andcomplete systems are constructed utilizing these wonderful devices. This thesisfocuses on two different areas of application for optical MEM systems.The first is a system for optical telecommunications networks that enables anoptical add/drop multiplexer, also frequently called a wavelength selective switch.Wavelength selective switches anticipate the need for inexpensive optical switchingcomponents with the extension of the optical domain of telecommunications tothe end user through fiber to the home. The wavelength selective switch studiedis based on the hybridization of a MEMS based optical switch with a particulartype of planar lightwave circuit, or on-chip waveguiding device, called an ArrayedWaveguide Grating (AWG). Three separate MEMS switches were implementedinto this type of system: a lateral fiber actuator, a scanning micro-mirror, and abinary micro-mirror array. The binary micro-mirror array displayed the greatestperformance and is additionally advantageous because of the possibility of furtherintegration. This implementation of a wavelength selective switch provides excellentoptical networking properties and performance at low power and with a smalldevice area compared to other switch implementations. Additionally, the systemis scalable as the network increases in port count and channel density.The second system studied is an optical gas spectrometer. A scanning MEMSmirror was used with various additional optical components to create a Non-Dispersive Infra-Red (NDIR) gas detector. The MEMS mirror is used in conjunctionwith a Linear Variable Filter (LVF) to scan a particular range of IR radiation.By detecting the transmission spectrum within the IR radiation band, detectionof gases based on their unique radiation absorption pattern can be carried out.Detection of CO2 in concentration ranges from 400ppm to a few percent was performed.Simultaneous detection of multiple species is possible. The system offersa potentially portable and inexpensive gas spectrometer with accuracy necessaryfor various commercial needs.