12 Optical MEMS

In 1989, a group of scientists and engineers in Salt Lake City started a workshop called Micro-Tele-Operated Robotics Workshop. There, the acronym for Microelectromechanical systems (MEMS) was officially adopted. However, MEMS technology has already had a head start since at least 7 years ago from the classic work published by Petersen in 1982 [1]. Twenty years later, MEMS technology has started major novel innovations in several scientific fields and created highly promising market potential. In 2003, the most conservative market studies predict a world MEMS market in excess of $8 billion. Optics and photonics are among these research fields impacted by MEMS techniques. Optical MEMS has created a new fabrication paradigm for optical devices and systems. These micro optical devices and systems are inherently suited for cost effective wafer scale manufacturing as the processes are derived from the semiconductor industry. The ability to steer or direct light is one of the key requirements in optical MEMS. In the past two decades since Petersen published his silicon scanner [1], the field of optical MEMS has experienced explosive growth [2,3]. In the 80’s and early 90’s, displays were the main driving force for the development of micromirror arrays. Portable digital displays are commonplaces and head mount displays are now commercially available. In the past decade, telecommunications have become the market driver for Optical MEMS. The demand for routing internet traffic through fiber optic networks pushes the development of both digital and scanning micromirror systems for large port-count all-optical switches with the ability to directly manipulate an optical signal, Optical MEMS systems eliminate unnecessary optical-electrical-optical (O-E-O) conversions. In the biomedical arena, micro-optical scanners promise low-cost endoscopic three-dimensional imaging systems for in vivo diagnostics. This chapter summarizes the state of the art of Optical MEMS technology by describing basic fabrication processes to derive with actuation mechanisms and select examples of devices that are either commercially available, or show great promise of becoming products in the near term. The chapter is organized into the following sections: Section 2 describes the generic actuation mechanisms commonly used for MEMS devices. Section 3 discusses the applications.