Micro-opto-electro-mechanical systems

Micro-opto-electro-mechanical systems (MOEMS)

A class of microsystems that combine the functions of optical, mechanical, and electronic components in a single, very small package or assembly. MOEMS devices can vary in size from several micrometers to several millimeters. MOEMS may be thought of as an extension of micro-electro-mechanical systems (MEMS) technology by the provision of some optical functionality. This optical functionality may be in the form of moving optical surfaces such as mirrors or gratings, the integration of guided-wave optics into the device, or the incorporation of optical emitters or detectors into the system. The term may be confused with micro-opto-mechanical systems (MOMS), which more properly refers to microsystems that do not include electronic functions at the microsystem location. MOEMS is a rapidly growing area of research and commercial development with great potential to impact daily life. The basic concept is the miniaturization of combined optical, mechanical, and electronic functions into an integrated assembly, or monolithically integrated substrate, through the use of micromachining processes derived from those used by the microelectronics industry. These processes, utilizing microlithography and various etch (subtractive) or deposition (additive) steps on a planar substrate, enable the production of extremely precise shapes, structures, and patterns in various materials. See Integrated circuits, Micro-electro-mechanical systems (MEMS), Micro-opto-mechanical systems (MOMS)

The microsystems realized by these techniques can have many unique capabilities. The miniaturization that is realized is useful in itself, allowing the systems to be utilized as sensors or actuators in environments that were not previously accessible, including inside living organisms, in hand-held instruments, or in small spacecraft. The miniaturization also allows for high-speed operation of the system, as the operating speed of mechanical systems is related to their inertial and frictional properties as well as the actuating forces. Optomechanical systems have been historically constrained in this area because of the mass required for stable optical elements and the extremely precise alignment requirements of most opto-mechanical systems, which limits the forces that can be tolerated for rapid motion. In the more integrated forms of MOEMS, the systems are prealigned by the precise fabrication processes, eliminating one of the more expensive aspects of assembling conventional optical systems. The miniaturization along with the scalability of microfabrication processes allows the development of massively parallel opto-mechanical systems, with millions of moving parts, that would not be possible in conventional technologies. MOEMS can incorporate detection and drive electronics in close proximity to provide improvements in signal-to-noise ratio for sensors and simplified interfaces for actuated systems. Ultimately, these electronics may be monolithically integrated in some technologies. Because of the production volumes achievable with micromachining techniques, MOEMS are potentially much less expensive than their conventional counterparts.