Santec started developing optical components using MEMS (Micro-Electro-Mechanical Systems) technology in 2002. The first product was a Variable Optical Attenuator (VOA) that is now widely used in telecommunications systems. The initial design was realized with close collaboration with the Fujita-Toshiyoshi Laboratory at the University of Tokyo. Prototypes were made in the university laboratories and the technology was then transferred by Santec to a MEMS foundry for mass production.
What’s MEMS ?
MEMS devices are very small mechanical components that are operated by electronics. They contain moving parts which are typically between 1 and 100 micrometers in size. A variety of materials can be used but most commonly the devices are made from silicon. This is patterned and etched using similar technology to that developed for the microelectronics industry. In contrast to conventional machining processes, such as drilling and milling, the highly accurate semiconductor process can produce reliable devices, in large volumes at very low cost.
MEMS technology was originally developed in the late 1980’s and can be found in a wide range of commonly used products. MEMS is widely used in flow sensors and for the accelerometers used in car airbags and TV games that detect our motion. Miniature microphones used in PCs and mobile phones are also made using MEMS.
Adjustment of optical power is one of the basic functions required in a modern telecommunications system. It can be likened to changing a resistance in an electrical circuit. This function has traditionally been achieved using a mechanical component called a Variable Optical Attenuator (VOA). Santec has used MEMS to create a mirror that tilts when an electrical voltage is applied. The degree of tilt determines the amount of light transmitted by the component. Santec’s unique design, using an asymmetrically driven parallel plate tilt-mirror created a component with a simple design that is extremely stable and reliable in operation. This design has been mass produced and has been installed by our customers in telecommunication systems all over the world.
Recently, we have also been applying our MEMS technology to create components for medical imaging applications. Fig.3 shows the design of our endoscope probe that uses a MEMS scanning mirror to scan a laser beam and capture an image. Combined with Santec’s OCT technology this device is being applied to gastrointestinal and urological imaging as an alternative to biopsies in the detection of cancer and other diseases.