Variable optical attenuators (VOAs) are used everywhere in the wavelength-division-multiplex (WDM) fiber optic network. VOAs are used to adjust the optical intensity of each wavelength component traveling in a single optical fiber such that signal pulse shape woud not suffer from fiber's dispersion.
By using the MEMS technology, we have developed a very reliable VOA in collaboration with a fiber optic component company Santec Co., Japan. The VOA is made of an SOI wafer with double-side DRIE processes. The mirror in the middle is 0.6 mm in diameter and suspended with a pair of torsional hinges. There is a shaped cut on the backside of the mirror part and is used as a counter electrode for electrostatic operation. Typical driving voltage is 5 to 12 V for optical attenuation level of as large as 40 dB. The VOA can survive mechanical shock of 500 G or higher, and has mechanical tolerance of up to 50 G without causing optical intensity fluctuation of +/- 1 dB.
Chunichi Sangyo Gijutsu Sho 2004 was awarded to this work [#p4964b8b]