Abstract

Wavelength-division multiplexing (WDM) is promising for increasing the transmission bandwidth and the routing capability of optical communications.¹ However, the implementation of practical systems has been limited by device technology.^2,3 An ideal device would have a wide and continuous tuning range, low control power, low insertion loss, simple coupling, high extinction ratio, reasonable tuning speeds, no polarization dependance, compatibility with multi-mode fibers, and simple fabrication to facilitate 2-D arrays. Although many tunable filter structures have been presented, none has met all the above criteria. We present a micromechanical surface-normal transmission filter that may be continuously tuned over 70 nm with a control voltage of 5 V and a power dissipation of as little as 250 pW. The surface-normal structure is naturally fabricated as a 2-D array and is optimal for fiber coupling. The device-fabrication process is simple and high yield, requiring only two noncritical lithography steps. In this work, we report detailed measurements to show that the device is polarization insensitive and has a resonance frequency of 1.1 MHz.

© 1995 Optical Society of America