A Novel Low Cost MEMS Fiber-optic Variable Attenuator for WDM Applications

This paper demonstrates a low cost MEMS variable optical attenuator (VOA) with high performance for the wavelength division multiplexed (WDM) applications. Two single-mode fibers (SMFs) are used as the input and output of VOA. A shutter is actuated into the optical path by an electrostatic comb-type actuator. The device is fabricated on a single silicon wafer by a novel simple bulk-silicon micromachining technology called the twice boron-diffusion/etching (TBDE) process. Performance measurements of the fabricated VOA show that the insertion loss (IL), the attenuation range, the return loss (RL), the wavelength dependent loss (WDL) and the polarization dependent loss (PDL) are <0.5 dB, >50 dB, <-43 dB, <0.1 dB and <0.25 dB respectively. The driving voltage is less than 30 V and the response time is less than 1 ms. As the experiment demonstrated, the fabricated MEMS VOA is suitable for the WDM applications.