A new micromechanism for transformation of small displacements to large rotations for a VOA

New movement translation micromechanism (MTM) is proposed to transfer and amplify small in-plane displacement or movement into large out-of-plane vertical displacement or rotation. Based on this MTM, we may just apply 3-V dc load to generate 3.1-μm in-plane movement, then 26.4° rotation angle of pop-up micromirror can be subsequently derived. An axial aligned fiber-to-fiber variable optical attenuator (VOA) device using the MTM, a U-shaped electrothermal actuator array, and the pop-up micromirror to reflect the attenuated light toward out-of-plane direction is designed and characterized. The proposed new VOA device achieves 37-dB attenuation range under 3-V dc load, while return loss, polarization-dependent loss, and wavelength-dependent loss at attenuation of 3 dB are measured as -45B, 0.05, and 0.28 dB. This new concept of steering a portion of input light toward out-of-plane direction is proven to be feasible for VOA applications.