A bulk-micromachined corner cube retroreflector with piezoelectric micro-cantilevers

Jae Park,Jongcheol Park

doi:10.1186/2213-9621-1-7

Abstract

A piezoelectrically actuated corner cube retroreflector (CCR) has been investigated for free space optical communications. The proposed CCR consisted of two mutually orthogonal bulk-micromachined mirror assembled with piezoelectrically actuated horizontal mirror. The vertical mirrors were fabricated by using anisotropic wet-etching of double silicon-on-insulator (SOI) wafer and horizontal mirror was supported by two stress-compensating and one actuating lead zirconate titanate (PZT) micro-cantilevers. The fabricated CCRs exhibited angular displacement of 1.87° at 5 volts and switching times of 276 µ s. It also exhibited a good cut-off frequency of 2.5 kHz which can be digitally modulated up to about 5 kb/s.

Highlights

A corner cube retroreflector (CCR) has been developed as an optical passive transmitter in wireless optical communication with low power consumption [1]
The PZT micro-cantilever was utilized as an actuator for the horizontal mirror to obtain large angular displacement
Since there is difficulty in the control of the residual stress in the deposition of PZT thin film, it might be serious problem for the MEMS CCR because the colinear differential scattering cross section (CDSCS) of MEMS CCR is affected by the radius of curvature and angular misalignment of mirrors [5]

Summary

Introduction

A corner cube retroreflector (CCR) has been developed as an optical passive transmitter in wireless optical communication with low power consumption [1]. While they have presented good feasibility, it is not easy to obtain the accurate angular alignment to form mutually orthogonal mirror surfaces. For achieving good surface roughness, accurate angular alignment, and mass productivity of the vertical mirror, a new fabrication process was developed using a double-SOI wafer and anisotropic KOH etching technique.

Results

Conclusion