A Laser Doppler Interferometric System for Measuring Motion of Vibrating Combs

Micro-Electro-Mechanical Systems have been growing rapidly over recent years. However, measurement of their motions is a difficult problem. A laser Doppler interferometric system for measuring motion characteristics of vibrating combs in MEMS is presented. The working principle and optical diagram of the system are explained. Some key challenges in the system design are discussed. The velocity, displacement, and frequency can be acquired by demodulating the phase-modulated Doppler signal and processing the data by software.