Laser Doppler Vibrometer Using a 45°-angled Optical Fiber for In-plane Dynamic Measurement of MEMS Actuators

A FOLDV (fiber optic laser doppler vibrometer) using a 45deg-angled optical fiber with a self-aligned micro lens can be used to measure the in-plane dynamic motion of microstructure that does not allow optical access in sidewall direction. This system features a good immunity to external disturbance and easy alignment of optical components during system assembly. The performance of the proposed fiber-based vibrometer is evaluated in terms of signal stability, and compared with other type of LDV.