Noncontact vibration sensors based on current modulated external cavity semiconductor lasers

An improvement in performance and design of noncontact vibration sensors ba sed on external cavity semiconductor lasers is demonstrated. A technique fo r narrowing RF spectral peaks in external cavity lasers with moderate optic al feedback by direct current modulation is explained. Current modulation f requencies suitable for use with developed position and vibration sensors a re identified. Improvements in accuracy and resolution for the sensors are recorded and illustrated.