Feedback type of laser diode interferometer with an optical fiber

摘要

A laser diode interferometer which uses an optical fiber is proposed. The laser diode simultaneously functions as a light source, a phase modulator, and a phase compensator. The detection of the vibration and the reduction of external disturbance are carried out, by using a feedback control for the injection current of the laser diode. So it can measure the vibration accurately in real time with a simple signal processing circuit. The optical fiber not only functions as a flexible probe, enabling us to measure the vibration of the object that cannot be moved onto the vibration absorption board, it also acts as a reference mirror, thereby simplifying the unit construction.