Fringe Reduction in Laser Spectroscopy

摘要

An optical phase scrambler is coupled to a laser source to randomly modulate the optical phase. Since the optical phase is continuously changing in a random fashion, at the output of an etalon interferometer formed in the optical path, the two or more components in the interference always have certain time delay between each other, resulting in a random phase different between each other. Therefore, after interference, the fringe amplitude varies randomly as well. Then at the receiver side, the fringe noise is greatly reduced after averaging over time.

主权项

1. A method comprising:
placing an optical phase scrambler before optical fringe forming elements of an interferometer in a laser spectroscopy use; imposing continuously, by the phase scrambler, a random phase modulation onto a light beam directed to the fringe elements; detecting from light outputs of the fringe elements random optical phase difference; and averaging over time an electric signal representing a random optical phase difference of outputs from the fringe elements, the averaging enables reducing fast amplitude variation or fringe noise due to the interferometer.