ULTRA-LOW FREQUENCY-NOISE SEMICONDUCTOR LASER WITH ELECTRONIC FREQUENCY FEEDBACK CONTROL AND HOMODYNE OPTICAL PHASE DEMODULATION

摘要

The present invention provides a semiconductor laser that operates with a frequency feedback control loop for frequency-noise reduction. The frequency-reduction architecture utilizes a homodyne optical phase demodulation approach. Such phase demodulation can be implemented with help of an unbalanced Michelson interferometer with fiber optics delay and symmetrical 'n x n' optical coupler. The entire demodulator is packaged in a small form-factor package which doesn't have any mechanical resonance in the sensing bandwidth, and has very low sensitivity to the external acoustic or vibration induced noise sources.