A frequency-shifted feedback fiber laser and its application to optical measurements

摘要

In frequency-shifted feedback lasers (FSF lasers), a frequency shift is imposed on an intracavity light field by feedback of the first-order diffracted light of an acousto-optic modulator. In this report, we describe the performance of the FSF laser with an erbium-doped fiber as a gain medium and its application to measurements for group velocity dispersion and polarization mode dispersion of optical fibers. We also describe a new FSF laser which incorporates an active mode-locking technique. Because of the mode-locking mechanism, the phase between the modes are completely locked, and this indicates that one can greatly improve the signal to noise ratio of the beat signal (> 20 dB) in optical homodyne measurements.