Realization of coherent polarization locking of two orthogonal- polarization beams in a Mach-Zehnder compound cavity based on the polarization-dependence losses of a polarizer

摘要

We have proposed and successfully demonstrated coherent polarization locking of two orthogonal-polarization beams in a Mach-Zehnder Erbium-doped fiber laser (MZEDFL) cavity based on the polarization-dependence losses of a polarizer. The two orthogonal polarizations are locked coherently to produce a resultant polarization state that sees maximal loss to the polarizer and minimal loss to the output port. High efficiency of coherent polarization locking of two orthogonal-polarization beams is realized, even when the powers of the two branch arms are highly imbalanced (19.3/14.8). The coherent output power can range from 45mW to 0.6mW by adjusting the PC with 120 degrees. This outcome shows the range from polarization locking to polarization unlocking occurring in the 50:50 fused fiber coupler.