Fiber lasers with hybrid birefringence resonators

We propose the combination of low- and high-birefringence fibers (Low-Bi and Hi-Bi, respectively) to form a hybrid birefringence resonator. The transmission characteristics as a function of different parameters for the fibers used within these hybrid resonators are obtained by means of Jones matrix analysis. This yields information on fiber laser features such as polarization mode-beating frequencies (PMB), which are used as readout for polarimetric sensors. We compare theoretical predictions with experimental results on the dependence of PMB frequencies as a function of wavelength and effective birefringence of the laser cavity. Applications of this hybrid fiber laser arrangement for polarimetric sensors and wavelength monitoring through PMB frequencies are also discussed. The results provide a simple way for optimizing fiber laser parameters and increase the sensitivity of PMB signals to wavelength variations.