Modeling of polarization-mode competition in fiber DFB lasers

A comprehensive model for steady-state analysis of polarization-mode competition in fiber distributed feedback (DFB) lasers is presented. Effects of polarization-dependent grating nonuniformities, polarization-dependent grating strength, coupling between the linear polarization states due to twist or Faraday rotation, back reflections, cross saturation from serially multiplexed lasers, as well as spatially and polarization-dependent gain hole burning are covered by the model. Regimes of single and dual polarization operation are identified for different types of polarization imperfections in the cavity, The output powers of the individual modes and the magnitudes of the hole-burning mechanisms are also calculated and discussed.