Mode-locked erbium-doped fibre ring laser using nonlinear polarization rotation

Abstract

We present a theoretical study of a fibre ring laser in which mode locking is achieved by the combined action of weak intrinsic birefringence and self-induced birefringence. Numerical simulations show that stable operation can exist in wide ranges of parameters, and stable pulses with a full width at half-maximum as short as 55 fs can be generated. It is also shown that coherent coupling may greatly enhance mode locking in a weakly linearly birefringent fibre under optimum operation conditions.