Ultrashort pulse generation from mode-locked erbium-doped fibre ring lasers

Abstract

A theoretical model of a passively mode-locked erbium-doped fibre ring laser using nonlinear polarization rotation is developed. Numerical simulations are used to study mode-locking and pulse dynamics in a typical ring configuration. The simulations show that stable operation can exist in both isotropic and birefringent fibres, and stable pulses with a FWHM as short as 45 fs can be generated. It is found that there is an optimal regime of ellipticity such that the stable mode-locking can be obtained. In addition, the condition for high birefringence approximation is also found.