Numerical analysis of multifrequency erbium-doped fibre ring laser employing periodic filter and frequency shifter

Numerical analysis of a recently proposed multifrequency erbium-doped ring laser employing a frequency periodic filter and frequency shifter is presen ted. The model is based on a homogeneously broadened three-level approximat ion of an erbium ion. The multifrequency operation is achieved by shifting the frequency of the amplified spontaneous emission (ASE) power circulating in the ring cavity by one wavelength slot each circulation period to preve nt steady-state single-frequency laser operation. The effect of cavity loss , erbium-doped fibre (EDF) gain, direction of ASE circulation on lasing spe ctrum uniformity and output power is investigated.