Erbium-doped fiber laser tuning using two cascaded unbalanced Mach-Zehnderinterferometers as intracavity filter: Numerical analysis and experimentalconfirmation

We propose a new method for tuning an Er3+-doped continuous-wave fiber-ring laser. We present a novel numerical model and confirm the model with exper imental results. The numerical model relies on the implementation of the an alytical solution of signal propagation over small (elemental) segments of amplifier fiber rather than using the usual Runge-Kutta algorithm. The vali dity of the model is verified by the good agreement between computer result s and experimental data. Experiments demonstrating a 11.2-nm wavelength tun ing range have been conducted using an electrooptic intracavity filter comp osed of two cascaded unbalanced Mach-Zehnder interferometers (MZIs) integra ted in lithium niobate, The numerical analysis shows that the tuning range obtained is limited by the combination of gain shape and filter characteris tics. Increased tuning range can be obtained by decreasing losses or by usi ng a more selective filter.