A Switchable and Tunable Dual-Wavelength Actively Mode-Locked Fiber Laser Based on Dispersion Tuning

A switchable and tunable dual-wavelength actively mode-locked fiber laser based on a dispersion tuning technique is proposed and demonstrated. Synchronous wavelength tuning of dual-wavelength operation with wavelength spacing of 22.9 nm can be achieved up to 23.2 nm by changing the modulation frequency. The proposed laser can operate in dual-wavelength or single-wavelength by simple adjustment of the polarization controller. Moreover, wavelength spacing can also be varied from 22 to 45 nm at the cost of a reduced tuning range by changing the harmonic order, which is determined by the modulation frequency. These experimental observations agree well with the theoretical analysis.