Alternate multiwavelength modelocked fiber laser

We demonstrate alternate mode-locking of three 30-ps pulse trains at three different wavelengths, each at a repetition rate of 3.8 GHz. The successive multiwavelength pulsed operation is reached in an actively mode-locked erbium-doped fiber laser in which an unbalanced Mach-Zehnder interferometer has been introduced. This component plays both the role of intensity modulator and tunable filter.