2.07- $\mu$ m, 10-GHz Repetition Rate, Multi-Wavelength Actively Mode-Locked Fiber Laser

We propose and demonstrate a multi-wavelength actively mode-locked fiber laser around $2.07~\mu \text{m}$ . A holmium-doped fiber is used as the gain medium which is pumped by a 1.93- $\mu \text{m}$ fiber laser. The multi-wavelength laser is achieved by employing a fiber Lyot filter in cavity, and actively mode-locking is achieved by driving a sinusoidal radio frequency signal on the electro-optic modulator. Stable actively mode-locked pulses can be obtained with up to 10.078-GHz repetition rate. The shortest measured pulse width is 16 ps. The wavelength channels can be accurately tuned under a fixed pump power by adjusting the polarization controllers and the BIAS voltage. Up to 27 channels can be obtained under a stable mode-locked operation. However, the increase of output channels leads to a significant increase in the threshold, and the maximum output channels have a strong dependence on the repetition rate.