Mode-locked fiber laser based on an attenuation-imbalanced nonlinear optical loop mirror

We propose a mode-locked figure-eight fiber laser by utilizing an attenuation-imbalanced nonlinear optical loop mirror (AI-NOLM) for the first time. Stable self-starting passively mode-locked pulses as short as 296 fs are obtained. We have also confirmed that the pulse width of the laser can be varied by changing the amount of attenuation in the AI-NOLM.