Single/dual-wavelength switchable and tunable passively Q-switched erbium-doped fiber laser

We demonstrate a passively Q-switched erbium-doped fiber laser (EDFL) with a birefringent Sagnac loop mirror (SLM) that combines the gain spectrum enables the laser to operate in tunable and switchable single/dual-wavelength states. When the pump power is up to 300 mW, the stable Q-switched pulse with the repetition rate and pulse duration of 58.57 kHz and 17.07 mu s is achieved by properly adjusting the polarization controller-1 (PC1) in the cavity. Meanwhile, the tunable and switchable single wavelength and dual wavelength regime is achieved by modulating the PC-2 in SLM, whose tunable ranges of single and dual wavelength are 3.27 nm and 1.69 nm, respectively. The proposed laser may meet the great application demands in nonlinear optics at 1.5 mu m band.