Tunable multi-wavelength Er-doped fiber laser based on a fiber taper

We demonstrate a multi-wavelength Er-doped fiber laser at room temperature by using a fiber taper as an optical comb filter. A taper filter fabricated with a flame brushing technique has a filter period of 1.9 nm and modulation depth of 9.7 dB. Four-wave-mixing induced by a 400 m SMF-28e fiber was employed to suppress the mode-competition. Stable cw laser with 11 lasing lines was obtained with a wavelength spacing of 1.9 nm by appropriately setting the pump strength and laser polarization state. The multi-wavelength fiber laser could be precisely tuned through carefully stretching the fiber taper. (paper)