Triple-wavelength switchable Erbium-doped fiber laser with cascaded asymmetric exposure long-period fiber gratings

The cascaded asymmetric exposure long-period fiber gratings are fabricated by CO2 laser, which provide multi-wavelength filters with anisotropic transmission spectrum under different states of polarization. Inserting this device in the ring cavity of an erbium-doped fiber laser, a triple-wavelength switchable lasing laser with equal spacing of 2.6nm has been obtained. Owing to the polarization dependent loss of the new cascaded long-period fiber grating, the wavelength switching of random combination of C-3(1), C-3(2) and C-3(3) is demonstrated through the polarization controlling. We derive the wavelength switch to the polarization characteristic of cascaded asymmetric exposure long-period fiber gratings. (c) 2007 Optical Society of America.