Flexibly tunable multiwavelength erbium-doped fiber laser based on four-wave mixing effect in dispersion-shifted fibers.

We experimentally demonstrate a flexibly tunable multiwavelength erbium-doped fiber laser based on degenerate four-wave mixing in a dispersion-shifted fiber. We successfully achieve the stable operation of the multiwavelength erbium-doped fiber laser at room temperature. The number of channels and wavelength spacing of the proposed multiwavelength laser can be controlled by the combination of two polarization maintaining fiber segments in the intracavity Lyot-Sagnac filter. We achieve 1.0 nm-spacing eleven channel and 0.8 nm-spacing seventeen channel lasing wavelengths at room temperature. The lasing wavelength of multiwavelength fiber laser can be also controlled by the polarization controller.