L-band tunable and switchable multi-wavelength erbium-doped fiber laser

Abstract

A simple and effective tunable and switchable L-band multi-wavelength polarization-maintaining erbium-doped fiber laser is proposed and demonstrated. A Mach-Zehnder interferometer with a fiber Bragg grating inside one arm used as the wavelength selective filter makes the output wavelength at the L band. The nonlinear polarization rotation effect induced by a 5-km long single mode fiber, a polarization controller (PC) and polarization-dependent isolator is used to effectively suppress the mode competition. Thus the stable all-fiber ring cavity structure with multi-function operation is realized. The laser outputs of the single-wavelength can be tuned about 12 nm with an interval of 1 nm in L band. The side-mode suppression ratios (SMSRs) of these lasing lines are all over 60 dB. And single-wavelength, dual-wavelength, triple-wavelength and quadruple-wavelength can be switched by appropriately adjusting the PC. The SMSRs of multiwavelength lasing lines are all over 50 dB. The laser has the advantages of simple all-fiber configuration, low cost, high stability and operating at room temperature.