Tailoring The Output Laser Wavelength Of Fiber Lasers By The Intra-Cavity Inscription Of Lpfgs

Tailoring of the output laser spectral characteristics of an Erbium-doped fiber laser (EDFL) by the intra-cavity inscription of long-period fiber gratings (LPFGs) is experimentally demonstrated. The intra-cavity fabrication allows the accurate positioning of the LPFG notch bands in order to tailor the laser wavelength and at the same time suppress the side modes on the output laser spectrum. The red tail of the LPFG notch band is used as an edge filter to modify the gain spectrum, since its shape or slope is modified as the LPFG strength grows. As few as three periods are enough to tailor the laser wavelengths to a single laser line operation, with a side mode suppression ratio (SMSR) of 34.2 dB; while at six periods 37.79 dB of SMSR in a dual wavelength operation is demonstrated. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1430-1433, 2016