Abstract
A scheme to produce wavelength-tunable pulses with gigahertz bit rate is demonstrated by active mode locking of a fiber laser. Fiber gratings are used in the setup to play the simultaneous roles of wavelength selective mirrors, tunable optical filters, and output fiber couplers. Single- and dual-wavelength picosecond pulses are generated with a flexibility of switching between the outputs by polarization adjustment. A strain tuning process is successfully developed and a total operating range of 13.62 nm towards both shorter and longer wavelengths is demonstrated. Our experimental observations are in good agreement with the calculated results.