Compensated dispersion tuning in harmonically mode-locked fiber laser

Electrical tuning of wavelength has been demonstrated in a harmonically mode-locked fiber laser using a compensated dispersion-tuning approach. The cavity consists of a standard single-mode fiber (SMF) and a dispersion-compensated fiber (DCF), providing equal and opposite group velocity dispersion to wavelength components around 1.55 mu m. Tuning is achieved by controlling the delay time between electrical pulse signals applied to two modulators connecting the SMF and the DCF. The tuning relation exhibits a linear characteristic and matches with the calculated result. A 21.5 nm tuning range is obtained with an extinction ratio as high as 47 dB at a constant operating frequency of 1 GHz. (C) 1999 American Institute of Physics. [S0003-6951(99)02733-3].