  For the first time, we present the pump power-controlled wavelength-tunable
mode-locked fiber laser in the L-band (1565 nm to 1625 nm), achieved by
all-polarization maintaining (all-PM) nonlinear polarization rotation (NPR).
The wavelength of the laser can be tuned over 20 nm, from 1568.2 nm to 1588.9
nm simply by controlling the pump power from 45 mW to 115 mW. In contrast to
conventional wavelength tuning mechanisms such as optical bandpass filters, our
tuning method is non-mechanical and electrically controllable, featuring
simplicity and cost-effectiveness in a superior all-fiber design.
