Narrow-linewidth self-sweeping fiber laser with scanning range control by a tunable Lyot filter

To obtain broadly tunable narrow-linewidth generation in a self-sweeping fiber laser, we propose combining the broadband tunability of a Lyot filter and an adaptive filter based on dynamic grating. The grating is intrinsically formed in the laser active medium during the self-sweeping operation. Temperature control of the fiber Lyot filter and matching of the filter tuning and self-induced sweeping rates allows for an increase in the tuning range, from 20-42 nm in a Yb-doped fiber laser, keeping an instantaneous linewidth below the level of 20 MHz.