Abstract
In a linear Nd3+ fiber laser, spatial hole burning is eliminated by frequency shifters at the ends of the cavity. They introduce a frequency difference of 160 MHz between the two counterpropagating waves. The laser operates spontaneously and stable on a single longitudinal mode with ≊12 kHz bandwidth near 1088 nm. Tuning over 16.5 nm is achieved by two piezoelectrically driven etalons.