We demonstrate an environmentally stable Kerr-type mode-locked erbium
fiber laser producing 360-fs near-bandwidth-limited pulses. Environmen
tally stable operation is possible in the presence of nonpolarization-
maintaining fiber components provided that their overall length is sho
rt compared with the length of the polarization-maintaining fiber comp
onents. The pulses are generated at a stable repetition rate of 27 MHz
and have an energy content of 60 pJ.