Generation of sequences of ultrashort pulses in erbium doped fibre single ring lasers

Active and passive mode locking has been observed in an erbium doped fibre single ring laser. Pulse durations as short as 100 fs at a repetition rate of 300 GHz have been measured from an erbium doped fibre amplification stage placed at the output of the fibre ring. The ultrafast regime depends critically on the dynamical evolution of the light polarisation along the cavity.