Generation of 1.2 ps, 10 GHz pulse train from all-opticallymodelocked,erbium fibre ring laser with active nonlinear polarisation rotation

1.2 ps transform-limited pulses at 10 GHz have been successfully generated from an all-optical, actively modelocked ring laser. The laser is actively modelocked with a stream of optical pulses that produce a periodic phase modulation and polarisation rotation in the fibre modulator. A polariser installed in the cavity plays an important role in converting the polarisation rotation into amplitude modulation.