Spectral Broadening in a Polarization-Maintaining Photonic Crystal Fibre by Femtosecond Pulses from an Optical Parametric Amplifier

The spectral broadening with the bandwidth of 83 nm (1.2486–1.3318 μm) in the 1.3 μm region is achieved in a 0.2-m-long, polarization-maintaining photonic crystal fibre (PCF) with an average core radius of 1.8 μm, pumped by optical pulses at the wavelength 1.269 μm, with the duration 250 fs and the repetition rate 250 kHz from an optical parametric amplifier. The polarization characteristics of the output spectra are also investigated.