Fibre laser system with wavelength tuning in extended telecom range

We report on a laser system on the base of a fibre telecom source, a chirped pulse amplification system, and low-birefringence large mode area photonic crystal fibre (LMA PCF) generating similar to 100 fs pulses with the energy similar to 10 nJ in the 1600-1700 nm wavelength range. The characteristics of the output spectrum corresponding to Raman solitons are studied for different polarisations of the pump pulse at the input of the PCF. We have shown that the wavelength of the output spectrum maximum can be tuned in the whole long (L) and ultra-long (U) telecom bands by adjusting the polarisation state of the pump pulse while the output power is constant.