A 59.1 GHz train of 2.2 ps solitons with low phase noise (<5×10−5) is generated by a novel, passive, all optical fibre source. The technique is based on transformation of a dual frequency beat signal generated by a 16 kHz line width erbium fibre DBR laser having a selectable and highly stable frequency separation, into a soliton train in a comblike dispersion profiled fibre, a novel fibre design which uses conventional optical fibres.