20 channels simultaneous oscillation from a semiconductor fibre laser

We report the demonstration of a stable laser source capable of generating up to 20 wavelengths, with a 100 GHz line spacing and linewidth less than 1.25 GHz. In addition the power variation across the most intense oscillating lines was less than 3 dB. The source operates at room temperature and uses an SOA as gain medium, a polarization maintaining fiber based Lyot filter and two nonlinear optical loop mirrors, which form a linear cavity. By using NOLMs as reflectors to form a linear cavity and by using only low loss, fibre components, the end-to-end loss in the cavity is minimised and thus, more channels may oscillate.