Multiwavelength semiconductor fibre ring laser utilising a Lyot filter

A multiwavelength semiconductor ring laser is presented with more than 30 wavelength channels at uniform powers. A polarisation maintaining fibre Lyot filter forms part of the ring and forces multiwavelength operation. The cw characteristics of the system are presented with reference to the number of channels and the channel uniformity, various wavelength spacings are demonstrated. The system is harmonically mode-locked at 1 GHz producing pulsewidths of 100 ps and the pulse train synchronisation between oscillating wavelengths is shown.