Controlled multi wavelength emission using semiconductor ring laser with on-chip filtered optical feedback

We report on an integrated approach to obtain multi-wavelength emission from semiconductor ring laser with filtered optical feedback. The filtered feedback is realized on-chip employing two arrayed-waveguide gratings to split/recombine light into different wavelength channels. Through experimental observations and numerical simulations, we find the effective gains of the different modes is the key parameter which has to be balanced in order to achieve multi-wavelength emission. This can be achieved by tuning the injection current in each amplifier.