Effect of External Optical Feedback on Tunable Micro-Ring Lasers Using On-Chip Filtered Feedback

We experimentally and numerically study the influence of external optical feedback on semiconductor ring lasers, which are wavelength tunable using on-chip filtered optical feedback. We investigate the dynamics in the laser's intensity due to the conventional optical feedback and how this dynamics is changed by adding filtered optical feedback. Experimental observations show that the filtered optical feedback shifts the onset of the feedback-induced dynamics to larger values of the feedback rate. We are able to numerically reproduce the experimental observations using a rate equations model.