Nonlinear Dynamics in Semiconductor Lasers - Abstract

Verschaffelt, Guy

Dynamics of semiconductor ring lasers with filtered optical feedback for wavelength tuning

We discuss the performance and dynamics of semiconductor ring laser that are made wavelength tunable using on-chip filtered optical feedback. In this system, part of the light emitted by the laser is coupled back into the cavity after optical filtering. This tuning mechanism has the advantage that the laser and the feedback can be integrated on the same chip, yielding compact, robust and potentially low-cost devices. We show that, while the ring laser emits multiple longitudinal modes without feedback, the filtered optical feedback can be used to make the ring laser emit in a single longitudinal mode. The emission wavelength can be tuned between discrete values by changing the feedback strength in different wavelength channels. We measured the wavelength switching speed in this device to be as short as a few nanoseconds, and we discuss the role of the strength and the phase of the filtered feedback. We also show that the filtered feedback can be used to reduce the sensitivity of these semiconductor ring laser to conventional optical feedback and to optical injection.