Self-oscillating optical frequency comb generation based on the gain-switching dual-tone semiconductor laser

Abstract

A novel method to generate the optical frequency comb (OFC) based on the gain-switching integrated semiconductor laser is proposed in this paper. In the system, by modulating the core device, i.e., dual-tone monolithic integrated semiconductor laser (DT-MISL), which is biased appropriately, with an enough large amplitude RF signal, it would be pushed into the gain-switching state and thus various OFCs with distinct comb lines can be generated. The superior advantage here is that the RF modulation signal is offered by the local oscillator, which can be originally generated after the photodetector based on the DT-MISL itself. In this case, no additional external microwave driver is required and thus the OFC generator is fully self-oscillating. To my best of knowledge, it is the first try based on the integrated laser source under the gain-switching state. Compared to other discrete systems, this compact structure is potential to develop for photonic integration. In the experiment, one discernible OFC with 114.448-GHz bandwidth and 17 comb lines within 10-dB amplitude variation is obtained, indicating the feasibility of this scheme. In addition, the tunability and the application of the OFCs in the generation of the multi-carrier signals are discussed at last.© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement