Optical frequency comb generation from a 1.65 μm single-section quantum well laser

Optical frequency combs (OFC5) in the 1.65 mu m wavelength band are promising for methane sensing and extended high-capacity optical communications. In this work, a frequency-modulated (FM) OFC is generated from a 1.65 mu m single-section quantum well laser. This is characterized by a 1 kHz-wide beatnote signal at similar to 19.4 GHz. Typical FM optical spectra are shown and optical linewidth of the OFC narrows through the mutual injection locking process in the comb formation. No distinct pulse train is observed on oscilloscope, which conforms with the FM operation. Furthermore, to add further evidence that tour-wave mixing (FWM) is the driving mechanism of the comb formation, FWM frequency conversion characterization is conducted on a semiconductor optical amplifier (SOA) fabricated together with the tested laser. An efficiency of similar to-30 dB confirms the capability of FM mode locking. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this study, a frequency-modulated optical frequency comb (OFC) is generated using a 1.65μm single-section quantum well laser. The comb formation process is characterized by narrowing of the optical linewidth through mutual injection locking. Furthermore, the driving mechanism of comb formation is confirmed to be four-wave mixing (FWM) through FWM frequency conversion characterization on a semiconductor optical amplifier.