Analyzing Frequency Combs in Multi-section Hybrid Silicon Quantum Dot Laser Using Hanbury Brown-Twiss Measurements

We propose a novel method to characterize mode-locking regimes using a hybrid InAs/GaAs quantum dot frequency comb laser developed on silicon. By implementing Hanbury Brown-Twiss setup, measurements of zero-delay second-order correlation function g⁽²⁾(0) indicates that, in contrast to the frequency-modulated comb regime, the laser operating in amplitude-modulated comb regime exhibits higher g⁽²⁾(0) value, implying that photon bunching is enhanced when optical pulse starts to form. This work not only suggests a hardware-wise simple method to monitor frequency comb behaviors, but also unveil that there are more to understand for the comb generation from the perception of quantum physics.