Ultra-Low Optical Noise in Dual-State Quantum Dot Laser on Silicon Under Optical Injection Locking

This work theoretically reports on the low relative intensity noise (RIN) and narrow linewidth characteristics of dual-state quantum dot (QD) lasers epitaxially grown on silicon under optical injection locking. The results illustrate that optical injection locking effectively mitigates the influence of excited state (ES) emission on the ground state (GS) optical noise, resulting in a 22 dB reduction in GS RIN at the ES threshold. Within the optical-injection-locked area, both GS and ES RIN can be reduced by a minimum of 10 dB, enabling laser operation at high bias currents while maintaining lower RIN values in both states. Moreover, optical injection locking suppresses the spectral linewidth rebroadening observed at high bias currents, achieving ultra narrow spectral linewidth. This work provides an effective reference method for integrating ultra-low intensity noise and narrow spectral linewidth light sources into silicon-based photonic integrated circuits.