Comparison of linewidth narrowing in quantum-dot and quantum-well integrated III-V/SiN lasers

Abstract This paper describes an analysis of integrated III-V/SiN lasers operating with quantum-dot and quantum-well active regions. We focus on the effects of 0- and 2-dimensional carrier densities of states on linewidth narrowing. The theoretical approach includes a) multimode laser interaction to treat mode competition and wave mixing, b) quantum-optical contributions from spontaneous emission and c) composite laser/free-space eigenmodes to describe outcoupling and coupling among components within an extended cavity. The approach is able to describe the progression to Hz-level lasing linewidth observed in III-V/SiN lasers with quantum-dot active regions. In addition, it predicts that the integration of III-V/SiN mitigates the high quantum-well linewidth enhancement factor, resulting in similar Hz-level linewidth performance. Tradeoffs are explored among linewidth, output power and injection current.