Unraveling the noise dynamics in photonic crystal Fano lasers: a comprehensive numerical study

We conduct a thorough analysis of the noise characteristics inherent to photonic crystal Fano lasers, specifically focusing on relative intensity noise (RIN) and frequency noise (FN). Utilizing both small signal and statistical methodologies, our findings reveal a significant discrepancy in noise levels between the cross-port and the through-port of the laser, with the former exhibiting markedly lower noise characteristics. Furthermore, our investigation demonstrates a notable trend: as the bias current increases, a corresponding decrease in the RIN level is observed across both ports. This intriguing relationship underscores the potential for optimizing performance through bias current modulation. Additionally, we examine the relationship between nanocavity quality factor (Q_NC) and output power, discovering that an increase in Q_NC leads to enhanced output power and a subsequent reduction in RIN levels. A critical component of our analysis focuses on the FN properties of the laser, where we emphasize the pivotal role of the nanocavity quality factor as a key design parameter. In this regard, we demonstrate that higher values of Q_NC correspond to a narrower laser linewidth, attributed to the longer photon dwelling time within the nanocavity compared to the propagation time in the laser cavity, quantified a 230 fs, which was also shown by others. Finally, we present a comparative analysis of the linewidth achieved from both ports of the Fano laser against that of the Fabry-Perot laser. These outcomes highlight the potential of the Fano laser in applications requiring low-noise and high-performance optical sources.