Influence of Optical Feedback Strength on Intensity Noise and Photon Number Probability Distribution of InGaAsP/InP Laser

We have systematically investigated how the strength of optical feedback (OFB) affects the dynamics, noise levels, and photon number probability density distribution (PNPDD) in time-delayed semiconductor lasers (SLs). We find that intensity noise decreases in both weak and strong OFB regimes. The shape of the PNPDDs changes based on OFB strength: it shifts from symmetric to asymmetric based on the OFB strength. In the chaotic region, the PNPDDs display a peak at low intensity and taper off at multiples of the average photon number. The results of this work suggest that operating SLs under weak or strong OFB conditions may help to minimize instability.