Inter-pulse intensity correlation in gain-switched semiconductor laser for quantum key distribution
Yuanfei Gao, Tao Wang, Yixin Wang, Zhiliang L. Yuan · 2024
The transmitters in QKD usually employ a gain-switched semiconductor lasers (GSSL). Here, we investigated the intensity fluctuation and correlation between adjacent pulses. Strong intensity fluctuation and negative correlation were observed under low driving currents. Utilizing rate equations in our simulation, we confirmed the fluctuation resulted from an instability of GSSL at high repetition frequency. This work would be useful to test whether the transmitter is operating at optimal state.