Faint-Pulse Single-Photon Source Triggered by FPGA

Among various implementations of single-photon sources, faint-pulse single-photon sources provide a simple and practical approach based on attenuated coherent laser pulses. This work presents an experimental realization of a faint-pulse single-photon source using a 785-nm Grating Stabilized Laser Diode system, driven by a laser diode controller and modulated by a Field Programmable Gate Array (FPGA). The system's performance was evaluated by analyzing the photon detection rate as a function of pulse width and driving current. Results indicated a linear relationship between the single-photon detection rate and pulse width and an exponential dependence on driving current. The system achieved a photon emission probability of 10% per pulse, aligning with the requirements of practical quantum key distribution systems. This implementation demonstrates a cost-effective, scalable, and accessible platform for single-photon experiments, providing a foundation for future implementations of quantum communication protocols.