A Laser Modulation Driver in 130-nm CMOS Technology for Quantum Key Distribution System

Laser modulation is a process to modulate the photons to different states in quantum key distribution (QKD) system. A laser modulation driver, which is a pre-driver for the laser modulator, is presented in this paper. The laser modulation driver is implemented in a 130-nm complementary metal oxide semiconductor (CMOS) process. The laser modulation driver can provide a current pulse signal with an adjustable amplitude and an adjustable pulse-width to a distributed power amplifier. The pulse-width of the current signal can be adjusted from 300 ps to 3800 ps, the maximum adjustable amplitude is 14.4 mA, and the data rate can reach 625 Mb/s. According to the test results, the laser modulation driver can meet the requirements of the electro-optic modulator (EOM) in QKD system, and it can be used in the laser modulation circuit in QKD experiments.