Abstract: In the high-speed machine device independent quantum key distribution (MDI-QKD) system, the high code rate is crucial to realize long-distance quantum communication. To achieve a higher code rate, each link of the system has more requirements on the light source. To achieve the requirements, we design the pulse laser circuit for the high-speed MDI-QKD system. By analog processing and driving the external or internal trigger signal, the circuit can generate the pulse laser. By analog PID control bidirectional TEC current control, the circuit can stabilize the temperature. The outgoing pulse laser achieves a repetition of up to 1.25 GHz, a full width at half maximum of 24.2 ps, an extinction ratio of 30 dB, a wavelength jitter of 0.95 pm and a wavelength tuning range of 2.014 nm, which is beneficial to the improvement of the code rate. The pulse laser circuit meets the requirements of the high-speed MDI-QKD system.

Key words: laser techniques, quantum key distribution, pulse laser, high repetition rate, narrow pulse width