Active mode-locking of conventional diode laser by using external cavity

We have actively mode-locked a commercially available conventional diode laser by using an external cavity. A single layer anti-reflection coating was applied to the output end surface of the laser diode. The laser was driven by ultrashort current pulses from a comb generator, and the pulse separation and the round trip time of the cavity were made equal to 10.56 ns. The output was a clean single-peak pulse train without any side peaks. The pulse width measured by a synchroscan streak camera was 20 ps.