Generation of extremely short pulses from self-hybrid mode-locking of semiconductor lasers

Hybrid mode-locking, combining active mode-locking and passive mode-locking, has both advantages of generating very short pulses and low timing jitter. However, it usually requires an additional section of saturable absorber. Therefore, hybrid mode-locking is relatively difficult and complex compared to other methods. In this work, we report that pulses as short as 1-2 ps can be generated with novel self-hybrid mode-locking technique. With suitable bias and RF modulation depth, this scheme has the action of saturable absorption self-provided by the gain region of a conventional semiconductor laser amplifier. Therefore, multiple sections are no longer needed and the hybrid mode-locking can be achieved