Single ultrashort optical pulses (2ps with 17.6 GHz repetition rate) have been generated with hybrid mode-locked monolithic GaAs/AIGaAs lasers at λ = 856nm. Instead of an external cavity, long active waveguides were used as resonators with a roundtrip frequency of 5.9 GHz. Increasing the pump current in the waveguide far above transparency led to 10 ps pulses with a high peak power of 110 mW. © 1991, The Institution of Electrical Engineers. All rights reserved.