Low Noise Ultrashort Pulse Generation by Direct RF Modulation at 22 GHz From an AlGaInAs Multiple Quantum-Well Laser at 1.55

We report subpicosecond pulse generation at 22 GHz from a two-section passively mode-locked laser at 1.55 $mu{rm m}$, using a novel AlGaInAs quantum-well wafer. By carefully designing the metal pad and the isolation layer, we are able to hybridly mode-lock the laser by modulating the saturable absorber at the fundamental repetition rate and thus achieve a low timing jitter of ${sim}{rm 280}~{rm fs}$ (1 Hz–100 MHz).