10 GHz AlGaInAs/InP 1.55 μm passively mode-locked laser with low divergence angle and timing jitter.

We present a 10 GHz 1.55 μm all-active passively mode-locked laser based on a novel AlGaInAs/InP epitaxial structure with a three-quantum-well active layer and a passive far-field reduction layer. The device generated 1.06 ps pulses with a state-of-the-art timing jitter value of 194 fs (4-80 MHz), and a radio-frequency linewidth of 2 kHz, while demonstrating a low divergence angle (14.7° × 27.3°) with a twofold butt coupling efficiency to a flat cleaved single mode fiber, compared to the conventional five-quantum-well MLLs.