Using an integrated colliding-pulse modelocked semiconductor-laser array, researchers at Technische Universiteit Eindhoven (The Netherlands) have demonstrated a period-doubling transition into chaos, indicating the existence of nonlinear dynamics in photonic integrated circuits (PICs). A lensed fiber was used to collect light from the laser-output waveguides; the signal was amplified using a semiconductor optical amplifier.
The researchers recorded the radio-frequency spectrum of the laser and performed a so-called Fokker-Planck analysis to reconstruct the deterministic content of the laser-output dynamics. They observed intrinsic nonlinear dynamics in the integrated active-photonic device under study. They also noted no less of a tendency toward nonlinear dynamics than in nonintegrated lasers consisting of individual optical components. Nonlinear dynamics actually play a major role in the function of photonic integrated laser circuits, according to the researchers. Consequently, analysis and visualization of nonlinear dynamics are expected to contribute to improved design of photonic integrated circuits. In comparison to stand-alone photonic devices, the dynamics of PICs appear to be more stable over the lifetime of the system, reproducible from batch to batch, and on faster time scales because of the small sizes of PICs, according to the researchers. Contact Mirvais Yousefi at [email protected].