Experiments Take Step Toward Micro Photonic Chips

The creation of photonic chips at the micron scale may not be too far off, as seen in an experiment involving silicon photonic crystal.

Work by an international group of researchers — led by the University of Sydney’s CUDOS (Australian Research Council Centre of Excellence for Ultrahigh bandwidth Devices for Optical Systems) — has demonstrated the soliton-effect pulse compression of picosecond pulses in silicon photonic crystal.

Compression of 3.7-ps pulses to 1.6 ps with <10 pJ energy was demonstrated, as was a ~1-ps free-carrier-induced pulse acceleration, despite the typical difficulty presented by two-photon absorption and accompanying free carriers.

Researchers injected 3.7-ps pulses into a 396-m dispersion-engineered silicon PhC-wg to demonstrate soliton compression in silicon. Courtesy of Nature Communications.

This proves that picosecond input pulses are critical, the researchers said. The measurements have been backed by a nonlinear Schrödinger model.

The experiments used dispersion-engineered slow-light photonic crystal waveguides, along with an ultrasensitive frequency-resolved electrical gating technique, which allowed them to detect the ultralow energies in the nanostructured device; these results should increase our understanding of nonlinear waves in silicon.

The experiment also paves the way for soliton-based functionalities in complementary metal oxide semiconductor (CMOS) compatible platforms, and for solid integration of microelectronics and photonics at the micron scale.

Traditionally, similar experiments have used optical fibers or silica glass-based photonic crystal fibers. These are not suitable for photonic integration, however, prompting the search for alternative platforms, such as plasmonics and high-index glasses and silicon semiconductor materials.

Results of the experiments are a significant step toward developing miniaturized optical components featuring soliton-based functionality for photonic chips.

The research is published in Nature Communications.

For more information, visit: www.sydney.edu.au/science/physics/cudos.