4 October 2010


Leti integrates CMOS-compatible plasmonic optical waveguides with silicon photonic devices

Leti of Grenoble, France, the Laboratory for Electronics & Information Technology of the French government's research and technology organization CEA, has demonstrated the integration of silicon photonic devices with fully complementary metal-oxide semiconductor (CMOS)-compatible plasmonic optical waveguides.

The R&D institute reckons that the new capability sets the stage for the fabrication of smaller, faster and more efficient optoelectronic interfaces, which could ultimately allow the development of much higher-performance sensors, computer chips and other electronic components.

Leti’s new devices channel light through a narrow silicon waveguide placed in close proximity to a metal waveguide, causing the light to excite small, high-frequency electromagnetic waves (surface plasmons) in the metallic structures. The resulting devices can convert optical signals in the 1.5µm communications band into plasmonic electron waves, and convert the plasmonic waves back into optical signals.

Leti’s combination of extremely small plasmonic-optical interfaces that connect to standard optical fibers provides high coupling efficiencies (up to 70%) over a wide spectral range. Also, unlike previous devices that have relied on metal waveguides made from gold, Leti’s metal waveguides are fabricated from copper, allowing easy integration into standard CMOS chip manufacturing processes.

“This demonstration of CMOS-compatible plasmonic-optical technology is a major milestone in the emerging field of metal-oxide-semiconductor photonics,” claims Laurent Fulbert, photonics program manager at Leti. “By concentrating light into very small modes, we can provide an efficient optical interface between the macroscopic world of optical fibers and the nano-scale world of transistors and molecular electronic devices.”

The plasmonic-optical devices were designed and fabricated by Leti, which collaborated with France's Université de Technologie de Troyes (UTT) for additional near-field scanning optical microscope (NSOM) testing and characterization. The project results were presented at the 7th IEEE International Conference on Group Four Photonics (GFP 2010) in Beijing, China in early September, and published in Nano Letters (2010) vol.10 (issue 8) p2922.

See related items:

Leti demos fully CMOS-compatible laser source coupled to silicon waveguide

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