Graphene Could Usher in New Silicon-based Photonic Circuitry

While IBM researchers were reporting one breakthrough after another in applying graphene to electronics this year (see here and here) researchers at the University of Cambridge in the UK and CNRS in Grenoble, France were busy applying the new wonder material to optoelectronic applications.

The Europe-based researchers fabricated a device that demonstrated “the most wideband saturable light absorber ever”. But not to be outdone in applying graphene to the field of optoelectronics, IBM has quickly reported on their own research of using graphene as a photodetector in an optical link fabricated on a silicon-on-insulator (SOI) substrate.

The graphene photodetector has proven itself to be effective over a wide bandwidth between 300 nanometers to 6 microns, which could make the optical link useful for applications beyond just communications “but for remote sensing, environmental monitoring and surveillance.”

Photodectors that are effective within these wavelengths have typically been made from III-V semiconductor materials, such as gallium nitride. But in this new research by being able to fabricate the optical link on a conventional SOI substrate the possibility of fabricating photonic circuits with CMOS processes seems as though it may be within reach.

As the author of the EE Times article speculates on his own blog:

“Silicon photonics is the holy grail of optical communications, enabling cheap integrated optics that handle all high-speed communications among chips and even among on-chip cores. Now IBM has demonstrated the last piece of the photonics toolkit--an optical receiver on a silicon-on-insulator substrate (SoI). Look for optical chips that integrate graphene with CMOS in five years.”