Crystal structures light the way to optical microchip

A new class of microscopic crystal structures developed at the University of Toronto is bringing high bandwidth optical microchips one step closer to efficient, large-scale fabrication. The structures, known as photonic band gap (PBG) materials, could usher in an era of speedy computer and telecommunications networks that use light instead of electrons.

“This will be a tremendous breakthrough,” says Sajeev John, a professor in U of T’s Department of Physics and co-investigator of the study published in the June 7-13 issue of Physical Review Letters. “It’s basically a whole new set of architectures for manufacturing nearly perfect photonic band gap materials and will provide an enormous increase in the available bandwidth for the optical microchip.”

John and his team devised a photonic band gap blueprint that can be made with nanometre-scale precision by bombarding it with x-rays. The x-rays pass through a gold “mask” with an array of holes, removing portions of a polymer template below. Glass is deposited to fill in the holes and the remaining polymer burned away with heat. Silicon is then deposited throughout the void regions of the glass template and the glass finally removed with chemicals, leaving behind a pure silicon photonic band gap material.

The study was co-written with physics graduate student Ovidiu Toader and Mona Berciu, a physics professor at the University of British Columbia, and funded by the Natural Sciences and Engineering Research Council of Canada. CONTACT: Professor Sajeev John, Department of Physics, 416-978-3459, john@physics.utoronto.ca or Nicolle Wahl, U of T public affairs, 416-978-6974, nicolle.wahl@utoronto.ca