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.

Sjeev John, a professor of U of T's Department of Physics 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.