Using nanotechnology, researchers at Stanford University claim to have created a smaller, more efficient and faster laser than those commonly used in optical communications today. But commercial use of the innovation is likely years away.

In a paper recently published in the journal Optics Express, Stanford scientists Hatice Altug and Jelena Vuckovic demonstrated a new type of single-mode laser made from a photonic crystal riddled with tiny empty holes, or nanocavities.

Altug and Vuckovic’s laser was built using a square of sandwiched indium phosphide material less than 300 nanometers thick (300 millionths of a millimeter). On it, an array of 81 cavities (9 by 9) were evenly spaced. Light was contained in the indium phosphide sandwich, resonating by bouncing off the walls of the tiny holes (since the air inside the holes has a different refractive index than the indium phosphide).

The scientists claim this method is more efficient than the common method used in today’s lasers: vertical cavity surface-emitting lasers (VCSELs). VCSELs use vertical stacks of Gallium Arsenide material to contain and resonate light, a similar method of “distributed refraction” used by Altug and Vuckovic. But the new laser’s 9-by-9 grid of holes does in two dimensions what VCSELs do in one, using a much smaller space to yield a similar output. Whereas a typical VCSEL might be several micrometers wide in diameter, Altug and Vuckovic’s laser is a few hundred nanometers--10 to 50 times smaller.

“This is the key to achieving lasing at much lower thresholds and, theoretically, much higher modulation speeds,” Vuckovic said.

The new laser wouldn’t require the addition of a separate modulator to turn it on and off rapidly, creating a signal, as continuous-wave lasers do. Instead it could be modulated directly at speeds over 100 Gb/s, Vuckovic said, while VCSELs can’t be directly modulated faster than about 10 Gb/s to 20 Gb/s.

In addition, the new laser should consume less power than today’s commercial lasers, she said. In the demonstration described in the paper, the laser consumed about 2.5 milliwatts--not much less than typical VCSELs. But Vuckovic said that level could be lowered an order of magnitude or more--to a few hundred microwatts.

However, Vuckovic can’t predict when the technology might show up in commercial communication products. For one thing, the scientists used another laser as the initial light source for the demonstration. To make it independent, they will have to pump it electrically instead, which could take one or two years.