3d waveguide is promising for optical computers

Researchers have created a new process for making complex miniature waveguides that can steer optical signals in three dimensions through solid materials. All optical computers could approach the theoretical speed of a photonic switch which is estimated to be on the order of petahertz (10**15). They should definitely achieve multi-terahertz speeds. So 1000 to 1 million times faster than current computers at 4 Gigahertz (4 * 10**9).

MIT has another approach which they hope will yield all optical computers by 2012

A 3-D waveguide carved into photonic crystals, he says, “can be used to trap and control light, and has potential applications in everything from more-efficient lasers to optical signal processing for telecommunications or other applications,” he says.

Photonic crystals can be made by packing together beads of silica. When they’re packed together in a precise three-dimensional arrangement, it is possible to create what is known as a complete photonic bandgap material. This material, says Braun, will act as a perfect reflector for a particular narrow band of light–dictated by the size of the beads. “It’s a perfect reflector for all angles of incidence.”

If channels can be created within the material, any light entering the material via these channels will not be able to escape, except through the channels. So once in the material, it becomes possible to manipulate the light in unusual ways, such as by trapping it or bending it around very sharp corners without fear of it escaping.

Braun’s group has gotten low refraction problems by using the polymer as a template for creating a complete photonic bandgap material out of silicon, which has a higher refractive index.

While Braun’s structures are not yet useful for making working devices, they are an important first step toward creating more complex and functional optical devices.

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