Researchers from Stanford University have taken a big step forward in the development of light-based communications in computer chips. Laser optical interconnect systems already exist, but their new nanoscale LED setup improves the energy efficiency 2,000 times, sipping just 0.25 femto-joules per bit sent as compared to a laser's 500 femto-joules. In spite of this low power consumption, chips using the LEDs will reportedly be capable of transfer speeds of 10Gbps.
This data speed is achieved through using single-mode LEDs: normal LEDs give off light at a range of frequencies, whereas the Stanford team's new design creates a single frequency of light. Electricity is applied to dots of indium arsenide, which give off light as current passes through them. This is then focused by a photonic crystal, created by putting an array of holes into a semiconductor, which both forces the light to resonate at the desired frequency and acts as a focusing mirror, creating a beam of light.
The new technology is designed with the next generation of computer chips in mind, making optical computing viable at much lower power cost. Combined with other research into nanotechnology — including the reconfigurable circuits we saw last month — the drive towards faster, lower-powered computing shows no sign of slowing down.