Ultrafast, nanoscale, energy-efficient data transmission
November 29, 2011
A new ultrafast, nanoscale light-emitting diode (LED) device developed at Stanford’s School of Engineering transmits data at ultrafast rates while using 2,000 times less energy than laser-based systems in use today,” The nanophotonic device is a major step forward for on-chip data transmission, the researchers say.
The device can transmit data at 10 gigabits per second. The researchers say it is a major step forward in providing a practical ultrafast, low-power, room-temperature light source for on-chip data transmission.
The LED is a “single-mode LED,” a special type of diode that emits light more or less at a single wavelength, similar to a laser. Traditionally, engineers have thought only lasers can communicate at high data rates and ultralow power.
Nanophotonics is key to the technology. In the heart of their device, the engineers have inserted quantum dots using the light-emitting material indium arsenide, which, when pulsed with electricity, produce light. These quantum dots are surrounded by a photonic crystal — an array of tiny holes etched in a semiconductor. The photonic crystal serves as a mirror that bounces the light toward the center of the device, confining it inside the LED and forcing it to resonate at a single frequency.
Existing devices are actually two devices: a laser coupled with an external modulator. Both devices require electricity. The diode combines light transmission and modulation functions into one device, drastically reducing energy consumption.
Ref.: Gary Shambat et al., Ultrafast direct modulation of a single-mode photonic crystal nanocavity light-emitting diode, Nature Communications, 2011 [doi:10.1038/ncomms1543]