Date: 23/12/2011
Micron size diode for light can leapfrog data processing speed
Researchers at Purdue University have developed passive optical diode measuring a diameter of 10 microns (not visible to naked eye) using the popular semiconductor material silicon. This device is capable of getting integrated into semiconductor chips without interface hurdles. Well, anything which process light instead of electrical current is much faster and can lead to supercomputer on a chip. The release states this device does not require external assistance to transmit signals and can be readily integrated into computer chips.
Just like the semiconductor diode behaves to an electrical signal, this diode transmits signals (light) in only one direction, making it capable of information processing.
Minghao Qi, Associate Professor of electrical and computer engineering at Purdue University says, this one-way transmission is the most fundamental part of a logic circuit, so our diodes open the door to optical information processing.
More details of this innovation is published in the journal Science authored by students Li Fan, Jian Wang, Leo Varghese, Hao Shen and Ben Niu, research associate Yi Xuan, and Weiner and Qi.
The device is expected to solve the information speed bottleneck when the electrical signal is converted to optical signal and vice versa; both inside the device and the in the transmission cables.
These simple optical diodes are expected to remove changeover bottleneck by allowing the light signal to land directly inside the computer. The new optical diodes are said to be compatible with industry manufacturing processes for complementary metal-oxide-semiconductors, or CMOS, used to produce computer chips, Li Fan said. She adds, these diodes are very compact, and they have other attributes that make them attractive as a potential component for future photonic information processing chips.
These devices can also offer increased level of security to the supercomputers systems preventing them form cyber-attack.
Along with increasing the bandwidth and data transmission of whole communication system, these light diode can interconnect chips with optical links rather than copper wires.
Infrared light from a laser after passing through optical fiber and waveguide, it passes sequentially through two silicon rings and undergoes "nonlinear interaction" while inside the tiny rings. Depending on which ring the light enters first, it will either pass in the forward direction or be dissipated in the backward direction, making for one-way transmission, explained in the release. The rings can be tuned by heating them using a "microheater," which changes the wavelengths at which they transmit, making it possible to handle a broad frequency range, stated in the release.
The above picture simplifies the understanding of this diode