No. 312: An all-optic switching memory element with less than one milliampere operating current (September 19, 2011)

Two professors of Nara Institute of ScienceTechnology successfully reduced the operating current of an all-optic switching memory element to less than one milliampere. This technology is expected to open up the road to high-speed optical routers. The semiconductor laser directly receives optical signals transmitted through the communication circuit, and inputs and outputs information as a form of polarized light that oscillates in a certain direction. They successfully reduced the current with the help of the oxide-confined structure that narrows down the passage of current inside a semiconductor laser.

If easily oxidizable layers, oxide-confined layers, are arranged near an active layer, the oxidation of the active layer starts with the surrounding area should vapor be applied to them at high temperature. Accordingly, the electric resistance of the oxidized part increases, and current pours into the central unoxidized part. This makes it possible for a small amount of current to cause efficient laser oscillation. The all-optic switching memory elements currently under development consume a large amount of current and may offset the low power consumption that features the all-optic communication system. The newly developed switching memory element will be presented in the conference of the Institute of Electronics,Information and Communication Engineers.