Feeds

All-optical RAM to clear comms bottleneck

NTT shows off nanowatt optical memory

The Power of One Infographic

Japanese researchers are claiming a breakthrough in all-optical memory, one of the key bottlenecks remaining in the optical communications world.

The high throughput of optical communications systems brings its own problem: any function that can’t be performed in the optical domain demands an opto-electric conversion, creating a bottleneck in the system. This has put a premium on research into optical switching, amplification and signal regeneration.

Memory is a tough nut to crack, however: it demands that a photon’s state be captured, retained and read out – all without converting the signal back to electrons, and in a repeatable and cheap fashion.

The NTT researchers say they have created an ultra-low-power optical RAM using optical cavities that represent a 1 or 0 by either passing or blocking light. The memory cell uses a material based on an indium gallium arsenide strip buried in gallium arsenide.

It acts as a memory because the indium-gallium arsenide strip changes its refractive index when exposed to a laser. The light beam it’s trying to “remember” will be blocked or passed depending on the state of the strip. A second pulse of laser on the “control” strip reverses its state.

While it only retains state for about a microsecond, the researchers say that’s long enough for other system components to use the stored information (and four times the previous record for an all-optical memory). Importantly, they also say the optical cavity approach consumes very low power – according to the Nature Photonics abstract, 30 nW, which is “more than 300 times lower than the previous record”. ®

Bootnote: Proposals for optical memory have existed for a surprisingly long time. For example, this Wikipedia entry describes an approach using a loop of photo-emissive and photo-sensitive materials from the 1950s, as an attempt to solve the problems of memory speed in early computers. ®

Eight steps to building an HP BladeSystem

More from The Register

next story
Malaysian Airlines flight MH17 claimed lives of HIV/AIDS cure scientists
Researchers, advocates, health workers among those on shot-down plane
Forty-five years ago: FOOTPRINTS FOUND ON MOON
NASA won't be back any time soon, sadly
Mwa-ha-ha-ha! Eccentric billionaire Musk gets his PRIVATE SPACEPORT
In the Lone Star State, perhaps appropriately enough
MARS NEEDS OCEANS to support life - and so do exoplanets
Just being in the Goldilocks zone doesn't mean there'll be anyone to eat the porridge
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Diary note: Pluto's close-up is a year from … now!
New Horizons is less than a year from the dwarf planet
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
prev story

Whitepapers

Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.