Feeds

Caltech sends light on a one-way trip

Optical computing gets a small step closer

Build a business case: developing custom apps

A group of Caltech researchers is claiming what it describes as a key breakthrough in photonic computing: an optical diode using linear, rather than non-linear, materials.

The diode – or rather, components that mimic the function of the diode in the optical domain – is important to optical computing, because it helps isolate signals from each other. For example, it protects signals from interference from backscattered noise.

According to PhD scholar Liang Feng, the optical isolator – a device that allows light to travel in one direction only – is “something that scientists have been pursuing for 20 years”.

One way to isolate light is with magnets, but this isn’t feasible at the microscopic scale needed to build integrated optical chips capable of carrying out computing functions: the magnets need to be too big. The other is to use non-linear optical materials. This works well, but the researchers say non-linear materials are difficult to integrate with traditional silicon-based fabrication methods.

In their proof-of-concept paper, Non-reciprocal light propagation in a silicon photonic circuit, published in Science, the researchers say they have transmitted light in a symmetric mode in one direction, but in the other direction, the light changes to asymmetric mode. The paper is outlined here.

This isn’t actually “blocking” the light in the return direction – not in the way that a diode blocks an electrical signal in the “wrong” direction – but it means that the two optical signals don’t interact with each other.

The Caltech group built an 800nm x 200nm waveguide, and added materials with different reflective and refractive properties to break the symmetry of the light passing through the waveguide.

The next step for the researchers will be to take the proof-of-concept and create optical isolators suitable for integration onto integrated circuits. ®

Boost IT visibility and business value

More from The Register

next story
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
Flamewars in SPAAACE: cooler fires hint at energy efficiency
Experiment aboard ISS shows we should all chill out for cleaner engines
Brit amateur payload set to complete full circle around PLANET EARTH
Ultralight solar radio tracker in glorious 25,000km almost-space odyssey
NASA Mars rover FINALLY equals 1973 Soviet benchmark
Yet to surpass ancient Greek one, however
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
BEST BATTERY EVER: All lithium, all the time, plus a dash of carbon nano-stuff
We have found the Holy Grail (of batteries) - boffins
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.