Specialized switch that controls light can regulate flow of optical data at speed suitable to accelerate computers

Oct 09, 2013
The silicon ring is a fast and effective switch for a beam of light skimming close to its edge. Credit: 2013 A*STAR Institute of Microelectronics

Long-distance communication increasingly relies on networks of fiber-optic cables that carry data encoded in nimble beams of light. Conventional computer circuits, however, still use relatively sluggish electronic circuits to process this data.

Hong Cai of the A*STAR Institute of Microelectronics in Singapore and her co-workers have now developed a device that could help computers reach light speed. Their tiny mechanical system can switch a light signal on or off extremely quickly, potentially enabling all-optical computing and simplifying the interface between electronic and optical networks. "All-optical devices could enable a large number of components to be housed on a single chip," says Cai.

Various optical switching technologies already exist, including microelectromechanical systems (MEMS). These switches, however, take microseconds to flip from one state to another, far too slow for a computer application. Cai's device is a much smaller nanoelectromechanical system (NEMS) that can switch in billionths of a second, with virtually no data loss.

"NEMS optical switches offer the potential for fast switching speed, low optical loss and low power consumption. And, they are easily integrated in large-scale arrays without complex packaging techniques," says Cai.

The researchers etched their device from a thin sheet of silicon, forming a flexible ring 60 micrometers wide that is connected to a central pillar by four thin spokes. Two channels running through the underlying silicon skim past opposite edges of the ring; they act as waveguides for two beams of light. These channels pass no closer than 200 nanometers from the ring (see image).

When light carrying a signal passes through one of the channels, the light's electromagnetic field establishes resonant oscillations around the ring. This draws energy from the beam and prevents the data from travelling any further—the switch is effectively 'off'.

To flip the switch, a low-power beam of 10 milliwatts traveling along the other channel establishes a similar resonance that slightly warps the ring, bending its edges downwards by just a few nanometers. This warping motion changes the resonant frequency of the , preventing it from coupling to the signal beam and allowing the to continue unimpeded. Switching the signal on took just 43.5 nanoseconds, and the researchers observed a large difference in signal output between the 'on' and 'off' states.

"As such, a low-power optical signal can be used to modulate a high-power at high speed," says Cai. Her team is now working on integrating the devices into circuits.

Explore further: Precision gas sensor could fit on a chip

More information: Cai, H., et al. A nanoelectromechanical systems optical switch driven by optical gradient force, Applied Physics Letters 102, 023103 (2013). dx.doi.org/10.1063/1.4775674

add to favorites email to friend print save as pdf

Related Stories

Switching light on and off - with photons

Nov 09, 2011

(PhysOrg.com) -- Cornell researchers have demonstrated that the passage of a light beam through an optical fiber can be controlled by just a few photons of another light beam.

Graphene photodetector integrated into computer chip

Sep 16, 2013

The novel material graphene and its technological applications are studied at the Vienna University of Technology. Now scientists succeeded in combining graphene light detectors with semiconductor chips.

Recommended for you

New filter could advance terahertz data transmission

Feb 27, 2015

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

Feb 27, 2015

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

Precision gas sensor could fit on a chip

Feb 27, 2015

Using their expertise in silicon optics, Cornell engineers have miniaturized a light source in the elusive mid-infrared (mid-IR) spectrum, effectively squeezing the capabilities of a large, tabletop laser onto a 1-millimeter ...

A new X-ray microscope for nanoscale imaging

Feb 27, 2015

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

New research signals big future for quantum radar

Feb 26, 2015

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.