Tag: xiang zhang

Graphene modulator means 3D film download in seconds

Scientists have found tiny optical devices using wonder material graphene could soon be used to reach download times “up to ten times faster” than currently seen.

Modulators are used in data communications to control the speed at which data packets are transmitted, with faster data pulses meaning greater volumes of information can be sent out.

Now scientists led by UC Berkeley engineering professor Xiang Zhang have devised an optical device based on graphene to switch light on and off as an “incredibly compact modulator”, which the scientists claim is the world’s smallest.

According to the scientists this means it will be possible to “significantly enhance our capabilities in ultrafast optical communication and computing”.

This could mean allowing to stream cutting edge content such as 3D movies onto your phone in a matter of seconds in the near future the scientists.

It is yet another surprising use for the material developed by researchers at the University of Manchester following the discovery of its properties after messing around with some sellotape, perhaps the most ingenious use of sticky-back plastic since Blue Peter showed kids how to create a high-street level Tracy Island from household goods packaging in the mid nineties.

Electric charges were applied to a sheet of graphene on top of a silicon ‘waveguide’, with the voltage running through the graphene changing the materials transparency and therefore abiliity to turn light on and off to function as a modulator.

This very basically works by passing many electrons elctrons through the graphene enabling photons to be absorbed and thus rendering the material opaque, or passing a negative voltage through can cause the drawing out of electrons and therefore leaving the material transparent and turning the light ‘on’.

The researchers were able to achieve a modulation speed of one gigahertz, though they believe that 500 gighertz could possibly be reached on a single modulator. 

In the past attempts to use optics rather than electricity have been hampered due to difficulties in implementing bulky optics onto computer chips, as light waves are “less agile” in tight spaces comparatively and so are mainly used in large scale devices such as fibre optics.

However they are among other things able to carry data packets more quickly, and graphene based devices could get round these problems, shrinking the devices down to 25 microns, much smaller than some commercial modulators which can be as big as a few square millimetres.

In fact the scientists say that the graphite used in one pencil is the equivalent of one billion modulators worth of graphene.

The researchers believe that this means instead of broadband it will be possible to achieve the rather more hyperbolic “extremeband”, and hope to see industrial applications of the new device in the “next few years”.