Want High Speed Internet? Go Organic!

Author: Karuna Meda
Institution:  University of Pennsylvania

With the number of internet users going up daily, there is an increasing demand for high speed and reliable internet access. Current telecommunications networks must convert optical signals to electrical signals, a somewhat inefficient process. An international team of researchers from Lehigh University, University of Karlsruhe in Germany, Ghent University in Belgium and Swiss Federal Institute of Technology in Zurich say that a full optical pathway could provide a tremendous boost to data processing. They are getting closer to this goal,by going organic! They have discovered an organic silicon material, of which a description was published on the Nature Photonics website on March 15th, with unprecedented optical quality.

Ivan Biaggio, a member of the team and associate professor of physics at Lehigh University, uses the model of snowflakes deposited between two bricks on a wintry day to explain the optical circuit in which the silicon material is integrated. The material consists of small organic materials that are able to uniformly fill the slots between waveguides or gaps where incoming light propagates. "By filling the slot," say Biaggio and his collaborators, "the molecules add an ultra-fast all-optical switching capability to silicon circuitry, creating a new ability to perform the light-to-light interactions necessary for data processing in all-optical networks."

The organic molecule used is called DDMEBT and is capable of condensing from its vapor phase to a bulky material. Furthermore, it has 1,000 times the non-linearity of silica glass. Another group member from Lehigh University, Bweh Esembeson, says that the combination of high, off-resonant bulk nonlinearity and large-scale homogeneity of this material is unique and rare. However, there are some drawbacks. Baggio says, "We need higher-speed switching to achieve a higher bit rate. Organic materials can do this, but they are not terribly good for building waveguides that control propagation of tightly confined light beams." Thus, in order to overcome this, the researchers covered silicon waveguides with DDMEBT to create silicon organic hybrid devices.

The results of the tests are indeed exciting,the device is able to extract every fourth bit of a 170-gigabit-per-second telecommunications data stream and to convert the single channel to multiple signals at a rate of 42.7 gigabits per second!

"To the best of our knowledge, this is the first time that nonlinear SOH [silicon-organic hybrid] slot waveguides were used in high-speed optical communication systems. We believe that there is still a large potential for improving the conversion efficiency and the signal quality."

The organic revolution is clearly impacting all aspects of our life; organic internet, here we come!