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Bell Lab Researchers Use Noise Cancelling Headphones Concept To Improve Fiber Optics

Question asked by Satya Swaroop Dash in #Coffee Room on May 27, 2013
Satya Swaroop Dash
Satya Swaroop Dash · May 27, 2013
Rank A3 - PRO
Every signal traveling through a transmission medium gathers noise and as the distance increases so does the noise. Conventional ways to reduce noise are good but what if we can use a pre-existing technology to improve the noise reduction process. You are well aware how noise cancelling headphones work - the microphone present in the headphones captures the ambient sounds and generates the inverse signal that cancels out the noise. Dr Xiang Liu of Bell Laboratories in New Jersey, USA took the above noise cancelling concept and applied it to networking. The team added the phase conjugate of the signal being transmitted through the fiber optic cable along with the actual signal. During the transmission noise will surely be added to the signal and also to its phase conjugate signal. So at the receiver’s end when both signals are superimposed the noise signals will cancel each other out and the original signal can be easily retrieved.

Sample Fiber Optic Image

The problem with sending a powerful signal is that the noise added to a signal is directly proportional to the signal power. So we often have to limit the power which means that the signals cannot travel to longer distances. Since the team does not have to worry about noise, they managed to send a signal of 400 Gbps down a distance of 12,800km optical fiber by using this method.

For a detailed report you may refer to their report in Nature Photonics.

Source: BBC Posted in: #Coffee Room

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