Take a look at your headphones: they already use a technology that could one day help push broadband speeds to an astonishing 400 Gbps — active noise cancellation.
A research team led by Xiang Liu at Bell Laboratories is exploring a technique called phase conjugation to dramatically increase data rates as global demand for faster broadband grows.
Active noise-cancelling headphones work by detecting unwanted sound and generating inverse signals to cancel the noise. The researchers propose applying a similar idea to fiber-optic communications.
All fiber-optic cables experience some degree of signal distortion and interference caused by the materials and the transmission medium itself. Today, overcoming that distortion typically requires amplifying the signal, which can introduce errors; when errors occur, additional corrective data must be sent to recover the original information.
Phase conjugation offers a clever alternative. The method involves transmitting two signals with opposite-phase properties through the same fiber. Where interference occurs, the signals interact so one effectively cancels the distortion of the other, preserving the intended information.
Using this approach, the researchers successfully transmitted data at 400 Gbps over 12,800 km of standard fiber-optic cable. That throughput is orders of magnitude higher than typical consumer broadband speeds and represents a major step forward for long-haul optical links.
Because phase conjugation reduces the impact of distortion when signals are amplified, it enables reliable transmission over much longer distances without the same level of error correction and retransmission. The result could be more consistent, higher-speed connectivity to remote and rural regions that today struggle with limited broadband options.
While more development and real-world testing are needed before phase conjugation becomes a standard feature in commercial networks, the technique demonstrates a promising path toward scaling optical bandwidth and extending the reach of ultra-high-speed internet.
Do you think using phase conjugation is a promising direction for the future of fiber optics?