# Synopsis: Smarter Pulse Shaping for Fiber Optics

Researchers propose a new way to eliminate the signal distortions in optical fibers that are caused by nonlinear effects.

To boost the capacity of optical fibers—the glass cables that carry digital information to more than two billion internet users—engineers encode information on many wavelengths. But this technology, known as wavelength division multiplexing, is limited in how fast it can send information because of interference between signals. Writing in Physical Review Letters, researchers propose a way to eliminate this cross talk and potentially raise the rate at which future fibers transmit data.

The new approach tackles the problem of optical nonlinearity in fibers, in which an intense light pulse alters the fiber’s index of refraction. Nonlinearity causes interactions between pulses carried at different wavelengths, producing distortions that lead to errors. Since the effects are mathematically complex, they are difficult to correct when the pulses arrive at their destination. And although optical fibers are only weakly nonlinear, the effect can be significant when pulses are transmitted at distances of several-hundred-kilometers or at rates in excess of 10 gigabits/second.

Jaroslaw Prilepsky at Aston University, UK, and his colleagues modeled the passage of light through an optical fiber using the nonlinear Schrödinger equation and found a set of signal waveforms that, according to this equation, behave like sinusoidal waves in a fiber with no nonlinearities. In principle, any light signal can be generated as sums of these specially shaped pulses. As a proof of concept, the authors simulated the transmission and sending of a sequence of signals along a 2000-kilometer fiber using their new strategy and showed that the signals arrived without distortion. – Jessica Thomas

### Announcements

More Announcements »

Optics

Gravitation

## Next Synopsis

Particles and Fields

## Related Articles

Optics

### Synopsis: The Helical Factor

An array of helical elements absorbs radiation of a certain frequency while casting no shadow in light over a range of other frequencies. Read More »

Optics

### Focus: Nanoscale Device Amplifies Fiber-Optic Signals

Researchers have demonstrated an amplifier for near-infrared light that is $20$ times more powerful than previous devices and small enough to fit on an integrated circuit. Read More »

Atomic and Molecular Physics

### Viewpoint: Making a Molecular Movie with X Rays

Femtosecond x-ray pulses image structural changes in a molecule. Read More »