It is thought that rogue waves are a nonlinear, perhaps chaotic, phenomenon, able to develop suddenly from seemingly innocuous normal waves. While the study of rogue waves has focused on oceanic systems and water-based models, light waves traveling in optical fibers obey very similar mathematics to water waves traveling in the open ocean, making it easier to study them in a laboratory environment.

Still, detecting a rogue wave is like finding a needle in a haystack. The wave is a solitary event that occurs rarely, and, to make matters worse, the timing of its occurrence is entirely random. But using a novel detection method they developed, the UCLA research group was able to not only capture optical rogue waves but to measure their statistical properties as well.

They found that, similar to freak waves in the ocean, optical rogue waves obey "L-shaped" statistics - a type of distribution in which the heights of most waves are tightly clustered around a small value but where large outliers also occur. While these occurrences are rare, their probability is much larger than predicted by conventional (so-called normal or Gaussian) statistics.

"This discovery is the first observation of man-made rogue waves reported in scientific literature, but its implications go beyond just physics," said Bahram Jalali, UCLA professor of electrical engineering and the researcher group leader. "For example, rare but extreme events, popularly known as "black swans," also occur in financial markets with spectacular consequences. Our observations may help develop mathematical models that can identify the conditions that lead to such events."

Co-authors on the Nature paper include UCLA Engineering researchers Claus Ropers and Prakash Koonath.

The research was funded by the Defense Advanced Research Projects Agency (DARPA), the central research and development organization for the U.S. Department of Defense.

The UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to seven multimillion-dollar interdisciplinary research centers in space exploration, wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies. For more information, visit www.engineer.ucla.edu.