June 30, 2006, Los Angeles, CA--Building on a series of recent breakthroughs in silicon photonics, researchers at the University of California at Los Angeles (UCLA) Henry Samueli School of Engineering and Applied Science have developed a novel approach to silicon devices that combines light amplification with a photovoltaic effect.
In a study presented at the 2006 International Optical Amplifiers and Applications Conference in Vancouver, BC, Canada, UCLA Engineering researchers report that not only can optical amplification in silicon be achieved with zero power consumption, but power can now be generated in the process. The team's research shows that silicon Raman amplifiers possess nonlinear photovoltaic properties, a phenomenon related to power generation in solar cells. In 2004, the same group at UCLA Engineering demonstrated the first silicon laser, a device that took advantage of Raman amplification.
"After dominating the electronics industry for decades, silicon is now on the verge of becoming the material of choice for the photonics industry, the traditional stronghold of today's semiconductors," said Bahram Jalali, the UCLA Engineering professor who led researcher Sasan Fathpour and graduate student Kevin Tsia in making the recent discovery.
The fundamental challenge in silicon photonics is the material stops being transparent at high optical intensities, making light unable to pass through. "In the past, two-photon absorption in silicon has resulted in significant loss for high power Raman amplifiers and lasers, reducing efficiency and necessitating complex mitigation schemes. UCLA Engineering's new development will enable recycling power that would otherwise be lost. In space and military laser systems, the impact of device efficiency on electrical power and thermal management is a prime consideration," said Dr. Robert R. Rice, senior scientist at Northrop Grumman Space Technology's Laser and Sensor Product Center.
The challenge of power dissipation in traditional silicon semiconductors already is so severe that it threatens to halt the continued advance of the technology described by Moore's law. Because the UCLA Engineering team's discovery creates an advantage in heat dissipation, it represents a new perspective.
"This discovery is a step forward and makes it much more likely that the photonics and electronics will converge. If they do, many applications that silicon photonics has promised will come to fruition," Jalali said.
For more information, see www.ucla.edu.