FREE ENERGY
Another energy-related research project is under way at the University of California, Los Angeles. Bahram Jalali, a UCLA electrical engineering professor, has developed a process that enables silicon optical amplifiers to produce power that's normally wasted as heat (Fig. 4). In 2004, Jalali created the first silicon-based laser, a technology with significant potential in optical communication and other fields. Yet the device's high power consumption threatened to limit its potential.
Tackling the problem through research co-sponsored by DARPA and defense contractor Northrop Grumman, Jalali discovered that Raman optical amplifiers, the same basic technology that was used to create the silicon laser, possess nonlinear photovoltaic properties that permit them to recycle wasted optical energy.
"We showed a method that consumes zero electrical power," says Jalali. "In fact, we showed that we can also recover any optical power that was absorbed in silicon. In other words, the device has negative power dissipation." Utilizing the new approach, silicon lasers and optical amplifiers should be able to scale nicely to high power levels, he says.
High-power optical sources are very important to the military, notes Jalali. "They are needed in a number of systems, ranging from directed energy weapons to defense against heat-seeking missiles and the detection of biochemical warfare agents," he says.
Jalai also envisions multiple commercial applications, including high-speed, low-cost Ethernet optical modules within a few years. "A longer-term application is chip-to-chip interconnects where microprocessors, graphics processors, and memory chips communicate via optical signals resulting in higher performance," he adds.
A BETTER WAY?
The U.S. is often criticized for the way it sponsors the development of military technologies. "Most of the time, it's the government that comes up with certain requirements and then goes to the labs and asks for the new technologies," says Ostrove. The standard operating procedure calls for DARPA or other government agencies to send out a wish list, receive proposals, and then award grants to the successful bidders.
But other nations do it differently. Some, such as Japan and the E.U., create formal research planning commissions that unite government, industry, and academic leaders to evaluate and assign research projects to specific institutions. Yet despite such careful planning, these nations have contributed relatively little to military technology over the past several years. Could it be that the U.S.'s patchwork approach is better at selecting and nurturing new technologies? Ostrove thinks so.
"It may just be that that the secret to success lies in having a certain amount of chaos," he says.