 |
|
|
 |
|
Ultrafast Parametric Signal Processing  Present and future networks are characterized by growing gap between the ability to transmit and process high-speed signals: while high-capacity links commonly carry Terabit-scale traffic, real-time processing rates are in Gbps range – a staggering, three orders of magnitude gap. Faced with an arbitrary-rate, arbitrary-format bit stream, one can choose to process data either off-line (capture-and-dump, process-later) or in real time. The Photonics System group led by Prof. Radic is addressing this challenge by developing new photonics preprocessor, a key part of “all-the-data-all-the-time” Terabit scalable technology. The new processor copies ultrawideband signal onto multiple spectral replicas and simultaneously samples all colors to generate low-rate streams compatible with conventional electronics. The technology introduces new functional blocks capable of multicasting more than forty simultaneous channels, 10THz-wide sampling and microsecond-scale delays. The group has recently demonstrated first real-time sampling of 320Gbps channel, setting three new records in the process. The effort, part of advanced DARPA program on parametric processing, has recently led to first multicolored sampling by a single parametric gate.
In one of the more exciting prospects of this research, the flow of the new processor can be reversed in order to accomplish ultrafast synthesis, allowing one to perform arbitrary channel generation at Terabit scale. |
Nanowires and Photovoltaics Two sets of ECE researchers believe that nanowires could hold the key to efficient solar energy. One team - led by professors Paul Yu and Edward Yu (above) - have demonstrated a way to increase the efficiency with which sunlight can be converted to electricity by using nanowires to extend an electrode into the polymer material of a photovoltaic cell. Specifically, they created experimental solar cells spiked with indium phosphide (InP) nanowires, which serve as electron superhighways, carrying electrons kicked loose by photons of light directly to the device`s electron-attracting electrode. In a test, electric current increased by six to seven orders of magnitude compared to the device without the nanowire.
In separate research also published in Nano Letters, professor Deli Wang outlined why the large surface areas, small volumes and short lengths of nanowires make them extremely sensitive photodetectors - much more so than larger photodetectors made from the same materials. Building on theoretical work done by fellow ECE professor Peter Asbeck, Wang fabricated and characterized ultraviolet photodetectors made from zinc oxide nanowires with diameters of 150 to 300 nanometers and lengths ranging from 10 to 15 micrometers. The result: short pulses of UV light were detected on time scales in the nanosecond range, combined with one of the highest internal photoconductive gains
ever reported. Says Wang: "These results are encouraging and suggest a bright future for nanowire photodetectors." |
Most Complex Silicon Phased Array Chip in the World Developed at UC San Diego A team led by professor Gabriel Rebeiz has developed the world`s most complex "phased array", or radio frequency integrated circuit. It`s the first 6-element phased array chip that can send at 30-50 Hz, and its size - just 3.2 by 2.6 square millimeters - is fraction of today`s billboard-sized phased arrays used by the military. The compact beamforming chip may enable a breakthrough in size, weight, performance and cost of next-generation phased arrays for millimeter-wave military sensor and communication systems. "DARPA has funded us to try to get everything on a single silicon chip, which would reduce the cost of phased arrays tremendously," says Rebeiz. "In large quantities, this new chip would cost a few dollars to manufacture." The chip - the UCSD DARPA Smart Q-Band 4x4 Array Transmitter - is strictly a transmitter, but the researchers are working on a chip that is also a receiver. In addition to its potential use in defense satellite communication and radar systems, the chip`s design will likely spill over into commercial applications, such as automotive satellite systems for direct broadcast TV, and new methods for high-speed wireless data transfer. Meantime, Rebeiz is working with professor Ian Galton and ECE chair Larry Larson on a project funded by Intel and a UC Discovery Grant to create silicon CMOS phased array chips that could be embedded into laptops and serve as high-speed data transfer tools. |
Slowing Light, Faster Development of Optics Slowing light - something that college physics textbooks don`t even mention - could enable the transport of information ptically rather than with wires. And electrical engineers led by professor Shayan Mookherjea are pushing the technology one step closer to a day when slowing light could significantly enhance computer performance and lower the power required by computer systems. "We`re opening a window between optical localization research - traditionally the domain of physicists - and research in optical interconnects and novel waveguides, where electrical engineers are leading the way," says Mookherjea, whose work was featured in the journal Nature Photonics. "The fact that the slowing of light occurs together with localization opens the door for more research in this area of photonics." Using Calit2`s Nano3 facility, Mookherjea`s team fabricated a slow-wave optical waveguide in a silicon-on-insulator chip. Ensuing research demonstrated for the first time that light can be localized within the chip-scale waveguide. |
A Search Engine with Ears Imagine a music search engine that asks you to type in words like "acoustic guitars" or "electronica with female vocals" and then returns songs that fit. Professor Gert Lanckriet is leading a project to build just such a "Google for music," and he`s building it on algorithms based on audio signal processing and statistical modeling. The automated song labeler, dubbed a "computer audition system," is capable of annotating an unlimited number of ongs with words that describe how the songs actually sound. A search for "blues songs with tambourines" will return famous and obscure songs alike. Of course, the songs have to be annotated before they can be ndexed by the search engine. To help get lesser-known music into the system, the team is setting up a Web site where bands can upload their own songs for annotation. Graduate students have also developed a eries of Web-based video games that lead players to label songs with words, and publicized the games on Facebook. Says Lanckriet, who received funding from the von Liebig Center to take his search engine closer to commercialization: "While the games are crucial for our research and our search engine, they are also a lot of fun and socially intense." |
Interacting with Industry
 One San Diego company, Linkabit, founded by UCSD professor Irwin Jacobs, has spawned more than 100 communications firms, and they are among the many corporations recruiting students for internships and jobs. They fund project-based courses and come to campus for information days and recruiting fairs. |
Interested in Research
 At UC San Diego, you don’t have to wait until graduate school. You can do research alongside faculty, postdoctoral researchers, grad students and even researchers from industry. Lab research is integrated into the curriculum, and students can work in the school’s one-of-a-kind labs and research centers. |
|
|
|
|
|
