IBM has come up with a technology that could one day let different cores on a processor exchange signals with pulses of light, rather than electrons, a change that could lead to faster and far more energy efficient chips.
The device, known as a silicon Mach-Zehnder electro-optic modulator--converts electrical signals into pulses of light. The trick is that IBM's modulator is 100 or more times smaller than other small modulators produced by other labs. Eventually, IBM hopes the modulator could be integrated into chips.
Electrons in, photons out.
(Credit: IBM)Here's how it works. Electric pulses, the yellow dots, hit the modulator, which is also being hit with a constant beam of light from a laser. The modulator emits light pulses to correspond to the electrical pulses. In a sense, the modulator is substituting photons for electrons.
Since the beginning of the decade, several companies--Intel, Primarion, Luxtera, IBM--have been coming up with components that, ideally, will let chip designers replace wires in computers and ultimately chips with optical fiber. Wires radiate heat, a big problem, and the signals don't travel as fast as light pulses. (The research in this area is known as silicon photonics and optoelectronics.)
The problem with optical technology, however, is making it small. Optical components historically have been tricky to produce and tend to be fairly large. Computer makers need components that measure only a few millimeters on a side. The idea is to come up with a way to produce modulators, lasers, waveguides and other devices on silicon manufacturing lines.
Right now, it remains an open question when these products will come to market. Still, the plethora of prototypes is a strong indication that progress is moving along well.
In its quest to develop laser weapons, the Pentagon is aiming both high and low.
The sky-high plans for the Airborne Laser call for a squadron of 747s that would train chemically generated laser beams on ICBMs (intercontinental ballistic missiles) to knock out those missiles long before they become a threat to targets in the United States. A "lethality" test of that system is scheduled for 2009, though if past delays are any indication of future performance...
A solid-state laser does its thing under the watchful eye of a Northrop Grumman engineer. At its new Directed Energy Production Facility in Redondo Beach, Calif., the defense contractor aims to build a 100-kW device that can be used on the battlefield.
(Credit: Northrop Grumman)For a more down-to-earth system, look no further than a truck-mounted solid-state laser now in the early stages of development. Rather than intercontinental missiles, this system would protect ground troops from smaller projectiles including rockets, artillery rounds and mortar shells. Advantages that solid-state lasers have over their COIL (chemical oxygen iodine laser) counterparts include smaller size and lighter weight--there's a reason that the Airborne Laser requires a 747--and the avoidance of big doses of toxic materials. COIL systems pack a bigger punch, however.
The U.S. Army Space and Missile Defense Command has enlisted two defense sector heavyweights to vie with each other to produce the ruggedized beam control system, a key component of what will become the High Energy Laser Technology Demonstrator (HEL TD). Northrop Grumman this week said it received an $8 million, one-year contract to do that work, followed in about a month by Boeing's receipt of a $7 million deal to do the same. For both contractors, options could extend the programs to about $50 million.
The Space and Missile Defense Command is the lead agency for the Army's high-energy solid-state laser program, the next phase of which is to boost the power capability from 25 kW to 100 kW. (According to a report from the BBC earlier this year, a solid-state laser in a lab set a record by reaching 67 kW.)
But the laser engine itself is just one factor in a very challenging equation; what Boeing and Northrop Grumman will have to wrestle with is getting it to work when mounted on one of the Army's Heavy Expanded Mobility Tactical Trucks, or HEMTTs.
Meanwhile, elsewhere on the truck-mounted directed-energy beat, the Associated Press on Wednesday ran an in-depth story on the Active Denial System, which uses millimeter waves to blast human targets with a scorching--but nonlethal--sensation of heat. For months, the AP reports, military leaders have asked for the ADS, which is still in the prototype stage, to be deployed to Iraq to help quell civil disturbances, but the Pentagon, worried that the system could be seen as inhumane, has repeatedly said no.
If the Defense Department continues to stall for a more favorable moment, that may give Raytheon the opportunity to pitch its similar "Silent Guardian" system (it has one ready to go), the AP says.
Politics aside, directed-energy weapons still are in their infancy. As Thomas Killion, chief scientist of the Army, told News.com last month, "It's still a very hard technical problem. We are working hard to make this a reality--it's going to take some time."
Researchers at Intel this week are showing off an silicon modulator that can pass 40 gigabits of data in a second, a new record that indicates that fiber-inside-computers is really coming.
Still life of 40-gbps modulator
(Credit: Intel )A modulator is an component from the fiber optic industry. It essentially chops up light from a laser into blips that ultimately will be understood as 1s and 0s by a computer. Right now, computers (and chips) pass signals via electrons traveling along metal wires. Metal wires give off heat, which has created an energy crisis inside computer.
By contrast, fiber optics transmit data with photons, which are faster than electrons and don't give off heat. The catch? The components for creating a fiber network are historically big, expensive and finicky. Chip engineers often call producing fiber a black art.
For the past several years, Intel, Primarion, IBM and others have been coming up with ways to mass produce optical components on standard silicon manufacturing lines. There have been prototypes for modulators, lasers, and other parts. (We started writing about this in 2001.)
Intel first came out with a 1GHz silicon modulator in 2004. It then upped the speed to 10 gigabits per second a year later. This latest component passes 4 times as much data, uses less energy and is smaller. Thus, it might cost less too.
How does it work? Project leader Ansheng Liu describes it in his blog:
"The intensity of the light transmitted through the Mach-Zehnder interferometer is modulated by modulating the phase difference between the interferometer's two arms," he wrote. That clear? It transcends my Speed Racer level of scientific understanding, but I'll take his word for it.
Intel, among others, has projected that optical components may start getting integrated into computers toward the end of the decade. At first, optical parts will be separate chips. Later, optical parts will get integrated into chips. And ultimately that means faster cameras, MP3 players and computers.
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