Photonic lasers - the quick guide

Photonics, also called optoelectronics, is a rapidly evolving field that combines optical and electronics phenomena into tiny lasers, optical sensors and high-brightness light-emitting diodes. The technology initially sparked an explosion in the fibre-optic communications market. More recently, research on lasers and other technologies is being driven by demand for faster computer chips, brighter and flatter displays and higher density optical disk drives.

What is it? | Where it fits in | The market | Where’s the buzz | Is there money in this?

What is it?

Photonics is the technology of capturing, generating and harnessing light and other types of radiant energy based on the photon, which is a unit of energy. The field includes the emission, deflection, amplification and detection of light by optical components and instruments, lasers, fibre optics and other systems and devices.

This may sound like something only Mr Spock from Star Trek would understand. And some of the hottest technologies in the labs, such as minuscule lasers, are indeed mind-boggling, including the fact that there are anywhere from 30 to 50 different ways to make a laser.

Lasers are core components in photonics-based products, including optical disk drives and glass-fibre-optic communications that transmit laser signals carrying voice and computer data at speeds potentially up to 40 gigabits (billions of bits) per second.

Take, for example, recent innovations at Stanford University, California, including a faster, more efficient laser for communications uses. The new laser is based on a photonic crystal (see photograph, top), a square layer cake of indium phosphide and indium gallium arsenide phosphide only 300 nanometres (millionths of a millimetre) thick. The material is etched to create an array of regularly spaced, 400-nanometre-wide holes throughout the cake. The areas without holes, or microcavities, trap light.

The laser is tiny: about 400,000 such lasers could fit within a chip one centimetre square. The technology trend is toward smaller chips that may be cheaper to make and easier to put into smaller electronic products.

The technology works when pulses of light are shined onto the photonic crystal. The energy from the light pumps causes the indium gallium arsenide phosphide layers - known as "quantum wells" - to emit light of a desired wavelength. The light then bounces around in the microcavities and back to the quantum wells, setting off a chain reaction of light emission from the crystal that produces a laser beam. The result: a laser that could speed up fibre-optic networks. The researchers who built the laser said that it can theoretically run faster than 100 gigabits per second, 2.5 times the communications industry goal of 40 gigabits per second.

Where it fits in

Optoelectronics devices work across a number of markets, and there is a trend toward convergence in these markets. One example is marrying photonics devices to traditional silicon devices, an area known as silicon photonics. Active players in this research are Intel Corp., Stanford, and the University of California at Santa Barbara (UCSB), the University of Southampton, and the US government's Defense Advanced Research Projects Agency (DARPA), which also is sponsoring University Optoelectronics Centers.

UCSB researchers recently developed a hybrid silicon evanescent laser by bonding optical layers directly to a silicon laser cavity. The researchers say that the performance of microelectronic systems will depend increasingly on the connections between chips and devices. As the systems get smaller, the current nature of these connections will limit their performance. But optical interconnections could solve that problem with a semiconductor laser that can be coupled fully with silicon-based microelectronics.

Stanford also has discovered that germanium can work with silicon. Most of the high-performance optoelectronics devices are made from unusual materials that are not compatible with silicon. But Stanford researchers have discovered that germanium, which is compatible with silicon, has properties that could make it an ideal material for a modulator that could boost the speed at which silicon chips output data.

The tiny modulator is only a concept now. It is basically a solid-state shutter that would break a laser beam into a stream of digital data, allowing for longer connections between chips that use light instead of electrical connections.

The market

 

One benefit of photonics is its almost limitless application: faster communications, brighter and flatter TV and other screens, medical imaging and other devices that could be less invasive to patients, biomedical or chemical sensors, and high-brightness LEDs for architectural lighting, industrial displays and automobiles that don't need replacement for years and that save energy.

 

The worldwide optoelectronics market in 2004 was $236 billion, up from $139 billion in 1997, according to the Optoelectronics Industry Development Association (OIDA), an industry group in Washington, DC. In 2004, computers had become the largest application area at 61 per cent, with consumer electronics second at 30 per cent.

 

While communications applications grew quickly from $14 billion in 1997 to $58 billion in 2000, too many competitors and too much manufacturing capacity caused the bubble to burst in 2001, and communications fell to merely 9 per cent of the total worldwide optoelectronics market in 2004. Communications is now back on track for growth, said Michael Lebby, executive director of the OIDA.

 

 

Newer areas like lasers and optical sensors are poised for growth as well, though their markets are small compared to flat-panel displays, which dominate the market in 2004.

 

Where's the buzz?

 

The broad spectrum of applications – medicine, lasers, imaging, consumer products, computers, and flat panel displays - has laboratories and companies pushing forward in technology and patents.

 

Major multinational companies including IBM Corp., and Osram Opto Semiconductors GmbH are conducting advanced photonics research. So, too, are research universities including the Massachusetts Institute of Technology in Cambridge, Massachusetts, Rensselaer Polytechnic Institute in New York, and Cambridge University in the UK. And recently, the International Photonics Commercialization Alliance was created between Canadian and US photonic organisations.

 

Activity is rising in Asia as well, where countries such as Taiwan are pushing flat-panel LCD displays, DVD drives and other products toward becoming commodity products.

 

 

In Japan, optoelectronics is heading toward a $1 trillion business, with a mix of medical, sensor, computer, lighting, memory, communications and other applications.

 

The number of patents is on the rise, with patents associated with devices made from indium phosphide rising from 2,309 in 1990 to 10,391 in 2003, according to US Patent and Trademark Office data.

But there is little cross-licensing in the field of photonics so far, the industry says, and there is a fair amount of patent litigation currently. Finisar Corporation of Sunnyvale, California, was awarded a patent in September that protects an invention covering circuitry and methods for monitoring optoelectronic devices such as optical transceivers. It subsequently sued Agilent Technologies, of Palo Alto, California, for patent infringement, seeking substantial damages for lost profits on sales of at least $1.1 billion.

Is there money in this?

Companies are taking several approaches to making money. European makers like Osram also are taking the innovation, high-margin approach. But the OIDA’s Lebby says companies can compete on high volumes as well by taking advantage of the close geographical tie with Eastern Europe, which has low-cost manufacturing and a highly educated labour force.

In the laser area, Southampton Photonics, a spin-out company from the University of Southampton, UK, said in mid-October that it intends to go public on the Alternative Investment Market of the London Stock Exchange. The company was spun out of the university's Optoelectronics Research Centre in 2000 with the largest-ever UK university start-up funding. Its fibre lasers are aimed at a $2.3-billion global market. One of the few photonics companies to go to the public market in several years, it is targeting a niche market in industrial lasers, although its lasers, some of which are powerful enough to cut one-inch steel, also could be used to mark fruit.

The Optical Research Centre at Southampton has several spin-outs in the local area, such as Mesophotonics Ltd. and Stratophase Ltd., both of which are developing innovative products with lasers.

While photonics devices and companies are gaining traction, there are technological, image and manufacturing issues to overcome. Tiny lasers are challenging to build and manufacture at reasonable cost, and with upwards of 50 different ways to make them, some standards are needed.

And some investors, burned by the communications bust, still run from the word "photonics". But federal funding from institutes like DARPA, which has backed research at Stanford and other photonics labs in the United States, as well as the National Science Foundation, at least assure funding for the earliest stages of cutting-edge technology development, such as lasers.