Hot technologies coming of age

06 Jan 2005

To celebrate the start of 2005, here's our pick of three innovative technologies set to light up the year ahead. In each case, we describe their recent achievements and potential future impact.

From Opto & Laser Europe January 2005

OLED DISPLAYS The Dream
An active-matrix full-colour display, made from organic light-emitting materials, that challenges the dominance of LCDs.

Current Status
Passive-matrix OLED displays are now starting to find their first applications in clam-shell style mobile phones, car dashboards and music players, but the technology could potentially do much more.

"The first products are not very exciting in many ways because they do not exploit the flexibility of the technology," Hermann Schenk of materials specialist Covion told OLE. "What we are now seeing is that the active-matrix technology - a more advanced technology that uses thin-film transistor backplanes - is beginning to enter the market."

One of the most important highlights of 2004 was Sony's announcement in September that it was starting volume manufacture of active-matrix OLED displays for use in its hand-held PDA (CLIE PEG-VZ90; see OLE November 2004, p5). "The real message sent by Sony to the market is that the manufacturing and design issues of active-matrix technology for OLED can be overcome," said Schenk. "The near-term future is really in applications where you want to display video information at close distances of up to 1 m from the user's eyes."

However, in the long term, OLED technology may not be confined to the world of personal electronics. The latest demonstrations are now able to offer the image quality of a cathode-ray-tube display in a flat-screen format. Seiko Epson of Japan unveiled the world's first 40 inch colour OLED TV at the 2004 Society for Information Display symposium in Seattle, US.

Future Challenges
Despite a series of technology breakthroughs, factors such as operational lifetime and cost of manufacture remain a concern. "The basic inventions have been made and it is now about improving the silicon processing so that OLEDs are stable enough to deliver consistent quality," commented Schenk. "Materials need to improve to get real market penetration in terms of lifetime."

Timeline
Throughout the next couple of years, it is likely that the main applications for OLED technology will continue to be in the personal electronics market. "Big companies like Samsung SDI are scaling up to be ready to supply to the market at around the turn of the year 2005/2006," said Schenk.

SILICON PHOTONICS The Dream
Silicon "superchips" that integrate electronic and optical circuitry.

Current Status
There is no doubt that 2004 represents a turning point in the development of silicon photonics. In February, Intel, the US computer-chip expert, reported a high-speed silicon (1 GHz) optical modulator.

Then, in November, scientists at the University of California, Los Angeles (UCLA), US, made the headlines when they demonstrated the world's first silicon laser - a silicon waveguide that uses the Raman effect and emits picosecond pulses at 1.68 μm. Ultimately, such devices could be integrated into electronics to create powerful "one-chip solutions".

"If you open an optical module today, you will see two types of components in there. There is a laser, an amplifier, or a modulator chip that is made in GaAs or InP, and then there are the electronic ICs that are made of silicon," Bahram Jalali of UCLA told OLE. "The first silicon photonic products will be single-chip, all-silicon versions of these products." As well as Intel expressing interest in silicon photonics, the semiconductor specialist STMicroelectronics has recently demonstrated silicon LEDs that emit green light.

Future Challenges
Perhaps the biggest challenges facing silicon photonics are related to market acceptance and demand. "The market size is still too small to justify integrated solutions," commented Jalali. "If volume is low, the cost per chip will be high and no-one will buy it. For silicon photonics to "fly", we need to see the market for optical products improve significantly."

Timeline
According to Jalali, it may only be a few years before the first silicon photonic devices start to hit the market. "I think we will see breakthroughs in 2005 with commercial deployment appearing in 2007," he told OLE. "Examples of these include amplifiers, optical modulators and Raman lasers with their driver and control circuitry integrated onto the same chip."

FIBRE LASERS The Dream
A cost-effective laser that not only displaces incumbent technology in industrial applications, but opens up new markets.

Current Status
The fibre laser has long been touted as a source offering efficient operation, high beam-quality and maintenance-free operation. The big issue now is living up to these expectations.

In the current market, fibre laser development appears to fall into three camps: high-power continuous-wave (CW), pulsed and ultrafast sources. Over the past few years, many companies have emerged and firms such as SPI (UK) and IPG Photonics (US) are now offering kilowatt-class systems for industrial applications. "The exciting thing is that these companies are now starting to see traction and adoption by the end-user," Andrew Brown, Aculight's director of business development told OLE. "Fibre lasers can provide multi-kilowatt output with a near-diffraction-limited beam quality, but the technology still has to prove itself. We have to be delivering lasers to the end-users that make a difference either in terms of better performance, cost or reliability."

Future Challenges
The clear goal for fibre lasers is to penetrate industrial applications. However, developers still have some challenges to overcome and issues to think about.

Top of this list is cost. Fibre lasers have to be cost-competitive with sources such as the CO₂ laser or the Nd:YAG laser to be adopted by industrial applications where the bottom line is crucial. "It's not just the price of the laser, it's the overall cost over the entire lifetime of the product," said Brown. "Reduced power consumption and cost of infrastructure are also significant. I think that these will be some of the metrics people will be looking at over the next year."

The pump diodes used in high-power CW fibre lasers account for a significant percentage of the cost of the overall system. Brown believes that improved high-brightness, high-power, lower-cost diodes are a future technology worth investing in.

Another issue is the fibres themselves. All of the high-power CW systems have used ytterbium-doped fibres and emit between 1,040 and 1,080 nm. According to Brown, continued development of fibre will provide fundamental laser sources at new wavelengths and a means to access additional wavelength regions.

"People are working on 1.5 and 2 μm as well as polarization-maintaining fibres," Brown said. "Aculight has also got CW fibre-lasers pumping single-frequency tunable multi-watt-level sources in the mid-infrared for sensing applications. We have also just recently made 60 W of green light."

Timeline
As more and more applications begin to adopt fibre-laser technology and costs begin to fall, 2005 could finally be the year in which fibre lasers gain a foothold in industrial applications. "Fibre lasers could take market share away from diode-pumped solid-state lasers," said Brown. "That might be a high repetition-rate Q-switched vanadate laser or a tens-of-watts laser for marking applications."

Overall, it is likely that 2005 will be a good year for the fibre laser. "There is a great deal of room in the market for lots of other companies," Brown concluded. "I think that there are many factors converging, whether it be on the market, technology or commercial front. They are definitely coming together to turn this into something that is real." If this is true, it is likely there will be more news of fibre laser sales and installations over the next year.