22 Feb 2008
Ireland's economic growth was dramatic enough to earn the country the nickname of the Celtic Tiger and the photonics industry has played a strong role in this expansion. Tim Hayes went to Cork to see the innovations and technical developments that are being made there.
The Irish economy features a high level of exports and a strong presence in manufacturing, medical devices, electronics and aerospace. This combination suggests a healthy laser and photonics sector, but the domination of exports means that the photonics industry lacks a strong domestic dimension. As Kevin Donnelly of the Enterprise Ireland development agency said: "How do you grow an Irish photonics industry when there's no single large company to gravitate around? How do you encourage a technology sector without a substantial domestic market?"
One tactic is to support universities and third-level (ie. post-high school) colleges. In recent years a number of start-ups have emerged from the university sector, but here too Donnelly faces a challenge. "The number of people wanting to study science and engineering is dropping. We need to double the number of technical graduates by 2013 otherwise Ireland will have a problem."
Donnelly's strategy is one of persistent encouragement. "What funding agencies can do is to encourage people to do the right things. Enterprise Ireland supports applied research rather than pure science, and we are a business development agency rather than programme managers," he explained. "Programme management is always political, involving priorities and levels of importance. Project funding stands a much better chance of seeing people work on things that they want to be working on."
Firecomms: VCSELs and RCLEDs
Firecomms was spun out from Cork's Tyndall National Institute in 2001, based on research into the manufacture of high-speed LEDs and vertical-cavity surface emitting lasers (VCSELs). It manufactures devices based on AlGaInP and InP, leveraging these materials to devices that emit visible light.
The company produces what is said to be the only red/visible VCSEL in production, operating at 650–690 nm rather than the 850 nm of most commercial VCSELs. A unique epitaxial design and special growth and processing techniques allow the VCSEL to operate at speeds above 3.2 Gbit/s.
Another Firecomms product is a red resonant cavity light emitting diode (RCLED) able to operate at up to 400 Mbit/s, said to be eight times faster than conventional LEDs. These RCLEDs are used with polymer optical fibre (POF) to replace copper cables in higher-volume markets, such as home and car networks, where glass fibre is too expensive to terminate, and copper is heavy and sensitive to electromagnetic interference.
Compared with other solutions, POF has a substantially lower installed cost, is not sensitive to electromagnetic interference, is easy to terminate and is lightweight. "POF has been around a long time for illumination applications and in basic industrial network times faster than that. POF gives high bandwidth without interference from electrical sources in the vicinity. And 650 nm is the sweet spot for POF attenuation."
One target market is automotive, and the Media Oriented System Transport networking standard for interconnecting the growing number of multimedia components in vehicles. This is a bus technology intended to be carried on an optical fibre bearer, exploiting the higher bit rates that the mater-ial can provide. Firecomms has developed an automotive-grade RCLED able to operate from –40 to 95 °C through epitaxial design of the RCLED and optical design of the transparent plastic encapsulated package.
Firecomms has also developed the OptoLock, a plugless fibre-optic transceiver providing instant termination of bare POF that simplifies the connection of devices in communications and infotainment networks. "In the near future, even DIY enthusiasts setting up home-video systems will be buying plastic fibre-optical cable by the metre, cutting and terminating it in OptoLock with just a basic blade," O'Mahoney predicted. "OptoLock makes it possible to install fibre in any low-cost home environment in seconds, and it requires no more skill than speaker wires do today."
Nualight: specialized lighting
Founded in 2005, Nualight is built on a combination of in-house expertise, supported by collaborative research at Tyndall and assistance from Enterprise Ireland. The firm manufactures energy-efficient LED lighting for grocery and retail outlets, based on the company's chip-level understanding of LED sources. "We're the only company focusing on this niche," commented managing director Liam Kelly. "We pride ourselves on being a one-stop shop specializing in digital lighting, and are the only company focused on the grocery trade and temperature-control applications. That closeness to the users helps us to break new ground."
The company's core expertise in junction temperature, thermal design and optical design of LEDs is applied in grocery illumination for freezer doors, undershelf and other lighting locations. Nualight's patents cover optical and heat-transmitting functions of illumination for these applications, along with temperature-controlled display cases and fibre coupling.
"Lighting is critical for the sales experience," pointed out Paul Kelly, the company's sales and marketing director. "Trials say that a 20% increase in sales is possible through careful changes to the lighting, and swapping five appliance doors over to LEDs can save a applications of perhaps 1–50 Mbit/s," said Declan O'Mahoney, Firecomms chief executive officer. "We make POF operate eight or 10 tonne of CO2 per annum for the full 10-year projected lifetime of the case. US retailers are under pressure to cut their energy use, since 58% of grocery energy used is in refrigeration, and 70% in temperature-controlled environments."
In such a specialized niche, Nualight needs specialized knowledge. Its stakeholders include architects, retailers and energy experts, as well as optical scientists, to understand the subtleties of the market. In Europe for example, equipment tends to be replaced after 4–5 years but in the US it can be left in place for more than a decade, so retrofitting is a key market requirement.
The company's knowledge of LED technology allows it to supply customers with products designed to meet their needs. "Each application is different, and customers want a choice of options in terms of illumination, styling and design. and by 2010 every retailer will use this technology."
SensL: low-light detection
SensL is an emerging player in the low-level-light detection market. SensL provides detector solutions based on the company's core technology of sensitive silicon photodiodes. "We manufacture solid-state silicon photomultipliers, which can replace standard photomultipliers in many applications," said Carl Jackson, the company's chief technical officer. At the core of each detector is a low-light sensing silicon photodiode capable of converting single photons into a measurable output signal. SensL uses dedicated fabrication processes to manufacture these sensors to provide the highest degree of sensitivity and device uniformity, using silicon CMOS processing techniques developed in-house.
"This is an enabling technology," said Jackson. "For applications where you previously had to use a photomultiplier tube (PMT), now you have a silicon alternative. That opens up not just replacement markets but new ones too, such as biomedical imaging, homeland security applications, nuclear medicine, and inspection and testing. It's a driver for new applications."
SensL's detectors offer several benefits including a small form factor, high detection efficiency and operating voltages of 30–50 V compared with PMT detectors, which typically use hundreds or thousands of volts. "Silicon diodes can detect a single photon and turn it into measurable current, and our devices can tell the difference between 1, 2, 3 or 4 photons," explained Jackson.
The company also sells photon counting detectors, high-resolution modules, and low-light detection educator packs – an entry-level lecture and laboratory series for academics looking to launch a training module in low-light sensing or semiconductor device physics. They also suit OEMs looking for a rapid learning curve on the technologies involved.
SensL's growth plans have led to the establishment of SensL Inc in California, headed by Joe O'Keeffe, SensL's chief executive officer. Jackson expects the US office to play a significant role in the company's future. "The US is a large emerging market, not least since US customers tend to be early adopters of new technologies," he commented. "We believe that the US is likely to account for 50% of our business in the long term."
Epi-Light: biophotonics growth
Serving the growing biophotonics sector, Epi-Light develops LED illumination systems for life-science applications, including pharmaceuticals, biotechnology and medical devices. The company's Exci-Light biofluorescence illuminator was launched in October 2007, and combines high-brightness LEDs with very narrow spectral output in a large uniform beam, making it suitable for fluorescence imaging applications that require speed and high sensitivity.
"Pharmaceutical equipment is a conservative business compared to, say, telecoms," commented Peter O'Brien, chief executive officer. "The markets are hundreds of units per annum and development times are long. But once technology is validated, it's difficult for customers to change."
According to Epi-Light, its UV-365-LEDs are the brightest and most compact single source UV LED illuminators on the market. To achieve this, the company uses a patented technique that produces a high density of LEDs on an aluminium substrate with integrated heat sink, via a metal MEMS process. "We use the latest semiconductor technology, precision optics and thermal management components to produce an illuminator superior to traditional UV lighting solutions," said O'Brien. "The added value comes from understanding issues like packaging and thermal control in these specific applications and not just selling a catalogue product."
Compared with some of the other photonics companies in Cork, Epi-Light currently operates on a smaller scale. Based in the Rubicon Centre, an incubation hub for spin-outs operated by Cork Institute of Technology, the company currently employs only two full-time people. "The danger for start-ups is that you start to swim in the technology and never get properly involved in the commercial aspects," commented O'Brien. "Our technology and IP are now in Nualight's flexibility and research has made our product very configurable," said Kelly. "This is not a catalogue sale, and changing to LEDs affects a company's installation and maintenance procedures. LEDs are more efficient, but other factors such as housings and fittings are closely involved. Payback can come in two years, but products are coming that will drive that down further, place, and we anticipate a sales and marketing push in 2008. But for now, my customers are my investors."
Tyndall Institute: applied research
The Tyndall Institute's research not only underpins many local companies, but also means that around one third of Ireland's photonics researchers operate in the region. Guillaume Huyet of Tyndall's Photonic Device Dynamics Group says that he's close to almost everyone he needs to know.
"Our research aims to understand the dynamics of novel semiconductor materials and devices," said Huyet. "Current work focuses on the properties of quantum dot materials and devices, broad-area lasers and the dynamics of bistable systems."
Quantum dots are man-made nano-structures where the motion of the electrons and holes is confined in all three spatial dimensions. "We have recently studied the properties of quantum dot semiconductor lasers under optical injection from a singlemode semiconductor laser," said Huyet. "We observed an enhanced stability that allowed us to investigate the appearance of single- and multiple-excitable pulses at one boundary of the locking region."
Elsewhere in the 200-year-old listed building that houses the Institute, Brian Corbett and his Photonic Sources Group design, fabricate and characterize III–V based photonic sources, aiming to improve the efficiency of solid-state lighting based on gallium nitride. "We are developing new high reflectivity, low resistance contact technologies and device structures for ultrahigh light extraction," he explained. "These devices are also attractive for low-cost, high-speed, high-temperature communication."
Another area of study is VCSELs, attractive for many applications where power consumption is critical at specific wavelengths. "We study these devices and the related resonant cavity LED in order to improve the temperature, power, wavelength and fibre-coupling performance," Corbett said. "We produce laser diodes with a wide range of wavelengths from 650 to 1600 nm."
Tyndall's success is a reflection of Enterprise Ireland's strategy for industrial collaboration. "Government money can be used to push people across borders, not simply by funding a laboratory, but by pushing people together and networking," explained Donnelly. "That's what Tyndall does."
Companies such as Firecomms then reap the benefits of the local approach. "Enterprise Ireland is not in the business of supporting competitors, whereas VCs may well see the benefit of pitting companies against each other," commented O'Mahoney. "Yes, it can take longer to get things off the ground here and everything is geared to export, which makes the level of risk longer and harder. But in return, the win is fantastic."
Thanks to Kevin Donnelly and Mort O'Connor at Enterprise Ireland.
• This article originally appeared in the February 2008 issue of Optics & Laser Europe magazine.
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