Finally optical component makers dare to dream again

Iron-grey skies, driving rain and chilly north winds served up a gloomy backdrop for the 3000 and more hardy souls who made the trip to Glasgow in late September for the 31st European Conference on Optical Communications (ECOC). But this is 2005, and not the darkest days of the telecoms bust. If conditions were less than hospitable on the outside, the same could not be said for the busy halls of the Scottish Exhibition and Conference Centre, where upbeat exhibitors and delegates contributed to the most constructive, forward-looking ECOC since the telecoms industry went into freefall four years ago.

After 18 months of gradual recovery and careful repositioning, it seems that fiber-optic component and subsystem companies are daring to dream again, factoring long-term growth and credible opportunities back into their strategic thinking. That was certainly the line being pushed by Tom Hausken, lead analyst at US consultancy Strategies Unlimited. "Finally, after all these years, we see an uptick in [wireline] capital expenditure; this year it looks like it ll be up by 10 or 15%," he told delegates at KMI s European Conference on Optical Networking Markets, a pre-ECOC seminar in central Glasgow.

That uptick is significant because fiber-optic component revenues are tracking carrier capex, with sales of components in 2005 up significantly on 2004. Hausken added: "So far, it [component revenue] looks like it ll be up by about 13%. Expect steady, repeated growth of that kind in 2006."

Adding to that feelgood factor, the ECOC trade show saw the resurgence of several technologies initiated way back in the heady days of the photonics boom and now finally coming to fruition. For starters, Intel, US, announced that Fujitsu has adopted its full-band tunable laser for use in next-generation 300-pin tunable transponders. According to Bob Zona, director of marketing for Intel s optical-platform division, this deal is representative of the increasing demand for tunable lasers across the industry.

The tunable transponders will incorporate Fujitsu s lithium-niobate modulator and Intel s TTX19907 integrable tunable-laser assembly. Zona says that Intel has been working on design-ins with systems vendors over the last 12-18 months. Last year, the projects moved out of the qualification phase and into production, with Zona claiming that the technology is now "ready for primetime". One reason for the increased acceptance of tunable lasers, he says, is the big reduction in the price difference between tunable and fixed-wavelength lasers. Intel s TTX19900 C- and L-band thermally-tuned lasers are available at a unit cost of $2500. The lower cost was achieved, in part, by the use of innovative packaging to ease the manufacturing process.

Meanwhile, InP foundry and component maker Opnext exhibited a fully tunable 300-pin transponder, the TRV709A. Ed Cornejo, the US vendor s director of product marketing, also noted that the demand for tunable devices is on the up.

According to Cornejo, another technology that is increasing in popularity is 40 Gb/s, driven in part by new deployments of voice-over-IP and IPTV services. Opnext had its 40 Gb/s 300-pin transceiver on show. The device offers a power consumption of just 20 W, achieved using direct modulation of the laser to lower the cost and the power budget. Opnext s customers are now qualifying its 40 Gb/s products. "It s still a couple of years away in terms of real demand for deployment," Cornejo said. "It ll take price erosion before that happens."

Neil Weston, vice-president of sales and marketing at the Centre for Integrated Photonics (CIP), UK, reckons that the last year has seen a resurgence of interest in 40 Gb/s technologies. "The big component and systems houses are asking for 40 Gb/s devices, while a year ago they were concentrating on 10 Gb/s." At ECOC, CIP was showcasing its latest optical-networking components for 10 and 40 Gb/s applications. Its 2R regenerator, for example, enables the optical regeneration of 40 Gb/s signals. Based on a combination of silica-on-silicon planar waveguides and InP semiconductor optical amplifiers, the device compensates for attenuation, polarization-mode dispersion and other impairments that can cause big headaches at ultra-high-speed data rates.

Clearly, with many of the 40 Gb/s technology issues now solved, it might not be too long before 40 Gb/s platforms - or indeed advanced devices such as tunable lasers - really make their mark in optical networks.

Hitachi-backed Opnext also revealed details of three new laser diode products for applications ranging from barcode scanning to medical equipment, while in the technical conference its researchers detailed a new short-cavity distributed Bragg reflector laser that should lead to smaller 10 Gb/s modules. The developmental 1310 nm edge-emitter is based on InGaAlAs technology.

Long-wavelength lasers of the vertically-emitting kind provided another talking point in Glasgow, as Danish company Alight announced that it had acquired the dilute-nitride VCSEL technology previously developed and owned by Infineon Technologies. Alight has already begun integrating the structures with its own proprietary photonic bandgap approach, which should result in high-power singlemode VCSELs emitting at the longer wavelengths that are crucial for long-distance transmission of data over fiber. Alight is aiming to manufacture the devices commercially using an MBE reactor installed at an unspecified foundry location.

Among the other companies to be showcasing long-wavelength VCSELs was Korean chipmaker RayCan, whose 1550 nm and 1310 nm sources are based on InP. The company has traditionally served only domestic customers, but is now planning to sell its VCSELs internationally.

In the technical session on semiconductor laser diodes, research at the Japanese company NTT showed how doping an InP-based buried heterostructure device with ruthenium instead of iron improved some operating characteristics. Doping with ruthenium reduces interdiffusion between the doped and active layers, improving the crystal quality of the quantum wells. This resulted in higher output power, especially at elevated temperatures, said the NTT team.

Meanwhile, researchers at Germany s Heinrich Hertz Institute (HHI) described a "curved stripe" 1550 nm distributed feedback laser that allowed uncooled 10 Gb/s operation at 90 °C in a high-yielding process. HHI was also involved in the manufacture of a quantum dot VCSEL structure designed by NL Nanosemiconductor that had a threshold current of just 2000 μA - described as "thresholdless" by the research team. NL Nanosemiconductor believes that the 1300 nm lasers could be useful for 40 Gb/s datacom applications, which it expects to see deployed widely in around five years.

But perhaps the most encouraging aspect of this year s ECOC was this: all of the new product activity, along with the upbeat projections, suggests that ECOC 2006 in Cannes will see the optical communications industry finally freed from its downturn nightmares.