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12 June 2008


Infinera introduces passive PICs in new optical line system

At next week’s NXTcomm08 event in Las Vegas, Infinera Corp of Sunnyvale, CA, USA is unveiling its first major new product since the launch of its DTN, a flexible ROADM (reconfigurable optical add-drop multiplexer) and DWDM (dense wavelength division multiplexing) digital optical network system for long-haul, regional, and metro core networks that incorporates Infinera’s own large-scale, indium phosphide-based active photonic integrated circuits (PICs) integrating optoelectronic devices such as lasers, modulators, and photodiodes.

In contrast to the Infinera Line System 1 (ILS1) that provides photonic transport and amplification for either 40 or 80 DWDM wavelengths in the DTN, the next-generation high-capacity, ultra-long-haul Infinera Line System 2 (ILS2), which begins shipping this summer, incorporates technology based on Infinera’s second platform for photonic integration, its new highly integrated all-optical planar lightwave circuits (forming passive PICs).

With the ILS2, Infinera is introducing two passive PICs, designed to deliver benefits similar to the existing active PICs, including greater density of functionality in a smaller space, reduced power consumption, simplified manufacturing, and enhanced reliability. “This [technology] is doing on the passive optical side what we've already achieved on the active PIC side,” says Geoff Bennett, director of product marketing.

The passive PICs are based on a technology platform acquired in early 2007 with PLC start-up Little Optics (based near an existing Infinera engineering team in Annapolis Junction, MD), which developed and patented the high-index silica-like material Hydex. This allows waveguides with a bend radius as tight as 10µm (about a hundredth that in conventional silica-on-silicon PLCs), enabling denser integration of devices in PICs. Also, integration allows the elimination of more than 90% of the fiber couplings and discrete packages found in non-PIC based systems. The PICs are hence about 100 times smaller (less than 1cm² in area) but with much greater functionality.

The PICs integrate passive devices such as multiplexers, interleavers, variable optical attenuators and waveguides, and a precision filter function enables the use of a 25GHz grid (twice the channel-spacing density of ILS1). This enhancement in spectral density allows transmission of up to 160 DWDM channels of light within the C-band on a single fiber, enabling greater capacity.

Of the two new PICs, WaveMux is a precision multi-wavelength multiplexer/demultiplexer (integrating the functionality of more than 40 devices on a single chip) that supports 25GHz channel spacing. WaveLocker is a wavelength-management device with a continuous gain-flattening filter function, integrating the functionality of more than 10 devices on a chip.

With Infinera’s PICs integrating 10 DWDM channels on a pair of chips, the firm’s systems can turn up 10 channels at a time, simplifying the installation and provisioning process, and making 160 channel systems easier to manage, it is claimed.

This can deliver scalability up to 1.6Tb/s of total optical capacity using the 10Gb/s DTN line cards, 6.4Tb/s once Infinera introduces its next-generation line cards operating at 40Gb/s, and 8Tb/s via 80 channels operating at 100Gb/s each (for a new industry standard in optical capacity on a single fiber, the firm claims).

In addition to enhancements to capacity and flexibility, the ILS2 extends optical reach up to 2500km by augmenting Infinera’s existing range of erbium-doped fiber amplifier (EDFA) modules with a new range of co-pumped and counter-pumped, distributed Raman amplification modules. This can enable greater economies in networks with spans that traverse very long distances with no need to drop traffic. Extended reach also enables greater single-span distances (valuable for applications such as festoon networks or to enable hut-skipping).

Raman amplification leverages technology from the acquisition two years ago of assets of Corvis Corp in Columbia, MD (now combined with Little Optics to form an Infinera center of excellence in Annapolis Junction).

“With the ILS2, we sought to take the features and capabilities of Infinera’s first optical line system to new levels, and create a system with some of the best performance metrics in the industry, while still retaining all the rapid service delivery and plug-and-play capabilities of digital optical networks,” says Chris Liou, VP of product management.

In March, analyst firm Heavy Reading estimated that Infinera had a four-year lead over the rest of the industry in photonic integration technology. “The company established itself as the world leader in photonic integration with its initial PIC pair, launched in 2004,” says Sterling Perrin, a senior analyst at Heavy Reading. “In 2008, the company is proving that it continues to lead in PIC innovation - first with its active PIC roadmap announced earlier in the year and now with its new passive PICs.”

“The relative lack of market investment earlier this decade is threatening to jeopardize DWDM systems’ 13-year success in enabling exponential declines in capital expenditure per bit per kilometer of network backbone capacity,” reckons Dana Cooperson, VP network infrastructure at market research firm Ovum. “Infinera is one vendor that has stepped up investment in innovation to put the market back on the road to exponential improvements,” she adds. “The ILS2, together with the 400G PIC announced in February, widens Infinera's addressable market and maps out the company’s strategy for scaling DWDM to the next level of economical backbone capacity.”

“Integration is the only known technology that can improve the capacity of a network while simultaneously delivering benefits in terms of cost per bit, reliability, scalability, speed of operation, density, and power consumption,” says Infinera’s chief marketing and strategy officer Dave Welch. “Our passive PICs, based on a different platform from our active PICs, demonstrate that PIC technology can be applied to multiple materials, and to multiple points in the design of an optical network. We believe that photonic integration is still at a relatively early stage in its life as a key technology for optics.”

*SAVVIS Inc, which provides IT infrastructure services for business applications, has selected the ILS2 line system to upgrade its regional optical network in California.

The ILS2 system has also been selected by the NXTcomm08 organizers (a panel of 15 judges, including service providers, consultants and technical journalists) for an EOS Award for 2008. The prize for Technology Innovation in Optical Networking is in recognition of “significant innovations, including the implementation of 160 DWDM channels in the C-band”, made possible by the use of passive PIC technology. EOS Award winners represent “the best and most promising advancements to the network-enabled voice, video, and data ecosystem,” says NXTcomm executive director Wayne Crawford.

*On 19 June at NXTcomm08, CEO Jagdeep Singh will give a keynote address discussing issues facing the telecom industry, including the challenge of bandwidth growth and the need for innovation.

See related item:

Infinera targets PIC capacity of 4Tb/s within 10 years

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