Next-generation PON awaits deployment

The IEEE has already released the first 10G EPON standards, and 10G GPON specs should arrive this year. But it will take more than standards to get carriers to adopt these next-generation PON technologies.

By Stephen Hardy


Overview

The IEEE has already released the first 10G EPON standards, and 10G GPON specs should arrive this year. But it will take more than standards to get carriers to adopt these technologies.


As expected, ratification of the relevant standards has provided the gating factor for the timing of 10-Gbps PON system development. The IEEE reached its initial ratification milestone first, completing IEEE Std. 802.3av-2009, “Physical Layer Specifications and Management Parameters for 10 Gb/s Passive Optical Networks,” last September—and commercially available systems compliant to the standard quickly followed.

The Full Service Access Network Initiative (FSAN) and ITU-T are expected to catch up this fall when they release their XG-PON specifications. Again, carriers can expect their suppliers will have commercially available 10G GPON systems soon after this milestone.

Yet, just because technology is available doesn’t mean it will be adopted quickly, sources say.

10GEPON first to market—again

Once they’re completed, the IEEE and FSAN/ITU-T specifications will prove remarkably similar. In addition to the same nominal data rates, the respective standards will offer specifications for symmetrical and asymmetrical operation, as well as backwards compatibility with their current incarnations to deliver on the promise of seamless upgrade. The wavelengths used will likely be similar, as well.

That said, some differences will prove apparent. The upstream rate for 10GEPON’s asymmetrical version is 1 Gbps; FSAN and ITU-T plan for 2.5 Gbps. The IEEE worked to stretch its standard reach to match GPON’s 20 km; however, the GPON camp is already discussing reaches greater than 20 km, plus splits as high as 1:64 (twice the ratio in IEEE 802.3av) and beyond using C+ optics. XG-PONs are expected to be more “telco grade” than their IEEE equivalents, as well.

Therefore, the 10G EPON segment hopes to leverage its first-to-market advantage as well as it did at 1 Gbps—not to mention the beneficial effects on price of higher volumes. Alloptic (www.alloptic.com), ZyXEL (www.zyxel.com), and ZTE (www.zte.com) have announced either commercial availability of 10G EPON or trials. Carriers might expect Huawei (www.huawei.com) and Fiberhome (www.fiberhomegroup.com) in China and Japanese suppliers, such as Hitachi (www.hitachi.com), Mitsubishi Electric (global.mitsubishielectric.com/bu/communication/index.html), NEC (www.nec.co.jp), and Sumitomo Electric Industries (global-sei.com/products/info/index.html), to make 10G EPON announcements in the future, as well. In North America, Enablence Technologies (www.enablence.com) supports both GPON and EPON in its TRIDENT7 platform, so undoubtedly is pondering its upgrade options, as well.

Meanwhile, a foundation of component and subsystem vendors has sprung up to support the systems suppliers’ efforts. The usual MAC chip-level suspects—PMC-Sierra (www.pmc-sierra.com), Teknovus (which Broadcom recently purchased), and Cortina Systems (www.cortina-systems.com)—now have new competition in Opulan Technologies Corp. (www.opulan.com), which announced symmetrical devices for 10G EPON at the end of last year. The chips include the OPL-06761 for the optical line terminal (OLT) and the optical network unit (ONU) OPL-06760.

In an attempt to tie electronics and optical module vendors together, Vitesse Semiconductor (www.vitesse.com) has created an FTTX Technology Ecosystem. The ecosystem also shows off the capabilities of Vitesse’s laser drivers, transimpedence amplifiers (TIAs), transceivers, and post-amplifiers for 10G EPON (and GPON, as well).

Other silicon suppliers for 10G EPON include Kawasaki Microelectronics America (K-micro; www.k-micro.us), which offers the CTXL1 10G EPON SerDes chip. Phyworks (www.phyworks.com) markets a reference design that features the PHY1090 10-Gbps TIA with the PHY1060 10-Gbps integrated post amplifier, equalizer, and retimer. The transmit path uses the PHY2078 1.25-Gbps burst-mode laser driver. Gennum Corp. (www.gennum.com) offers the single-chip GN7350 10G EPON transceiver for ONU applications that combines clock and data recovery and laser driver functionality. And Xelerated (www.xelerated.com) has positioned its AX family of Ethernet switches at both 10G EPON and GPON.

On the 10G EPON module side, both Hisense (www.hisense.com) and Source Photonics (www.sourcephotonics.com) have joined the ecosystem. Hisense offers the LTX7218 at the OLT and the LTX7219 at the ONU. Source Photonics launched OLT and ONU devices last September. OneChip Photonics (www.onechipphotonics.com) says it has 10G EPON in mind, as well (see “PIC-based transceivers enable cost-effective 1G to 10G PON migration” on page 11).

Jeff Heynen, directing analyst, broadband and video, at Infonetics Research (www.infonetics.com) told attendees at Lightwave’s “Future of Optical Networking 2010” e-conference in January that 10G EPON deployment should begin this year in China and Japan, featuring mainly symmetrical systems. Most trials and deployments of asymmetrical systems will wait until next year, he predicted. A survey of carriers indicated that they see the symmetrical approach as ideal for businesses and power users.

10G GPON plays catch up

While the FSAN and the ITU-T don’t expect to ratify the XG-PON standards until later this year, companies have already begun to jockey for carriers’ attention with pre-commercial prototypes. Huawei jumped into the lead with the first announced trial of 10G GPON technology with Verizon last December. However, sources at both Alcatel-Lucent (www.alcatel-lucent.com) and Motorola (www.motorola.com) tell Lightwave that they also have trials planned for the first part of this year.

For example, Floyd Waggoner, Motorola’s director of global marketing and communications for access networks, said at the end of last year that his company has a trial scheduled with “a customer that we’ve worked with for a very long time and it’s one of the largest operators”—which probably means Verizon. The trial is slated for the first quarter of this year. Meanwhile, Stefaan Vanhastel, product marketing manager for FTTX within Alcatel-Lucent’s Wireline Networks Division, revealed that his company has “a number of trials” scheduled for this year.

Both Vanhastel and Waggoner said the trials indicate a desire for upgrade proof-of-concept rather than near-term deployment. Neither expects to see large-scale rollouts for several years. When deployments do occur, Vanhastel sees demand for both symmetrical and asymmetrical systems. The former will work particularly well for 4G/LTE wireless backhaul and business services delivery, he said, while the asymmetrical will prove useful in applications where carriers want to increase the number of subscribers per PON or provide service to a multiple-dwelling unit.

Central office consolidation may prove another catalyst for 10G GPON deployment. Sayeed Rashid, senior manager, marketing, for broadband access products at Huawei Technologies USA, described this application during the “Future of Optical Networking 2010” e-conference. Because of the extended reach and greater capacity 10G GPON will provide, carriers could use centralized 10G GPON OLTs as aggregation points for multiple existing GPONs, as well as to serve new customers in the coverage areas of those GPONs when they reach exhaustion, he said.

Heynen concurs that significant 10G GPON deployments are not just around the corner. His research indicates that carriers won’t begin to roll out such systems in volume until 2016, he told those at the e-conference. Interoperability concerns will prove one reason for the delay, he said.

The lag in demand will give current GPON suppliers plenty of time to perfect their offerings. In addition to Alcatel-Lucent, Huawei, and Motorola, certainly one would expect Ericsson (www.ericsson.com) to step up to 10G to stay on Verizon’s supplier list. Many of the same vendors listed in the EPON space above—including Hitachi, ZTE, NEC, and Enablence, in particular—will likely follow suit.

The component community hasn’t trumpeted its 10G GPON work as loudly as its EPON activities, but one can expect the system companies have received support from such chip vendors as: Broadlight (www.broadlight.com), PMC-Sierra, Cortina Systems, and Vitesse. Freescale Semiconductor (www.freescale.com) supplied GPON devices to Alcatel-Lucent and, undoubtedly, has its eyes on 10G GPON, as well. Meanwhile, FPGA vendors, such as Altera (www.altera.com) and Xilinx (www.xilinx.com), will likely find their wares in demand until the ASSP community catches up.

Stephen Hardyis editorial director and associate publisher of Lightwave.

Links to more information

Lightwave e-conference: The Future of Optical Networking 2010
Lightwave Online: Verizon Tests XG PON 10G GPON with Huawei Equipment
Lightwave Online: IEEE Task Force Ratifies 10G EPON Standard

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