SAN FRANCISCO -- OFC 2014 -- ClariPhy has rocked into OFC with a brace of new products that, it believes, meets the form factor and price points that system vendors and network operators are demanding for metro network applications.

Coherent technology is already in widespread use in 100G, long-haul DWDM (dense wavelength division multiplexing) networks, given its spectral efficiency and reach advantages.

For short-reach metro networks, however, these coherent advantages have been completely out of reach because of their high price tag, high power consumption and size. Instead, inexpensive pluggable 10G DWDM solutions, such as XFP and SFP+, are typically used.

However, capacity pressures in metro networks means carriers are now in need of transport systems that offer the dispersion tolerance and ROADM compatibility found in a coherent solution, but at a power-per-bit and cost that matches, or is better than, current 10G modules.

Oh yeah, and it has to be in a pluggable form factor too. Pluggable advantages include the reuse of line cards with 100G client CFP interfaces for DWDM transmission, and the ability to scale metro transport networks to 100G based on pay-as-you-grow flexibility, compared with the spend-it-all-now-and-grow-into-it mentality that typically delays investment.

Two back-to-back announcements from ClariPhy Communications Inc. aim to deliver the benefits of coherent solutions to metro applications and SDN, with both products currently sampling ahead of commercial availability later this year.

The first is the LightSpeed-II CL20010 SoCs, which can be used for 200G and 400G DWDM transport scenarios. The SoC supports single-carrier 200G transmission using 16QAM modulation, providing dual-carrier 400G super channels on 75GHz DWDM spacing. According to ClariPhy, the SoC can increase fiber capacity 170% over today's 100G coherent systems and drops cost by approximately 50%.

The CL20010 acts as a single chip OTN muxponder that multiplexes two independent 100G client signals (OTU4 or 100G Ethernet) onto a single DWDM wavelength over the same optics now used for 100G coherent transmission. Carriers have the flexibility to use a single, software-programmable line card for 200G and 400G transmission at reaches of more than 600km, and 100G transmission exceeding 3,500km.

ClariPhy also announced another LightSpeed-II family member, the CL10010-Z SoC. The claim to fame for this SoC is integration. It features: a high-speed analog-to-digital and digital-to-analog converter; a coherent DSP that supports 40G QPSK, 100G QPSK and 100G 16QAM; multiple low-power forward error correction (FEC) options; and an integrated OTN framer/mapper for 100G Ethernet connectivity. It enables a 100G coherent CFP module to operate within the 32W power budget defined by the CFP MSA (multisource agreement), and delivers extended performance to 1,200km connections.

When asked about the importance of pluggability, especially as it pertains to the metro, Dr. Paul Voois, co-founder and chief strategy officer at ClariPhy, explained: "There is no swappable coherent low-power solution. This is the first time for a coherent SoC to support 100G coherent CFP. The significance is that it provides a giant leap in power efficiency, as CFP will be 32 watts vs. 80 watts at approximately one fourth of today's cost per bit."

He added: "With CFP, certain size line cards will run out of space. While CFP features DSP inside, CFP2 puts the DSP on the line card where it's easier to control and manage thermals and to run 200G pluggable to enable 200G metro."

ClariPhy is working with pluggable optical module suppliers and with the Optical Internetworking Forum (OIF) to ensure compatibility and performance with coherent CFP2 implementation agreement currently under development in the Forum.

According to Karl Gass, the OIF's Physical and Link Layer Working Group vice chair, "Current power consumption for stuff that goes into a CFP2 module for coherent optics applications [100G Metro or Long Haul] is around 40 watts. Maximum power consumption for the CFP2 MSA is 18 watts, but typical vendors only allow 12 watts. We take the CFP2 transceiver MSA, remove a couple of functions," such as high-power consumption chips, "and use it as a pluggable optics module."

A CFP2-ACO project was initiated approximately a year ago, when OIF members decided they liked the form factor and power budget of the CFP2 pluggable module for a coherent optics transceiver, but the component technology wasn't ready. In the meantime they wanted to move the ADC/DAC/DSP/FEC functions from the module to the host board, and in the process use the module for a pluggable optics solution. The result of the immediate solution was to increase faceplate density and create a coherent optics component in a CFP2 form factor.

Ultimately, the next step rests on the shoulders of carriers that are looking beyond field trials for 200G-400G deployments. What's really next is the fine-tuning of DSP and optics, and the configuration of networks to take advantage of these technologies, all of which will take a couple of years. However, the cost benefits are so compelling that operators should be quite motivated to start feeding their demands into the vendorsphere right now.

— Carolyn Mathas, contributing editor, special to Light Reading