At the Optical Fiber Communication/National Fiber Optic Engineers Conference (OFC/NFOEC 2013) in Anaheim (19-21 March), ClariPhy Communications Inc of Irvine, CA, USA, which develops high-speed mixed-signal digital signal processing (MXSP) systems-on-chip (SoC) for coherent optical networks, and optical solution provider Sumitomo Electric Industries Ltd (SEI), are demonstrating what is claimed to be the first 100Gb/s coherent CFP technology platform.
The firms say that the demonstration highlights breakthroughs in power and size reduction for 100G coherent transmission, with ClariPhy showing what is claimed to be the industry’s first 28nm CMOS analog-to-digital converter (ADC) and digital-to-analog converter (DAC) suitable for 100G and 200G coherent transmission, and Sumitomo Electric showing an indium phosphide (InP)-based integrated coherent optical engine.
The demonstration comprises real-time transmission as well as capture and detection of coherent signals in both QPSK and 16QAM modulation formats. The combined solution also provides a roadmap to next-generation coherent interfaces in CFP2 and smaller form factors.
The firms note that 100G coherent technology is being rapidly adopted by carriers for long-haul dense wavelength-division multiplexing (DWDM) networks because of its advantages in spectral efficiency and reach compared to the previous generation of 10G (non-coherent) systems. However, the high cost, power consumption and size of existing 100G coherent solutions make them unsuitable for use in shorter-reach metro networks and inter-datacenter links, where cheap, pluggable 10G DWDM solutions such as XFP and SFP+ dominate.
As 10G metro networks become overwhelmed by a surge in bandwidth demand, carriers are calling for a 100G metro solution with the benefits of coherent (high fiber capacity, dispersion tolerance and ROADM compatibility), but in a pluggable form factor at a cost and power per bit that is comparable with or better than 10G. Pluggability also allows reuse of line-cards with 100G client CFP interfaces for DWDM transmission and enables operators to scale their metro transport networks to 100G and beyond with ‘pay as you grow’ flexibility. The technology demonstrated by ClariPhy and Sumitomo Electric enables a 100G coherent interface within the 32W budget specified by the CFP multi-source agreement (MSA).
“2013 will be the year that metro 100G solutions are evaluated and selected by leading service providers, and pluggable coherent is near the top of their list according to our service provider surveys,” comments Andrew Schmitt, principal analyst, Optical, at Infonetics Research. “This allows them to extend coherent 100G to vendor platforms without locking themselves into one equipment vendor’s coherent solution,” he adds. “ClariPhy and Sumitomo are clearly well positioned to meet a market need.”
Most power in a 100G coherent transmission system is consumed by the SoC. A key element in reducing SoC power is migrating from the existing generation of 40nm and 65nm solutions to the 28nm CMOS process, but such migration is gated by the availability of 28nm ADC/DAC technology. ClariPhy has claimed an industry first by sampling 28nm silicon containing a complete ADC and DAC, as well as a phase-locked loop (PLL) driven by a standard commercial reference clock source.
The effective number of bits (ENOB), bandwidth and jitter performance of these 28nm analog blocks meet or exceed all requirements for coherent transmission using 100G QPSK, 100G 16QAM and 200G 16QAM modulations.
ClariPhy is integrating these analog blocks into a single coherent SoC with multi-rate (100G, 200G), multi-mode (QPSK, 16QAM) capabilities as well as other best-in-class features. Combining the power-saving features of 28nm CMOS, power efficient design, and a flexible architecture with a high degree of power versus performance tradeoff capability, ClariPhy’s SoC will reduce power dissipation by as much as 65% compared to currently available application-specific integrated circuits (ASICs), it is reckoned.
By combining their respective power-saving, compact technologies, ClariPhy and Sumitomo Electric will enable what they reckon to be the first 100G coherent solution in a CFP form factor in 2013, which is the first step on a roadmap of pluggable 100G coherent modules that will include CFP2 and ultimately CFP4 solutions and will drive down cost, power consumption and size similarly to what tunable XFP and SFP+ modules have done for 10G DWDM interfaces.
ClariPhy and Sumitomo Electric have collaborated closely in the design of their respective components to optimize power and performance for coherent CFP and CFP2 applications, using the DSP capabilities of ClariPhy’s SoC to address the inherent impairments of a pluggable solution such as insertion loss and reflections caused by the CFP2 connector. By optimizing their solution at a system level, the firms aim to offer OEMs a roadmap of robust pluggable coherent modules that can integrate seamlessly into their systems.
“We share the vision of delivering the game-changing benefits of 100G coherent in the pluggable form factors that have been and will continue to be so successful in optical networking such as CFP, CFP2 and CFP4,” says ClariPhy’s co-founder & chief strategy officer Dr Paul Voois. “With its vertically integrated indium phosphide design and manufacturing capability, and its status as a world leader in optical components, Sumitomo Electric is an ideal partner to work with,” he comments.
“ClariPhy’s proven ability to deliver power-saving coherent SoCs — including successfully resolving the challenge of digital-to-analog converters in 28nm CMOS — will enable the world’s first coherent CFP modules,” says Manabu Yoshimura, general manager of Technology and Marketing Strategy Department at Sumitomo Electric Device Innovations (SEDI). “ClariPhy provides us with the advanced technology to create an industry roadmap for pluggable 100G coherent modules that will reduce cost, power consumption and size.”
