Finisar and Oclaro unveiled their first CFP2 optical transceiver products at the recent ECOC exhibition in Amsterdam. JDSU also announced that its ONT-100G test equipment now supports the latest 100Gbps module form factor.
The CFP2 is the follow-on module to the CFP, supporting the IEEE 100 Gigabit Ethernet and ITU OTU4 standards. It is half the size of the CFP (see image) and typically consumes half the power. Equipment makers can increase the front-panel port density from four to eight by migrating to the CFP2.
Oclaro also announced a second-generation CFP supporting the 100GBASE-LR4 10km and OTU4 standards that reduces the power consumption from 24W to 16W. The power saving is achieved by replacing a two-chip silicon-germanium 'gearbox' IC with a single CMOS chip. The gearbox translates between the 10x10Gbps electrical interface and the 4x25Gbps signals interfacing to the optics.
The CFP2, in contrast, doesn’t include the gearbox IC.
"One of the advantages of the CFP2 module is we have a 4x25Gbps electrical interface," says Rafik Ward, vice president of marketing at Finisar. "That means that within the CFP2 module we can operate without the gearbox chip." The result is a compact, lower-power design, which is further improved by the use of optical integration.
"That 2.5x faster [interface of the CFP2] equates to about a 6x greater difficulty in signal integrity issues, microwave techniques etc"
Paul Brooks, JDSU
The transmission part of the CFP module typically comprises four externally modulated lasers (EMLs), each individually cooled. The four transmitter optical sub-assemblies (TOSAs) then interface to a four-channel optical multiplexer.
Finisar's CFP2 design uses a single TOSA holding four distributed feedback (DFB) lasers, a shared thermo-electric cooler and the multiplexer. The result of using DFBs and an integrated TOSA is that Finisar's CFP2 consumes just 8W.
Oclaro uses photonic integration on the receiver side, integrating four receiver optical sub-assemblies (ROSAs) as well as the optical demultiplexer into a single design, resulting in a 12W CFP2.
At ECOC, Oclaro demonstrated interoperability between its latest CFP and the CFP2. “It shows that the new modules will talk to existing ones,” says Robert Blum, director of product marketing for Oclaro's photonic components.
Meanwhile JDSU demonstrated its ONT-100G test set that supports the CFP2 and CFP4 MSAs.
"Initially the [test set] applications are focused on those doing the fundamental building blocks [for the 100G CFP2] – chip vendors, optical module vendors, printed circuit board developers," says Paul Brooks, director for JDSU's high speed transport test portfolio. "We will roll out more applications within the year that cover early deployment and production."
The standards-based client-side interfaces is an attractive market for test and measurement companies. For line-side optical transmission, much of the development work is proprietary such that developing a test set to serve vendors' proprietary solutions is not feasible.
The biggest engineering challenge for the CFP2 is its adoption of high-speed 25Gbps electrical interfaces. "The CFP was based on third generation, mature 10 Gig I/O [input/output]," says Brooks. "To get to cost-effective CFP2 [modules] is a very big jump: that 2.5x faster [interface] equates to about a 6x greater difficulty in signal integrity issues, microwave techniques etc."
The company says that what has been holding up the emergence of the CFP2 module has been the 104-pin connector: "The pluggable connector is the big headache," says Brooks. "The expectation is that very soon we should get some early connectors."
The test equipment also supports developers of the higher-density CFP4 module, and other form factors such as the QSFP2.
JDSU will start shipping its CFP2 test equipment in the first quarter of 2013.
Oclaro's second-generation CFP and the CFP2 transceivers are sampling, with volume production starting in early 2013.
Finisar's CFP2 LR4 product will sample in 2012 and enter volume production in 2013.