OIF tackles CFP8-ACO optical transceiver, finishes Multi-Link Gearbox 3.0

Members of the Optical Internetworking Forum (OIF) have decided to develop a successor to the CFP2 Analog Coherent Optics (CFP2-ACO) Implementation Agreement. The new CFP8-ACO optical transceiver will support four wavelengths or carriers, making it appropriate for 400-Gbps and perhaps higher data rate applications using coherent transmission. The group also finished work on Multi-Link Gearbox (MLG) 3.0 agreement.

A wide variety of optical module vendors have adopted the CFP2-ACO as an attractive form factor to support both 100 and 200 Gbps optical transmission rates in the same device (see, for example, "Oclaro shows off coherent CFP2 at 200 Gbps"). The pluggable module's most salient design feature is what it lacks – the digital signal processor (DSP) necessary to enact coherent transmission. That chip is placed on the board instead, resulting in an optical transceiver that is smaller, lower cost, and compatible with DSPs systems houses have developed internally or purchased from such merchant suppliers as ClariPhy Communications and NEL. Depending upon the capabilities of the DSP, the CFP2-ACO will support communications at 100-Gbps via DP-QPSK modulation as well as 200 Gbps via 16QAM.

The CFP8-ACO will take the CFP8 form factor specifications the CFP MSA has created and determine a way to support up to four wavelengths or carriers. The resulting optical module would require no more than 20 W. The 9.5 mm H x 40 mm W format would allow double-stack or belly-to-belly line card configurations of 2x8 in a 16-port line card.

"The OIF is looking ahead to what is needed in 2018, and we need to get started now to support the market needs for more wavelength/carriers in coherent optics modules," said Qorvo's Karl Gass, the OIF Physical and Link Layer Working Group optical vice chair. "Our goal with the CFP8-ACO module is a 4X increase in faceplate density, and we expect to complete this next year."

Meanwhile, the newly completed MLG 3.0 specifications support 100G links and enables independent 10GBASE-R signals to transit physical 20G and 40G lanes. The Implementation Agreement supports three configurations:

1. a 4x25G lane configuration, comprising 20 MLG lanes
2. an 8x25G lane configuration, comprising 40 MLG lanes
3. a 2x20G/1x40G lane configuration, comprising 4 MLG lanes (similar to 40GBASE-R) to carry up to four 10GBASE-R signals.
   

The MLG 3.0 agreement is available on the OIF's website.

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