Acacia Communications unveils Jannu coherent DSP, 1.2-Tbps optical module plans

Sept. 23, 2021
The device will support 1.2-Tbps optical modules – which Acacia plans to offer as the Coherent Interconnect Module 8 (CIM 8) in a form factor slightly larger than a CFP2.

Acacia Communications, now part of Cisco, has introduced is latest coherent DSP, the Jannu. The device will support 1.2-Tbps optical modules – which Acacia plans to offer as the Coherent Interconnect Module 8 (CIM 8) in a form factor slightly larger than a CFP2.

Tom Williams, vice president of marketing at Acacia, describes Jannu as an eight-generation coherent DSP that leverages second-generation 3D Shaping (Acacia's answer to probabilistic constellation shaping) built on 5-nm CMOS. The device will deliver less than half the power/bit of current 800G technology based on 96-GBaud approaches, he says.

The resulting module will feature continuous baud rate adjustment up to 140 GBaud to enable optimal transmission rate/distance tradeoffs applications ranging from long-haul transport to data center interconnecte. Williams said that, in addition to meeting 1.2-Tbps requirements, the module will support extended reach 800G to enable such transmission rates in 90% of reach use cases. This figure compares to a less than 20% coverage offered by current 800G technology, Williams asserts. The modules, which Acacia describes as “Class 3” (with Class 2 comprising “multi-haul embedded modules and 400G faceplate pluggables where the latter was driven by standardization efforts that drove heavy investments into products centered around 16QAM, 60+Gbaud per 75-GHz channel transmission,” in the words of an Acacia blog) will leverage 4 bits/symbol modulation transmitting across 150-GHz channels in single-carrier format.

Despite the savings in power/bit, the size of the pluggable CIM 8 will be larger than a CFP2 because the power requirements will be beyond what the latter package can accommodate. Williams declined to reveal what those power requirements will be.

Acacia has provided early prototype hardware to its lead customers, whom Williams did not identify. He said that there was more than one; parent Cisco would seem a likely member of this list. Williams said that users of transceivers based on Acacia’s Pico DSP (such as the AC1200) would form a logical target market for the CIM 8 once it reaches general availability, which Williams estimated will occur in early 2023. He added that Acacia will offer Jannu as a standalone product to "select customers."

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