EUGENE PARK 800G MSA PLUGGABLES
THE ROAD TO 800G MSA PLUGGABLES: CHALLENGES AND REQUIREMENTS
Eugene Park , Senior Technology Marketing Manager at Acacia, looks at the work currently being done in the industry around this new generation of pluggable modules and highlights some of the key features that need to be available before network operators can start
taking advantage of them in their networks. T he adoption and popularity of 400G coherent pluggable modules has been unprecedented, with analysts such as Cignal AI reporting they were the working to set 800G standards, module vendors in parallel are introducing the required technologies to enable low power 120+Gbaud solutions that would fit into small form-factor modules such as QSFP-DD and OSFP. KEY REQUIREMENTS FOR 800G PLUGGABLES
Class 3 ~120 Gbaud rates, as shown in Figure 1b. Channel spacing requirements double to 150GHz for 800G, providing a straightforward network scaling supporting similar reaches to 400G Class 2 devices. As with 400G, this convergence is expected to drive economies of scale of the technology supporting this baud rate class. To realise the modulation capability for Class 3 120+Gbaud operation, advancements in both high-speed optical modulation and supporting components as well as high-speed 112G-per- electrical-lane capabilities were needed to enable 800G MSA pluggables in compact form factors. These optical and electrical high-speed capabilities have already been proven with the introduction of Class 3 performance optimised coherent solutions, such as Acacia’s CIM 8 module which utilises silicon photonics for 120+Gbaud transmission. In addition, a high-level of integration is required to fit this high baud rate technology into QSFP- DD and OSFP pluggable form-factors, all while maintaining high signal integrity and low power consumption. Acacia’s 3D Siliconisation, used in Class 2 400G pluggable modules, is also leveraged for Class 3 800G MSA pluggable modules.
fastest growing coherent generation of all time (Figure 1a). Led by the Optical Internetworking Forum’s (OIF’s) 400ZR implementation agreement, hyperscalers drove volume deployments to support data centre interconnect (DCI) upgrades to take advantage of switch/router ASICs with 400G I/O port speeds. The next-generation switch/router ASICs are being introduced with 800G I/O port speeds, creating the need for 800G optical interfaces for DCI. The 800G pluggable coherent interfaces developed to support these applications will have a lot in common with 400G devices, but there are also some key differences to be considered. Similar to the 400G MSA pluggable cycle, multiple standardisation bodies, including the OIF, Open ROADM, and the IEEE, are working in parallel to provide industry standards for 800G optical transmission and 800 Gigabit Ethernet (GbE), helping to foster economies of scale. And while these organisations are
In coherent transmission, the two primary adjustments for optimising capacity and reach are the transceiver’s baud rate and the bits per symbol modulation order. With 400G MSA pluggable coherent transceivers, the industry converged onto a specific baud rate range and modulation order. The OIF 400ZR outlines the use of 4 bits per symbol 16QAM modulation and a Class 2 ~60Gbaud rate to enable 400G transmission within a 75GHz optical spectrum (Figure 1b). Open ROADM requirements, targeting service providers, also includes 4 bits per symbol 16QAM modulation in the Class 2 ~60Gbaud range, as well as additional transmission flexibility specifying more modulation modes, such as 2 bits per symbol QPSK to enable longer reaches at 200G. At 800G, the industry has converged to a 2x scaling of baud rate resulting in
Figure 1. (a) Plot showing rapid adoption of 400ZRx coherent pluggable modules compared to previous 30Gbaud generation of coherent solutions; (b) 2x scaling of baud rates and channel spacing for ~60+Gbaud Class 2 to ~120+Gbaud Class 3 transition.
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| ISSUE 34 | Q3 2023
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