Development analysis of 400G optical communication module

By Hotenda


Broadcom recently announced the release of Tomahawk4, the world's first switch chip with 25.6Tbps switching capability, which can support deployment of 64 * 400G / 128 * 200G / 256 * 100G, with twice the performance of similar switch chips on the market, and is the next generation of ultra-large-scale data centers Ideal part for network. The chip uses a 7nm process, which has greatly improved compared to the previous generation 16nm process. It can carry 64 ports of 400 Gbps (400 megabits) or 256 ports of 100 GbE (100 megabits) switching and routing services on a single chip. The SerDes part still uses 50GPAM4 technology, but the number of integrations reaches 512, achieving the highest level of integration in the industry.

Some institutions believe that Broadcom ’s delivery of Tomahawk4 chips is an important milestone in the deployment of Datacom ’s 400G scale. In the subsequent stage of increasing chip production capacity and batch shipment of switch products, the demand for datacom ’s 400G optical modules will also fall on a large scale.

The key to the capacity of Datalink's 400G optical modules is the 25.6T switch chip. Only when the new-generation switch chip is mature can the cloud giant deploy a 400G network and reduce the average cost of the average bandwidth, and the 400G industry chain will enter the scale deployment stage. As the technical difficulty of the 400G optical module is significantly increased, the market share will be further concentrated to the leader.

After the Broadcom 400G switch chip was sampled in 2017, the 400G switch has been progressing smoothly. In 2018, mainstream switch manufacturers such as Cisco, Arista, Junpier and others rush to release 400G switch products. Tonghua manufacturers such as Xinhua III and Ruijie also successively launched 400G switch products in 19 years, and the switch first achieved 400G high-density forwarding.

Generally, it takes 2-3 years from the launch of the switch chip to the beginning of the volume of the optical module, and usually there is a process of rapid volume.

The market for 100G optical modules started with sample shipments of the first 32X100G switch chip (Broadcom Tomahawk) in 2014. In 2016, 100G optical modules began to scale.

By analogy, Broadcom's 32X400 GTomahawk3 chip began to send samples at the end of 2017. It is expected that 400G will usher in large-scale commercial use by 2020, and this process is expected to be more rapid in combination with the acceleration of traffic bursts.

To achieve the interconnection of the internal optical network of the data center, optical modules are essential. 400G optical communication modules have become the best choice to improve system performance and reduce bandwidth costs. The continuous increase in the number of ports and density has made nearly half of the cost of data center optical networks occupied by optical modules.

A 400G optical module is also called a 400G optical transceiver module. It is mainly used for photoelectric conversion. The electrical signal is converted into an optical signal at the transmitting end, and then transmitted through an optical fiber. At the receiving end, the optical signal is converted into an electrical signal. The 400G optical module has a transmission rate of 400G. It was born to adapt to the network market from 100M, 1G, 25G, and 40G to 100G, 400G, and even 1T. The 400G optical module plays a vital role in building a 400G network system effect.

According to Synergy Research data, by the end of 2018, the number of global hyperscale data centers had reached 430, with the United States accounting for 40% of them. According to Cisco forecasts, global data center traffic will grow to 20.5ZB per year in 2021, and 95% of data center traffic will be cloud traffic.

In current 400G optical modules, 8-channel 53Gbps PAM4 (400G-SR8, FR8, LR8) or 4-channel 106Gbps PAM4 (400G-DR4, FR4, LR4) is used to implement 400G signal transmission on the optical port side, and is used on the electrical port side Eight 53Gbps PAM4 electrical signals are packaged in OSFP or QSFP-DD.

According to LightCounting's forecast, the global optical module market size will benefit from the advancement of 5G construction after the decline in 2018, and it is expected that it will maintain a high growth rate in 2019-2021, reaching US $ 59.40, 6.912, and 7.476 billion.

As the world's largest optical communication market, China's optical module market size reached 1.82 billion US dollars in 2018 and is expected to reach 2.69 billion US dollars by 2021. 5G construction has also brought fierce competition in the optical module industry, and it is expected that a round of reshuffle will be ushered in the future.

400G and other high-frequency optical modules have gradually entered the mass production competition stage from simple new product release competitions, and major manufacturers have been snapping up. At present, China's optical module manufacturers occupy more than 20% of the global market share. The major manufacturers are Zhongji Xuchuang, Guangxun Technology, Xinyisheng, and Ona Technology.

Google, Microsoft, and Amazon have started the 400G upgrade process. However, these companies have not unified their technical routes for next-generation product upgrades.

Amazon prefers 400G products with higher transmission speeds, and Facebook builds a new high-density 100G switching structure, which places greater emphasis on network stability. Google will increase from 100G to 200G to 2x200G modules, mainly using 2x200GSR8 and FR8 optical modules.

Microsoft is more concerned about 400GZR can be used for long-distance interconnection of regional data centers, and then deploy 400G in the data center to achieve ultra-high-speed data interworking across regional data centers.

The new products will also test the technological level of Broadcom competitors, including Intel (barefoot), Huawei, MediaTek (Neophos), Nvidia (Mellanox) and so on.

5G and 400G data centers are twin-type synchronous development. It is expected that with the gradual landing of high-broadband applications in the 5G era, the burst of traffic will be on the order of tens of times.

The commercialization of 5G will be another positive driver for the 400 optical module market. According to the correlation between the upgrade of the optical module and the upgrade of the switch chip, according to the analogy of the 100G time period, it is expected that 400G is expected to usher in large-scale commercial use by 2020.

With the overall 5G capacity in 2020, large data centers are an indispensable infrastructure. The large-scale data center leaf-ridge architecture has become the mainstream architecture. The new switching mode can bring lower latency, and the traditional three-tier architecture has withdrawn from the historical stage.

Connections between switches require high-end optical modules to complete, and the number of high-speed optical modules required by the leaf ridge architecture is huge. The simultaneous implementation of 400G Ethernet technology will continue to grow in the next few years, becoming a speed commonly used on switching chips and network platforms.

The accelerated outbreak of traffic makes cloud vendors inevitably need to upgrade existing data centers or build more data centers. This will greatly increase the use and upgrade requirements of optical communication devices, modules and equipment in data centers, and the structural characteristics and high scalability of large data centers make port 400G upgrade a necessary path. The burst of traffic will become the root force driving the development and upgrading of the 400G optical communications industry.

The global optical module market will reach 16 billion US dollars in 2024, and the proportion of the Ethernet optical module market will increase from 45% in 2016 to 64% in 2024. With the commercialization of 5G, fronthaul modules will increase in volume. It is expected that the steady recovery of capital spending by cloud computing vendors will promote the recovery of the entire industrial chain from data centers, network equipment to high-speed optical modules. With the recovery of many companies' orders this year, the market is expected to welcome growth in the coming year.

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