Challenges and Opportunities of 400G Optical Modules

At this stage, the global network traffic continues to rise, and users need more bandwidth to meet application needs, which promotes the extensive application of 400G Ethernet in large data centers. The 400G optical module, as the key hardware equipment of the optical network interconnection in the data center, also has a good development prospect. More and more network communication equipment manufacturers, cloud service providers and optical component suppliers have joined the 400G army.

In order to keep up with the trend of the times, ETU-LINK has also begun to enter the research and development stage of 400G products. In the next few years, there will be a large number of 400G products on the market to meet different network needs, such as 400G QSFP-DD optical modules, 400G QSFP-DD DAC high-speed cables, 400G QSFP-DD AOC active optical cables, etc.

The promulgation of the 200G/400G Ethernet standard has brought new optical module packages to the industry, such as QSFP-DD, OSFP and CFP8 defined by IEEE and MSA groups. The optical interfaces of these packages use 16 * 25Gb/s NRZ or 8 * 53Gb/s PAM4.

Although PAM4 modulation technology can greatly improve the throughput, it also brings some problems to 400G, such as more complex physical structure and easy error in signal transmission.

Therefore, the complex 400G test project has brought many new challenges to optical module suppliers. In order to ensure that the optical modules received by users are of good quality, optical module manufacturers must use more professional optical module detection equipment, and must have a higher detection level and R&D technology. At the same time, they can ensure that the 400G optical module is connected and upgraded with the existing network infrastructure. In addition to the factors affecting the testing technology, the R&D/manufacturing/testing costs of 400G optical modules are also problems that manufacturers need to solve.

Although the 400G Ethernet standard has been approved for a long time, the entire industry (including OEM manufacturers, network operators, etc.) is still solving basic connection problems, such as trying to solve the problems of optical module frame transmission error, data packet loss, etc., to ensure the accuracy and reliability of optical module transmission. For optical module manufacturers, product quality inspection is an important link to establish customer trust.

The main test items of 400G optical module include: extinction ratio and optical modulation amplitude test, forwarding performance test, eye diagram test, jitter test, bit error rate test, etc. However, although the complex 400G optical module testing technology still needs to be improved, with the promotion of 5G, artificial intelligence, virtual reality (VR), cloud computing and other applications, 400G Ethernet will flourish.

At present, some manufacturers have begun to provide 400G solutions to the market, such as Cisco, Arista, etc. In the face of this situation, some small-scale optical module suppliers consider 400G optical module testing as an important factor for their selection, because the quality and delivery speed of 400G products determine their profitability.