recently, The IPEC (International Commission on Optronics) has officially released the industry’s first 100 Gbit/s and 400 Gbit/s PAM4 Optical Module Test Specification based on 100 Gbit/s / Lane (the “Test Specification”), The test specification is led by the IPEC Test Group, China Institute of Information and Communication, Guangxun, Huawei, Solth, ZTE, Netflix and many other member units participated in the compilation, It aims to provide a test basis for the evolution of data center networks to 400GE, Help many optical module manufacturers and their customers in the industrial chain to identify potential interoperability and compatibility problems and risks in advance, Accelerate the scale of the commercial process.
In recent years, the data center market continues to maintain rapid growth, and the construction of a large number of new and transformed data centers has stimulated the market demand of optical modules, and the market scale continues to expand. The optical module rate in data centers is evolving from 100G to 400G. Cloud service companies and large data centers (DC) are the first to start the transition to 400G, according to LightCounting in 2019. The 400G is expected to dominate the data center market by 2023.
In the current 400GE optical module, 4 * 106Gbps PAM4 (400G-DR4, FR4, LR4) are mainly used to achieve 400G signal transmission, 8 * 53Gbps PAM4 or 4 * 106Gbps PAM4 electrical signal are used in the optical port side, and the package form of OSFP or QSFP-DD is adopted. In comparison, the QSFP-DD package is smaller in size (similar to the traditional 100G optical module QSFP28 package), and it is more suitable for data center applications.
As the key hardware of the internal optical network interconnection of the data center to be commercialized in the 400GE optical module, the industry needs to jointly build an open platform to comprehensively verify it. To this end, the IPEC International Optoelectronics Committee officially launched the interworking test standard project of the 400G Ethernet optical module in April 2021, It aims to create an open interoperation platform for 400GE to become commercial and mature; To promote the research process of the open platform, In September of the same year, The IPEC, together with several member units in the Shenzhen Light Expo, Jointly demonstrated the 400GE optical module interoperation test Demo based on the self-developed test platform of the IPEC test group; this time, IPEC officially releases test specifications, This is the industry’s first standard specification for 400GE optical module interchange testing, Hope to provide a favorable basis for the industrial chain to improve communication performance and optimization solutions, To accelerate the maturity and large-scale commercial deployment of the 400GE industrial chain.
The 100 Gbit/s and 400 Gbit/s PAM4 Optical Module Test Specification Based on 100 Gbit/s / Lane
The 400GE optical module generally adopts the signal modulation technology of PAM4 (4-level Pulse Amplitude Modulation: 4-level pulse amplitude modulation), that is, four different signal levels are used for signal transmission, and each symbol cycle can represent the logical information of 2 bit (0,1,2,3). Therefore, to achieve the same signal transmission capacity, the symbol rate of the PAM4 signal only needs to reach half of the NRZ signal, but the signal-to-noise ratio is much worse than the NRZ signal, and the two test methods are quite different.
Test specification more comprehensive and detailed specification 400GE PAM4 optical module test points, to ensure good interconnection between equipment and reliable data transmission, especially from the interoperability receiving sensitivity, interoperability FEC capability, interoperability overload optical power test items, focus on the 400GE optical module interconnection and interoperability system test is clearly defined and specification.
With the gradual commercialization of 400GE, the 800GE interface standard has become the next hot research topic in the industry. The IPEC International Committee on Optoelectronics released the baseline 800 G e n at the end of 2021. At the same time, the CIOE China Optical Expo is planned to show the connectivity performance test of the 800GE optical module at the Shenzhen International Convention and Exhibition Center from December 7 to 9 this year.
The IPEC booth of the 24th CIOE Optical Expo (A71, Hall 12, Shenzhen International Convention and Exhibition Center) and the 800G connectivity exhibition area
The 800GE optical module interconnection performance test focuses on 2 x 400G FR4 specifications, industry leading optical module companies such as Optical Fast, Xtron, Hisense Broadband, CIG, Solce Optoelectronics provide corresponding optical module samples, IPEC test group self-developed 800GE test equipment, VIAVI provides 800GE test analyzer, Keysight and EXFO to provide high performance error reader and oscilloscope. IPEC hopes to provide open interoperability platform for industry, to present 400GE, 800GE optical module interconnection performance test, the future is not only for the introduction of data center 800G technology provides basic data, will also through interoperability network test, performance evaluation for 800G technology in the data center optical interconnection application and promotion to lay a solid foundation.