Due to the continuous growth of data center and cloud computing resource demand, the development of large-scale public cloud data center is driven. With the increasing of global data traffic, the data center is developing from 100g to higher speed, wider bandwidth and lower delay. 400G Ethernet becomes the inevitable trend of data center. TodayETU-Link will introduce 400G optical module in detail.

400G optical module type:

At present, the main packaging forms of 400G optical module include CDFP, CFP8, QSFP-DD and OSFP.

CDFP is the first 400G optical module, which has reached version 3.0 since 2014.

CFP8 is an extension of CFP4. The number of channels increases to 8, and the size increases accordingly. With 16 25G parallel signals, the marketing and application of 400G products should be completed quickly.

QSFP-DD is forward compatible with the former QSFP-28, which is currently a popular type with the smallest size and higher density. QSFP-DD is more suitable for use in short distance data centers.

OSFP is a new type of 400G optical module, much smaller than CFP8, but slightly larger than QSFP-DD, with eight high-speed electrical channels. It still supports 32 OSFP ports on each 1U front panel, and 12.8 Tbps can be enabled per 1U. With integrated radiator, the heat dissipation performance can be greatly improved, and modules with up to 15W power can be realized in switch cabinet with traditional air flow.

According to the prediction of global cloud data (GCI), the number of large-scale quantity centers will increase from 259 in 2015 to 485 in 2020, and the share of large-scale data centers in all data center services will increase from 21% in 2015 to 47% in 2020.

Selection of 400G optical module in data center:

① Tor switch to server interconnection scenario no more than 2.5m, can select 400G DAC.

② Tor switch to server interconnection scenario no more than 30m, can select 400G AOC.

③ For the interconnection scenario of Spine-Leaf switch not more than 100m, 400GBASE-SR8 QSFP-DD optical module should be used, and MPO/MTP-16 OM4 multimode optical fiber should be used for wiring.

④For the interconnection scenario of Spine-Leaf switch not more than 150m, 400GBASE-SR4-QSFP-DD optical module should be used, and MPO/MTP-12 OM5 multimode optical fiber should be used for wiring.

⑤For the interconnection scenario of Spine-Leaf switch not more than 500m, 400G DR4 QSFP-DD optical module should be used, and MPO/MTP-12 OS1a single-mode optical fiber should be used for wiring.

⑥ 400G FR8 QSFP-DD optical module with OS2 single-mode optical fiber can be used for data center interconnection scenario of no more than 2km.

⑦ 400G-LR8 OSFP optical module with OS2 single-mode optical fiber can be used for data center interconnection scenario of no more than 10km.

⑧ 400G-ER8 OSFP optical module with OS2 single-mode optical fiber can be used for data center interconnection scenario of no more than 40km.

⑨ 400G-ZR CSFP2 optical module with OS2 single-mode optical fiber can be used for data center interconnection scenario of no more than 120km.

At present, the influence of 100G is growing steadily, and its application in data center is more and more extensive. Compared with 100G, 400G has higher rate, density and economy, which can meet the development needs of data center in the future. But the popularization of 400G still needs time, and 100G is still the focus. ETU-Link will continue to develop higher rate optical modules to meet the market demand for different rate optical modules.