Recently, Wuxi Taclink released the industry's first 400G 40km optical transceiver module based 
on the single channel 100G non-coherent solution—400G ER4 QSFP56-DD optical Transceiver module.

400G long distance transmission optical module mainly has two solutions so far: non-coherent and coherent. The 400G ER4-lite based on the non-coherent solution with insufficient link budget and hard to meet the requirements of metropolitan applications. The 400G optical module based on the coherent solution could meet the long-distance link budget, but the core technology exists with technical barriers. Besides, it was too expensive to use coherent solutions in the metropolitan applications.

Taclink’s 400G ER4 non-coherent optical Transceiver module could meet 40km transmission distance while balancing the cost with significant advantages, its power consumption is much lower compared with current coherent solution in the market. Meanwhile, the core technology of Taclink is independent, which not only gives more feasibility to continuous iterative upgrade in the future, but also brings the strong market competitiveness in DCI and MAN scenarios demand of medium and long distance 400G application. 

Taclink’s 400G QSFP56-DD ER4 optical transceiver module is compliant with QSFP-DD MSA and selected standard QSFP-DD Type2 package. Its electrical interface is compliant with the 400GAUI-8 interface as defined by IEEE 802.3bm which use 8x53G PAM4 coded signal and support standard KP4 FEC RS (544,514). The optical interface uses duplex LC, and support transmitting 4x106G PAM4 encoded signals. There’re four 56Gbaud nLWDM EML lasers used on the transmission side, and four 56Gbaud receivers integrated with SOA, which guaranteed the fiber link budget requirements on the receiver side.

As for OSA advanced package and processing technologies, Taclink optimized the designs cover key factors contains coupling efficiency, output power, signal integrity and other indicators together. By improving the integration of component, the power consumption reduced, at the meantime, it also greatly enhanced the transmission performance to ensure 40km long distance transmission of 400GE network. 

Currently, Taclink’s 400G QSFP-DD ER4 has finished module level test at customer's 5G optical device lab. Test result showed error free after continuous operating over 72 hours with 40km fiber when KP4 FEC is enabled and meet the requirement of symbol error less than 8. Beyond that, module’s maximum power consumption is less than 12W under full temperature operation. Furthermore, module’s OMA power of each lane is over 4dBm, and the receiving sensitivity each lane is less than -16 dBm. The total link budget is much better than the 40km transmission requirement, Tackink’s 400G QSFP-DD ER4 could even realize 50km transmission of G.652 optical fiber at room temperature.