Recently

owing to the thriving business of internet applications

such as cloud computing and big data

communication traffic is growing rapidly.The fifth generation mobile communication technology will also further accelerate this trend.In order to satisfy the need of high capacity

high terminal density

lower power dissipation of data center interconnectivity and the need of metropolitan area network application

100 Gbit/s optical module has evolved from Centum Form-factor Pluggable（CFP）to CFP2 and further to Quad Small Form-factor Pluggable（QSFP）.The reduction in size and power dissipation of the optical module is a greater challenge to transmitter optical sub-assembly.Therefore

adopting hybrid-integrated packaging technology is the future direction for Transmitter Optical Sub-Assembly（TOSA）packaging

which can not only reduce the size of TOSA

but its power dissipation and cost as well.In this article

we introduce a QSFP28 100 Gbit/s hybrid-integrated Electroabsorption Modulated Laser（EML）TOSA

including its core technology

and show four eye diagrams that are up to the standard of 100 GBASE-LR4.Finally

a brief prediction of the future development of TOSA is made.