With the rapid development of 5G services, from the access network to the core, each layer of the bearer network must be upgraded to a higher data rate to meet the needs of the business. However, high speed also means higher power consumption.
In addition, in order to increase the speed of the optical module from 10Gbps to 100Gbps to 400Gbps or even 600/800Gbps, the switching and processing technology (DSP switching core) has been upgraded from 28nm to 16nm, 7nm and the upcoming 5nm CMOS technology to maintain overall power consumption And thermal budget balance.
We know that coherent transceivers rely on DSP to process optical signals. When the DSP technology was first used, its power consumption and heat density were so high that the optical device and DSP had to be physically separated to prevent the optical device and DSP from overheating. In other words, there is analog communication between the module and the system.
In fact, the maximum data rate of the module's analog electrical connector is still limited to 25Gbps. To achieve a higher rate of transmission, you need a very large form factor or line card to accommodate the heat generated by the DSP. With the development of DSP and optical integration, it is possible to co-package digital signal interface (DSP) and optical devices, and digital communication is adopted between modules and systems. Thereby forming an array of coherent optical modules-DCO
Now, by combining new DSP and integrated optical components, 400G rate modules can be realized within the small OSFP and QSFP-DD size specifications. Moreover, since the 50Gbps digital electrical interface using PAM4 is very mature on the host-side side, the DCO module is easy to embed, thereby avoiding the limitations of the bandwidth and repeatability of the ACO module
