Co-packaged optics: putting the pieces together

An article written by John Williamson for Optical Connection Magazine, in collaboration with Martin Vallo, PhD., Senior Analyst Photonics for Yole Intelligence, part of Yole Group – Now starting to achieve real-world deployment viability, Co-Packaged Optics (CPO) technology is considered by many optical movers and shakers to have a rosy commercial future. As an illustration, in a recent report that focuses on the demand for the technology within data centres, the analyst firm CIR Inc reckons that by 2027 the CPO market will reach US$5.4 billion in revenues, writes John Williamson.

Serializer/Deserializer (SerDes) links are a hot topic in CPO conversations. In the Co-Packaged Optics 2022 – Focus Data Centers report, Martin Vallo, Ph.D., senior analyst Photonics, within the Photonics and Sensing Division at Yole Intelligence, believes that standardised electrical SerDes links for 224Gbps data rates are among the musthaves to make CPO mainstream. He says these are needed to provide signalling over a multitude of link types, including Die to Die (D2D), Chip to Chip (C2C), Chip to Module (C2M), Medium-Reach Chip to Chip (MR), and Long-Reach Chip to Chip (LR).

Meantime, Jock Bovington, Cisco and OIF Member, stresses that one of the benefits of co-packaging is to reduce the overall power consumption. In this context he refers to the fact that systems built with pluggable modules contain reasonably powerful SerDes in the ASIC, as well as the pluggable module. “When co-packaged – either on the same substrate (CPO) or on a High Density Interposer (HDI) substrate (Near Packaged Optics, NPO) – the channel will have significantly less loss,” remarks Bovington. “Which enables the use of a significantly lower power SerDes such as XSR (10dB) or XSR+ (13dB). The OIF developed both types of electrical interfaces.”