While all the above sound promising, there are still several hurdles that need to be overcome before the industry sees a broad adoption of CPO in data centers. For example, because CPO requires silicon to be near the photonics, the traditional design rules of faceplate pluggable optics no longer apply. Each of the three broader groups of CPO applications today (Ethernet switches, machine learning, and disaggregation) requires different sets of design trade-offs and serviceability concerns. Professionals in the industry are currently debating exactly what those design rules and interface specifications should be.
Cost is another challenging factor. Prices must come down for CPO to compete with the projected cost of USD$0.60/Gb in 2024 for 400G-DR4 optics. Take heart though that significant savings are expected due to CPO's lack of retimers, clock-and-data-recovery (CDR) chips, expensive ultra-low-loss PCB material, and enclosure hardware.
Despite these obstacles, it's clear that CPO is the next major step on the path toward integration of optical and electrical data interfaces. The Co-Packaged Optics Collaboration and the Optical Interconnect Forum (OIF) have taken leadership roles in coordinating input from industry leaders like Synopsys to define CPO specifications and more, including:
- A defined standard for the channel between electrical and optical components
- A standardized interface to enable the electrical and optical components to communicate effectively and reliably
- Design tools to develop and verify integrated electrical and photonic ICs
Synopsys provides OptoCompiler™, an integrated platform for the design, layout, simulation, and verification of electrical and photonic integrated circuits. OptoCompiler enables designers to capture their designs as schematics and choose domain-specific circuit simulators and DesignWare® IP to analyze the performance of their electrical/optical interface channel and CDR. As the above standards evolve and the demand for CPO rises, we continue to update our tools and IP to help customers efficiently migrate toward co-packaged optics and all the innovation that can occur through single package integration of electrical and photonic dies.