By Fred Greenberg, Director of Engineering

Co-Packaged Optics (CPO) and Linear Pluggable Optics (LPO) address different layers of AI optical interconnects. While CPO maximizes bandwidth density, LPO balances power, cost, and deployability. 

What Is Co-Packaged Optics (CPO)?

CPO places optical engines in close physical proximity to the switch ASIC, typically within the same package or PCB substrate. 

• The Mechanism: Shortening the electrical interconnect between the switch SerDes and the optical interface dramatically reduces signal loss. This eliminates the need for power-hungry signal conditioning.
• The Challenge: Tight coupling between the optics and the switch ASIC complicates manufacturing, testing, and thermal management. 

What Is Linear Pluggable Optics (LPO)?

LPO takes an evolutionary approach. Instead of redesigning the system architecture, it simplifies the optical module itself by removing the Digital Signal Processor (DSP). 

• The Mechanism: The design uses linear driver and transimpedance amplifier (TIA) components, shifting signal compensation entirely to the host switch ASIC. 
• The Benefit: Eliminating the DSP significantly reduces module power consumption and Bill of Materials (BOM) costs, especially in short-reach applications. 
• The Form Factor: LPO retains standard pluggable form factors like QSFP-DD. This allows integrators to deploy modules in existing switch platforms while preserving hot-swap ability, established operational workflows, and vendor interoperability. 

At OSS, we are dedicated to breaking performance barriers. We are actively exploring and integrating breakthrough technologies like LPO to help our customers build cooler, faster, and more cost-effective AI environments.