Relationship between optical modules and CPO

CPO represents a shift from traditional pluggable optical modules by integrating optical engines directly adjacent to the switch ASIC, improving power efficiency and bandwidth density while changing maintenance and system design requirements.

Traditional Optical Modules

Traditional pluggable optical modules, such as SFP, QSFP, or XPO, are designed to be modular and easily replaceable from the front panel of network switches. They rely heavily on Digital Signal Processors (DSPs) and Clock Data Recovery (CDR) circuits to manage signal integrity, which increases power consumption and latency. These modules are suitable for incremental upgrades and flexible deployments but face limitations in power efficiency, front-panel density, and electrical reach as data rates scale toward 800G and beyond.

Co-

Packaged Optics (CPO)CPO changes the architecture by placing optical engines directly next to the main switch ASIC rather than on the front panel. This shortens the electrical path between the ASIC and the optics, reducing the need for high-power DSPs or retimers, which lowers power consumption and improves energy efficiency.

CP

O enables higher bandwidth density and better signal integrity, making it particularly attractive for AI data centers and high-speed networking where latency and power are critical. However, CPO introduces new challenges: Maintenance: Components are soldered or bonded, so failed parts often require replacing the entire switch or core board rather than a single module. Manufacturing and cooling: Integrating optics so close to the ASIC demands redesigned switch boards and enhanced thermal management.

Operational complexity: Deployment requires careful planning, as CPO is less modular than traditional pluggable optics. Relationship and TransitionCPO and traditional optical modules coexist as complementary strategies: Linear Pluggable Optics (LPO) provides a DSP-less, pluggable solution that reduces power and latency while retaining modularity, serving as a transitional technology toward CPO.

Near-

Packaged Optics (NPO) positions optical engines close to the ASIC but not fully co-packaged, balancing power efficiency with easier deployment compared to CPO. Enterprises can adopt pluggable modules for short-term flexibility while planning for CPO in long-term, high-density deployments. In essence, CPO represents the evolution of optical modules toward deeper integration, higher efficiency, and lower latency, while traditional pluggable modules remain relevant for modularity and ease of maintenance.

The choice between them depends on data center scale, power constraints, and operational priorities.