Traditional pluggable optical modules have been highly successful because they offer operational flexibility, field serviceability and mature manufacturing flows. As AI fabrics push toward 800G, 1.6T and beyond, however, the electrical interface between switching silicon and optical modules becomes more challenging. Higher lane speeds increase signal-integrity pressure, retimer power and thermal density.
LPO, CPO and NPO are three related approaches that address this pressure from different points in the system architecture. They are not simply faster versions of traditional modules; they are attempts to reduce unnecessary electrical conversion, shorten high-speed paths and improve the power profile of optical connectivity.
This architectural shift is supported by a visible standards timeline. In 2023, OIF published the industry's first 3.2 Tb/s co-packaged module implementation agreement, defining an interoperable CPO module direction for Ethernet switching applications. More recent Ethernet roadmaps place 1.6T interfaces, LPO and energy-efficient design among the technologies enabling the next phase of AI and cloud connectivity.
LPO: lower power through a simpler electrical path
Linear Pluggable Optics removes or reduces retiming inside the optical module and relies on the host system to manage signal integrity. This can lower module power and latency while preserving the familiar pluggable operating model. For AI clusters, the value is especially clear where high-density links must operate within strict power and cooling envelopes.
Phostach's LPO direction targets up to 70% power consumption reduction while maintaining stability through device characterization, EM simulation and qualification support. The key requirement is disciplined link engineering: every connector, trace, optical engine and host interface must be designed as part of one channel.
CPO and NPO: moving optics closer to compute
Co-Packaged Optics and Near-Packaged Optics move the optical engine closer to the switch ASIC, GPU or accelerator. By shortening the electrical channel, these architectures can reduce high-speed loss, lower power spent on electrical equalization and improve bandwidth density around compute. This is especially important as future platforms move toward 3.2T and 6.4T optical engine directions.
Compute-adjacent optics: CPO/NPO architecture direction moves optics closer to compute with DSP and retimer-free linear interface design and SerDes-aligned I/O. The result is a design path aimed at lower power, lower latency and denser optical connectivity for next-generation AI networks.
Why these approaches are better for future AI infrastructure
The advantage of LPO, CPO and NPO is not only component-level efficiency. Their larger value is architectural: fewer conversions, shorter electrical paths, tighter integration and better alignment between optical engines and compute I/O. Compared with traditional retimed pluggables, these approaches can help improve power efficiency, reduce latency and unlock higher front-panel or package-adjacent bandwidth density.
The transition will require careful validation across interoperability, compliance, thermal performance and reliability. Phostach's technology platform is built around that requirement, combining EM simulation expertise, optical engine integration and customer qualification support for high-speed AI infrastructure.