1.1.Traditional Pluggable:
Standard modular packages (SFP/SFP+/QSFP/QSFP-DD/OSFP) integrate a DSP (Digital Signal Processor). It can handle signal repair on long PCB traces, but consumes more power.
1.2.LPO
LPO (Linear Pluggable Optical Device) is a new generation of optical interconnect technology that removes the power-consuming digital signal processor (DSP) from traditional optical transceivers and transfers the signal processing function to the host switch ASIC, thereby enabling the optical module to operate as a simple analog interface.
1.3.NPO
NPO (Near-Package Optical Device) is an optical interconnect technology that lies between traditional pluggable modules and fully integrated co-packaged optical devices (CPO). It moves the optical engine from the front panel of the switch to a location adjacent to the switch's ASIC on the same substrate or printed circuit board, thereby shortening the electrical path and significantly reducing power consumption.
1.4.CPO
CPO (Co-packaged Optical Device) represents the highest level of integration in optical interconnect technology, where the optical engine and the switching ASIC are packaged on the same substrate, reducing the electrical distance between them to only a few millimeters. Power consumption is extremely low, but maintainability is extremely poor.
2.Technical Comparison of The Pluggable, LPO, NPO, and CPO
With the development of science and technology and the widespread application of optical communication, optical module packaging and integration technology has continued to evolve, and now four mainstream types have emerged: pluggable, LPO, NPO, and CPO. Their core differences are as follows:
| Technical Feature | Traditional Pluggable | LPO (Linear Drive) | NPO (Near-Packaged) | CPO (Co-Packaged) |
| Signal Processor | Built-in DSP (Digital Signal Processor) | No DSP (Direct Linear Drive) | Integrated/External DSP | DSP-free (Highly Integrated) |
| Location | Front Panel (Standard Port) | Front Panel (Standard Port) | Motherboard (Near ASIC) | Inside Substrate (With ASIC) |
| Distance (Max) | Long Reach (>10km with DSP) | Short Reach (<100m) | Medium Reach (<500m) | Short Reach (<100m) |
| Cooling Difficulty | Low (Edge Airflow) | Lowest (Coldest Module) | Moderate (Internal Airflow) | Extreme (Thermal Hotspot) |
| Maintenance | Hot-swappable (Manual) | Hot-swappable (Manual) | Complex (Requires Disassembly) | Fixed (Non-repairable) |
| Analog Comparison | Like a Loudspeaker (Self-amplified) | Like a Megaphone (Relies on Voice) | Like a Neighbor (Moving Closer) | Like a Microphone in Brain (Fused) |
| Latency | ~100ns (High) | <1ns (Minimal) | ~50ns (Moderate) | <1ns (Minimal) |
| Power per Bit | Highest (100%) | ~50% Reduction | ~25% Reduction | >50% Reduction |
| Application Stage | Mass Production (Mature) | Scaling Up (AI Backends) | Pilot/Trial Phase | R&D / Next-gen Prototype |
3. Speed Applicability & Deployment Status
Due to the explosive demand for AI and computing power, the technologies of the traditional pluggable, LPO, NPO, and CPO are evolving and changing very rapidly. The timeline of each packaging technology is as follows:
| Technology | Target Speeds | Current Market Phase | Timeline for Mass Scale |
| Traditional | 400G / 800G / 1.6T | Mass Production | Current (Dominant) |
| LPO | 800G / 1.6T | Early Mass Production | 2025 - 2026 |
| NPO | 1.6T / 3.2T | Early Pilot/Niche | 2026 - 2027 |
| CPO | 3.2T / 6.4T+ | Early Pilot/Niche | 2027+ |
| Category | Company | 1.6T / Next-Gen Progress | Estimated Mass Production |
| Solution Giants | NVIDIA / Broadcom / Marvell | Designing 1.6T/3.2T DSPs and CPO-ready switch ASICs (e.g., Tomahawk 5/6). | Roadmap 2026-2027 |
| Tier-1 Manufacturers | Innolight (中际旭创) | Lead in 1.6T Pluggable and 800G LPO mass shipping. | Q1 2026 (1.6T) |
| Tier-1 Manufacturers | Coherent (Finisar) | Focus on high-power EML lasers for 1.6T and Silicon Photonics. | Q2 2026 |
| Leading Makers | Eoptolink (新易盛) | Strong 800G/1.6T LPO portfolio for AI clusters. | Now (800G LPO) |
| Emerging Leaders | HG Genuine (华工正源) | 800G LPO mass prod; 1.6T Silicon Photonics sampling. | H2 2026 |
Conclusion: No, these technologies will coexist and jointly promote the widespread use of optical interconnect technology for a long time to come. The reasons are as follows:
LPO is the AI King (Short-term): For 800G/1.6T intra-rack GPU clusters, LPO is winning because it offers CPO-like power savings while remaining hot-swappable.
Pluggables Won't Die: Traditional modules are essential for Long-reach (DCI) and multi-vendor environments where robust DSP signal repair is mandatory.
CPO is the 3.2T Necessity: CPO is not yet a "pluggable killer" at 1.6T due to maintenance risks (if the optics break, you lose the switch). However, at 3.2T, PCB copper loss will force the industry into CPO's arms.
