CFP2
Understanding CFP2
High-Density Optical Transceivers for Core Networks
The CFP2 optical transceiver represents a major evolutionary step in high-speed optical networking. Standardized by the CFP Multi-Source Agreement (MSA), CFP2 was designed to address the physical port-density limitations of the original CFP module. By reducing the width of the transceiver to 41.5 mm, network equipment manufacturers could double the number of optical interfaces on switch linecards, significantly increasing the total data capacity per rack unit.
CFP2 modules support a wide range of optical transmission technologies. For client-side connections, the module uses standard multi-mode or single-mode fiber links to transmit 100 Gbps data over distances ranging from 100 meters to 10 kilometers. For line-side applications, CFP2 coherent transceivers use polarization multiplexing and quadrature amplitude modulation (QAM) to transmit data over long-haul fiber links. The reduced power dissipation of the CFP2 format (typically under 12W) simplifies system cooling design compared to the original CFP.
CFP2 Coherent Architectures: ACO and DCO
CFP2 coherent transceivers are available in two primary architectures: Analog Coherent Optics (ACO) and Digital Coherent Optics (DCO). CFP2-ACO modules house the optical components, including lasers, modulators, and receivers, but lack the digital signal processor (DSP). The analog signals are routed over the electrical connector to a DSP located on the host board. This architecture reduces the power consumption and cost of the pluggable module, making it popular for high-density switches.
CFP2-DCO modules integrate the DSP directly inside the pluggable transceiver. This simplifies the host board design because all digital-to-analog and analog-to-digital conversion, carrier recovery, and forward error correction (FEC) are handled inside the module. CFP2-DCO transceivers can interface with standard host boards using digital protocols like CAUI-4, allowing coherent transmission to be added to existing routers without modifying the host hardware. This plug-and-play capability makes DCO modules the preferred choice for modern open-line networks.
Key Mathematical Relations
Technical Specifications Comparison
| CFP2 Module Class | Primary Optical Target | Integrated DSP | Typical Power Range |
|---|---|---|---|
| CFP2-SR4 | 100G Client (Short Range Multimode, 100m) | No | 4 to 6 Watts |
| CFP2-LR4 | 100G Client (Long Range Singlemode, 10km) | No | 6 to 9 Watts |
| CFP2-ACO | 100G/200G Line (Analog Coherent) | No (Host DSP required) | 8 to 12 Watts |
| CFP2-DCO | 100G/200G/400G Line (Digital Coherent) | Yes (On-module DSP) | 18 to 22 Watts |
Frequently Asked Questions
What is the primary benefit of CFP2 over the original CFP?
CFP2 is half the physical width of the original CFP module. This allows network equipment manufacturers to double the port density on switch and router linecards while reducing the power dissipation per port.
What is the difference between CFP2-ACO and CFP2-DCO?
CFP2-ACO contains the analog optical components and relies on a DSP on the host board. CFP2-DCO integrates the coherent DSP directly inside the pluggable module, enabling digital connection to standard host hardware.
Can CFP2 modules support 400 Gbps transmission?
Yes, modern CFP2-DCO coherent modules utilize advanced DSPs and PM-16QAM modulation to support 400 Gbps transmission over metro and long-haul optical networks.