What is The Difference between Copper SFP and Fiber SFP?

1. What is an SFP module?

SFP stands for Small Pluggable Module. SFP modules are also called SFP fiber optic modules or SFP transceivers. As the name suggests, an SFP module is a small, hot-pluggable fiber optic network device used for data communication.

2. What are the types of SFP modules?

SFP modules come in several types depending on the classification criteria.

2.1 Different Transmission Media

Based on the transmission medium—fiber optic or copper cable—SFP modules are divided into fiber optic SFPs and copper cable SFPs.

Fiber optic SFP modules include: 1000BASE-SX SFP modules, 1000BASE-LX SFP modules, 1000BASE-EX SFP modules, 1000BASE-EZX SFP modules, bidirectional SFP modules, CWDM SFP modules, and DWDM SFP modules. They use LC connectors. Bidirectional SFPs use simplex LC connectors, while other modules use full-duplex LC connectors. When using LC-LC single-mode fiber optic connections, the maximum transmission distance of fiber optic SFP modules can reach hundreds of kilometers.

Copper SFP modules include 1000BASE-T SFP modules. These use RJ-45 connectors instead of LC connectors. 1000BASE-T copper SFP modules can achieve link lengths of up to 100 meters on Cat5e or higher (Cat6/Cat6a) copper twisted-pair cables.

2.2 Differences in Cable Core Diameter

Based on the diameter of the connecting cable's fiber core, SFP modules can be divided into multimode SFPs and single-mode SFPs.

Multimode SFP Modules: These are SFP modules used with multimode fiber optic cables. Multimode fiber optic cables have a larger core diameter than single-mode fiber optic cables, thus supporting multiple propagation modes, but are limited by modal dispersion. Modal dispersion affects the transmission capacity of fiber optic cables; therefore, multimode fiber optic cables are only suitable for relatively short-distance communication, and the same applies to multimode SFP modules. The most common multimode SFP transceiver module is the 1000BASE-SX SFP, with a maximum transmission distance of 550 meters and a transmission rate of 1.25 Gbit/s.

Single-mode SFP modules: These are SFP modules used with single-mode fiber. Single-mode fiber has a small core diameter and is designed to transmit a single mode of light. The intermodal dispersion of single-mode fiber is much narrower than that of multimode fiber, thus supporting higher bandwidth and typically used in long-distance networks. The 1000BASE-LX, 1000BASE-EX, 1000BASE-EZX, BiDi SFP, CWDM SFP, and DWDM SFP are all single-mode SFP transceiver modules.

3.What is The Difference between Copper SFP and Fiber SFP?

SFP modules are general-purpose optical modules compatible with various fiber optic communication standards, including single-mode and multimode fiber. They are commonly used to connect switches, routers, and other network devices, providing high-speed fiber optic communication. A key feature of SFP modules is their hot-swappable capability, allowing users to replace different types of SFP modules to meet varying network needs. Factors to consider when selecting an SFP module typically include speed, whether it's single-fiber bidirectional or dual-fiber, and transmission distance.

RJ45 copper SFP modules are designed for copper cabling (such as Cat5e or Cat6). They convert fiber optic ports to copper ports, allowing devices to connect via traditional Ethernet cables. These modules are typically used for short-distance data transmission, such as within data centers or offices. Currently, they are primarily used for transmitting lower-speed data, such as 1G or 10G.