Analysis of Transmission Distance and Rate of SFP Optical Modules
SFP optical module is a small, hot swappable optical communication module used in fiber optic networks. Its transmission distance and speed are affected by various factors, and this article will analyze these two aspects.
1, Transmission distance
The transmission distance is determined by the type, wavelength, and module design of the optical fiber. Single mode optical modules (wavelength 1310nm or 1550nm) utilize the low loss characteristics of single-mode optical fibers (core diameter 9 μ m) to support long-distance transmission. Typical scenarios include: 1.25Gbps modules can reach 20km to 100km, 10Gbps modules cover 10km to 40km, and 25Gbps modules can achieve 10km to 40km.
Multimode optical modules (wavelength 850nm) rely on multimode optical fibers (such as OM3/OM4), but due to large dispersion, the distance is significantly limited: 1.25Gbps only supports 300m to 550m, 10Gbps is limited to 300m, and 25Gbps is further reduced to 70m (OM3) or 100m (OM4). For example, the Huawei SFP-10G/25G-SR module achieves 25Gbps and 70m transmission on OM3 fiber, while the TP-LINK TL-SM311LS single-mode module has a stable connection of 1.25Gbps and 20km at a wavelength of 1310nm.
2, Speed range
The speed coverage of SFP optical modules ranges from 100Mbps to 25Gbps, depending on the module type and application scenario. Ordinary SFP modules support 100Mbps to 1.25Gbps (such as Gigabit Ethernet) and are suitable for basic networks; SFP+modules are designed specifically for 10Gbps to meet 10G requirements; The SFP28 module is further expanded to 25Gbps or 32Gbps, suitable for high-speed data centers. The increase in speed often accompanies a reduction in transmission distance, as high bandwidth requires higher signal integrity and better fiber and wavelength schemes need to be matched.
