Same as single-mode and multimode fiber

Single-mode fiber transmits light along a single path for long distances and high bandwidth, while multimode fiber allows multiple light paths, suitable for shorter distances and lower cost deployments. Core Design and Light PropagationSingle-mode fiber (SMF) has a very small core diameter, typically around 9 µm, allowing only one mode of light to propagate straight through the fiber. This minimizes modal dispersion and enables long-distance, high-speed transmission.

Multimode fiber (MMF) has a larger core, usually 50 µm or 62. 5 µm, which allows multiple light modes to travel simultaneously. The multiple paths cause modal dispersion, limiting the effective transmission distance and bandwidth.

Light Source and WavelengthSMF typically uses laser light sources at wavelengths of 1310 nm or 1550 nm, optimized for long-distance communication.

MM

F commonly uses LEDs or VCSELs at 850 nm, with some legacy applications at 1300 nm. The larger core makes it easier to couple light from these sources. Bandwidth and Transmission DistanceSMF supports higher bandwidth and can transmit data over tens to hundreds of kilometers without significant signal loss, making it ideal for backbone networks and long-haul links.

MM

F is suitable for shorter distances, typically within buildings or data centers, due to modal dispersion that limits bandwidth over long runs. Cost and InstallationSMF cables and transceivers are generally more expensive and require precise handling due to the small core size.

MM

F is easier to install and terminate, with lower initial costs, making it cost-effective for local networks and short-reach applications. Typical ApplicationsSingle-mode fiber: Long-distance telecommunications, high-speed backbone networks, and future-proof infrastructure. Multimode fiber: Short-distance connections in data centers, enterprise LANs, and campus networks where cost and ease of installation are priorities.

Summary

The core difference lies in the number of light modes each fiber supports: SMF allows a single mode for long-distance, high-bandwidth transmission, while MMF supports multiple modes for shorter distances and lower-cost deployments. Choosing between them depends on distance, bandwidth requirements, budget, and future network expansion plans.