Many people encounter a core question when setting up a network: should I use multimode fiber or single-mode fiber? Today, ETU-LINK will thoroughly explain the differences between the two to help you make the most economical and efficient choice.

I. Core Principle: Different Light Transmission Methods

As the name suggests, "mode" refers to the path pattern of light propagating in an optical fiber.

In single-mode fiber (SMF), light propagates along a single path, and the light source uses a laser to produce a highly concentrated, directional beam.

Multimode fiber (MMF) light propagates in multiple paths, with a transmission distance generally less than 2km. The light source uses light-emitting diodes (LEDs), and the light has a large divergence angle.

Multimode Fiber: with a core diameter of 50μm-100μm, operating wavelengths of 850nm or 1310nm, and relatively easy to couple with optical devices. It can transmit multiple modes at a given operating wavelength.

Multimode fiber can support longer transmission distances. Common multimode fiber core diameters are 50μm and 62.5μm.

II. Key parameter comparison

To help you understand this more clearly, we have created the following comparison table:

III. How to choose? It depends on the situation!

There is no absolute superiority or inferiority between multi-mode and single-mode; the key lies in the application requirements.

(1). Scenarios requiring multi-mode selection:

• Inside the data center: For connections between server racks and between floors (distance ≤ 400 meters), OM3/OM4 multimode fiber with 100G QSFP28 SR4 module is recommended.

• Enterprise LAN: Short-distance cabling within office buildings and industrial parks, with controllable costs and convenient construction.

• Storage Network (SAN): Short-distance, high-speed interconnect scenarios such as 32G Fibre Channel.

• Existing multimode cabling upgrade: Smooth capacity expansion can be achieved through compatible modules (such as 40G QSFP+ SR4).

(2). Scenarios for menu mode:

• Metropolitan Area Network/Backbone Network Construction: Long-distance transmission across cities and regions (such as 10G SFP+ 120km module with OS2 fiber).

• 5G base station backhaul: Scenarios requiring stable transmission over distances exceeding 2km.

• Data Center Interconnect (DCI): Long-distance data backup and synchronization, supporting 100G LR4/ER4 and other modules.

• Industrial applications: For long-distance communication in harsh environments, industrial-grade (-40℃-85℃) single-mode modules can be selected.

IV. Professional Advice from ETU-LINK

The basic principle is to use multi-mode for short distances and single-mode for long distances. However, for intermediate ranges (such as 500 meters to 2 kilometers), it is necessary to comprehensively consider current costs and future plans.

ETU-LINK Optical Communication, as a professional module manufacturer, can provide 1G-400G optical modules, fiber optic cables and other products. Welcome to purchase!