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How to tell the difference between single mode and multimode fiber?
Knowledge Base + 2023.12.08

Distinguishing between single-mode and multimode fiber optic cables can be done by considering several factors. Here are some methods you can use:

  1. Core Diameter:

    • Single-mode (SM): Typically has a smaller core diameter, usually around 9 microns. This allows for a single mode of light to travel through the core.

    • Multimode (MM): Has a larger core diameter, commonly either 50 or 62.5 microns. It allows multiple modes (paths) of light to propagate through the core simultaneously.

  2. Color of the Jacket:

    • Single-mode: Often has a yellow jacket, but this is not a strict standard. Blue jackets are also used in some cases.

    • Multimode: Can have different jacket colors, such as orange for 62.5 micron and aqua for 50 micron. However, this can vary depending on the manufacturer.

  3. Bandwidth and Data Transmission:

    • Single-mode: Offers higher bandwidth and is suitable for long-distance transmissions. Commonly used in applications like long-distance telecommunications and data centers.

    • Multimode: Has lower bandwidth but is suitable for shorter-distance transmissions. Commonly used in local area networks (LANs) and short-distance data communications.

  4. Light Source:

    • Single-mode: Typically uses a laser as the light source due to its narrow core diameter.

    • Multimode: Uses LEDs (Light Emitting Diodes) or lasers depending on the application. LEDs are often used for short distances, while lasers are used for higher bandwidth and longer distances.

  5. Connector Types:

    • Single-mode: Commonly uses LC, SC, or MTP/MPO connectors for higher-density applications.

    • Multimode: Commonly uses SC, ST, or MTP/MPO connectors. LC connectors are also used, especially in high-density environments.

  6. Distance:

    • Single-mode: Suitable for long-distance transmissions, often ranging from several kilometers to tens of kilometers.

    • Multimode: Suitable for shorter distances, typically up to a few hundred meters, depending on the specific type (e.g., OM1, OM2, OM3, OM4).

When in doubt, checking the cable specifications, looking at the color, and knowing the intended application can help you identify whether a fiber optic cable is single-mode or multimode.

What is an SFP Transceiver Modules

An SFP, Small form-factor pluggable, is a compact and hot-swappable transceiver used to connect a switch or other network device to copper or fiber cable. SFP replaces the formerly common gigabit interface converter (GBIC), and SFP is also called Mini-GBIC. The SFP ports on a switch and SFP modules enable the switch to connect to fiber and Ethernet cables of different types and speeds. The small formfactor pluggable, SFP, specification is based on IEEE802.3 and SFF-8472. Almost all enterprise-class switches include two or more SFP ports, enabling them to become part of a ring- or star-based network topology spread among different buildings, floors or areas, connected via fiber optic cabling.

How does an SFP port work?

An SFP port connection enables the transfer of data between two devices via an SFP transceiver and appropriate cabling. In other words, the port and its corresponding SFP transceiver allow the two devices to communicate with each other over an extended distance.

What is an SFP port used for?

SFP ports and their corresponding SFP modules are used to facilitate seamless, high-speed data communications or telecommunications connections over extended distances in a variety of applications.They're often used to connect a one-gigabit network switch to another, which, in turn, increases the size and improves the functionality of a network. This is helpful in military, industrial, and commercial settings where numerous devices in a widespread area require a wired, high-speed, reliable connection.

How to Choose an Ethernet SFP Module?

Choose SFP Copper or Fiber Module?

SFP module comes in various types on the basis of different classification standards. It works with copper Ethernet cables or fiber optical cables.

On the fiber optics side, there are single mode SFP module and multimode SFP module, which allows users to select the appropriate transceiver according to the required optical range for the network. Operation wavelength ranges from 850nm to 1550nm. Commonly, 850nm SFP can reach up to 550 meters with multimode fiber optics, and the 1550nm SFP supports up to a maximum of 160km via single mode fiber cables. On the other hand, copper SFP modules primarily are 1000BASE-T SFP and 1000BASE-TX SFP modules, which are excellent used in gigabit Ethernet networking within 100 meters.

Choose SFP or Advanced SFP+?

SFP and SFP+ are applied at different transmission speeds. SFP module supports 1Gb data rate, and the SFP type includes 1000base-T/TX, 1000base-SX, 1000base-LX/LX10, 1000base-BX10, 1000base-LX/LH, 1000base-EX, 1000base-ZX and so on.

SFP+ is used in 10-gigabit Ethernet applications but shares the same form factor with SFP. In the SFP+ family, there are primarily SFP+ SR, SFP+ LR, and SFP+ ZR modules for 10 Gigabit ethernet networking.

Choose an MSA Compatible SFP or Not?

Compatibility is often the most important parameter users care about when buying an MSA SFP module. MSA (multi-source agreement) is an agreement supported by a number of manufacturers who came together to collaborate and standardize the fit-form and try to provide a reliable mean of mixing and matching SFP brands successfully. Third-party companies also have developed their own tools to program SFP modules to be compatible with the OEM. So, the MSA compatibility Gigabit SFP module can be used successfully in most networks.

SFP vs. SFP+

Here is a table of comparison between SFP and SFP+




Stands for

Small Form-factor Pluggable

Small Form-factor Pluggable plus (standard form)

Data rate







Dual fiber

Single Fiber/WDM



Dual fiber

Single Fiber/WDM