Distinguishing between multimode (MM) and single-mode (SM) fiber optic cables can be done through visual inspection and consideration of certain characteristics. Here are some methods: 

1. Core Diameter:

• Single-mode (SM): The core diameter is smaller, typically around 9 microns.

• Multimode (MM): The core diameter is larger, commonly 50 or 62.5 microns.

2. Color of the Cable:

• Single-mode: Often has a yellow outer jacket, but blue is also common. The color-coding may vary, so it's not always a reliable indicator.

• Multimode: Can have various jacket colors, such as orange for 62.5 micron and aqua for 50 micron. Again, color coding can vary, and it's not a strict standard.

3. Bandwidth and Data Transmission:

• Single-mode: Offers higher bandwidth and is suitable for long-distance transmissions.

• Multimode: Has lower bandwidth and is typically used for shorter-distance transmissions within a building or campus.

4. Light Source:

• Single-mode: Generally 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 shorter 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).

It's important to note that visual inspection might not be foolproof, especially if the cable jackets are not color-coded according to the typical conventions. In such cases, referring to cable documentation or contacting the manufacturer for information about the cable can help confirm whether it is single-mode or multimode. Additionally, you can use specialized tools such as a fiber optic microscope or a light source and power meter to characterize the fiber more precisely.

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+