Difference between single mode and multimode sfp

 
Single Mode SFP and Multi-Mode SFP are two types of transceiver modules that are used to transmit and receive data in optical fiber networks. They use the same physical design, but they operate differently due to their inherent characteristics and the type of fiber they are used with.

1. Single Mode SFP:

This type of module is used with single mode fiber, which only allows one mode (or path) of light to pass through at a time. Single mode fiber typically has a core diameter of about 9 micrometers and utilizes laser light for transmission. This results in very little signal loss over long distances, so single mode SFPs are typically used in long distance data transmission applications, generally over distances of up to several kilometers to hundreds of kilometers.
Singlemode fiber has much tighter tolerances for optics used. The core is smaller and the laser wavelength is narrower. This means that SMF has the capability to carry a higher bandwidth at much longer transmission distances. Singlemode SFPs work mainly in the 1310nm and 1550nm wavelengths and is mostly used in a long distances transmission environment reaching 2km, 10km, 40km, 60km, 80km and 120km.

2.Multi-Mode SFP:

This type of module is used with multi-mode fiber, which allows multiple modes (or paths) of light to pass through at the same time. Multi-mode fiber typically has a larger core diameter (about 50 to 62.5 micrometers) and utilizes LED light for transmission. This results in more signal loss due to dispersion, but also allows for a higher bandwidth capacity. Thus, multi-mode SFPs are typically used in short distance data transmission applications, generally less than 2 kilometers.
Multi-mode fiber uses a much bigger core and usually uses a longer wavelength of light. Because of this, the optics used in Multi-mode have a higher capability to gather light from the laser. In practical terms, this means the optics are cheaper. The common Multi-mode SFPs work in 850nm wavelength and is only used for short distance transmission reaching 100m and 500m. Though it’s not able to transport for long distance, it can transport many kinds of optical signals.

Here are the main differences between Single Mode SFP and Multi-Mode SFP:

1. Operating Wavelength:

 Single mode SFP typically operates at 1310nm or 1550nm, while multi-mode SFP typically operates at 850nm.

2. Transmission Distance:

 Single mode SFP can support longer transmission distance (up to several kilometers or even hundreds of kilometers), while multi-mode SFP is suitable for short distance (generally less than 2 kilometers).

3. Fiber Cable:

Single mode SFP is used with single mode fiber cable (usually yellow), while multi-mode SFP is used with multi-mode fiber cable (usually orange or aqua).

4. Cost:

 Single mode SFP is typically more expensive than multi-mode SFP due to the more complex technology required for long distance transmission.
It's important to choose the appropriate SFP module based on your specific networking needs, considering factors such as transmission distance, cost, and available fiber infrastructure.

Warm Tips

As we know, single mode and multimode are not interchangeable. The main reason is the wavelength of the laser and core size of the fiber. However, take Cisco SFP for example, there is a type of the GBIC SFP module (part number “SFP-GE-L” or “GLC-LH-SM“) which can support both single mode and multimode fiber. But a mode-conditioning patch cord is required when using the SFP-GE-L or GLC-LH-SMD with 62.5-micron diameter MMF. You must install a mode-conditioning patch cord between the GBIC module or SFP module (view GBIC vs SFP) and the MMF cable on both the transmit and the receive ends of the link when link distances are greater than 984 ft (300 m). In this case, Cisco does not recommend using the SFP-GE-L or GLC-LH-SM and MMF with no patch cord for very short link distance (tens of meters). The result could be an elevated bit error rate (BER). Actually, other brands, like Brocade, also can offer a similar SFP module.
When we choosing the SFP module, we must confirm the transmission distance and wavelength we want to use it. This will help us to choose the right SFP types more efficiently. In addition, the costs for transceiver modules which keep adding up over time will be a budget pressure for many users. To save more, we can choose the compatible module without sacrificing any quality or reliability but only at a low cost. Fiberstore, an excellent supplier, supplies 100% compatible fiber optic transceiver modules of many brands, such as Cisco, HP, Juniper, Brocade, etc. with an incredible discount that may be a good choice for you.
 

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How to buy And Use Single Mode SFP & Multimode SFP?

When we buying single mode SFP or multimode SFP in the market, we must confirm the transmission distance and wavelength we need. This will help us to choose the right SFP types more efficiently. The cost for transceiver modules is also a significant factor considered by many users. Well, the compatible SFP module should be recommended as a simple and convenient choice. Because it not only sacrifices no quality or reliability but also has a low cost. Hope these tips could help you make an informed decision.

Figure 2: how to buy single mode & multimode SFP

Tips on using Single Mode SFP & Multimode SFP
Single mode SFP and multimode SFP modules are both used in the switch slot and support communication over either fiber optic or copper networking cable. When you use single mode SFP or multimode SFP, you’d better keep these tips in mind:
· Make sure that SFPs in both ends of the fiber patch cord are of the same wavelength and consistent in color coding.
· To ensure the data accuracy, short-wave SFP modules are generally utilized with multimode fibers (ie. orange fiber patch cord), while long-wave SFP modules with single mode fiber (ie. yellow fiber patch cord).
· Protect the optical port by dust plug when not using the SFP.

Single Mode SFP vs Multimode SFP：Which One to Choose?

After the comparison of single mode SFP vs multimode SFP, we can see that single mode SFP is suitable for long-reach data transmission applications while multimode SFP is generally utilized for short transmission distance. Which to choose depends on the actual needs. FS supplies various kinds of optic transceivers available in both single-mode and multimode. If you have any needs, welcome to visit FS.COM.