Nowadays, more and more people intends to utilize fiber optic link in networking system for the reason that it covers wider range of distance, provides higher bandwidth and comes with less signal interference and so on. Moreover, it even can be accessed easily in some PoE devices, such as PoE fiber switch, which generally equipped with one or two SFP ports. As it is known that PoE fiber devices are electronics, requiring power supply while fiber is plastic or glass material that can’t conduct electric currency to your front-end IP devices. Therefore you can’t connect the fiber optic cable straightly to the fiber ports, because these ports are empty and lack of signal conversion tools. That means you requires tools can help finishing signal conversion.
Well for every problem there is a solution, and that solution is the SFP modules, also called SFP transceiver. Now before going in any further, let me tell you what is a SFP, the SFP is a compact, hot-plugged transceiver used for data communication application, which allows metal devices plug into a unique switch slot and support communication networking cable.
Now there are various of SPF modules available in the market, to use which types of SFP modules may depend on different requirements or demands, such as fiber cable type, connection distance, connector types, network speed etc. The following content might be helpful to you if you want to choose the right SFP module that suits your PoE fiber devices.
You should figure out which types of fiber optic cable you are going to use. Fiber optic cables can be divided into single mode and multi-mode fiber optic cable. Choosing which types generally depends on the distances you want to reach. Majority of people or business use single mode. fiber optic cable to reach longer transmission distance. While multi-mode fiber optic cable commonly use for data communication with short distance, such as data centre. Make clear of one thing, are you looking for the short range or a long range transmission? Therefore, you will know you need to choose multi-mode SFP transceiver or the single mode one.
As mentioned previous, the single mode has a further range, and can transmit anywhere from 2km all the way to 80km in distance, but just to remind you that the standard single mode can transmit up to 10km, while the extended single mode is up to 80km, so if you are looking for a long range SFP, then the single mode SFP might just be for you, if you don’t mind the cost being pricy. Unlike the single mode SFP, the multi mode SFP is quite the opposite, it’s a cheaper option to be honest with you, and it is mainly used for shorter distance, a standard multi mode can transmit up to 500m, while the extended multi mode can transmit up to 2km, it’s a great solution if you are looking for a short range transceiver.
Additionally, there is a special type called BiDi SFP transceiver. It differs from the common SFP, which is designed with two ports, that means you need to use two cable to finish conversion of transmitting and receiving, while BiDi only use one cable to accomplish the job.
Another factor to consider is the SFP data rate, in a way it’s basically saying what speed does your network need. Both single and multi mode SFP are virtually identical in size and appearance, but the single mode SFP can be seen as a an upgrade version of the multi mode SFP that supports higher speed up to 10Gbps, this kind of SFP transceiver also called SFP+, while the multi mode SFP supports a speed only around 1Gbps. So while installing make sure that you cannot plug an multi mode SFP into a signal mode SFP port because of the speed requirements.
This bring us to our last two factors that I will give you a brief intro. Some specific fiber PoE device has its own compatibility to the SFP module, if you find it hard to understand then see it as protocols you are require to follow or be aware of. Now big major manufacturers like Cisco advertise that only the SFP modules with their brand can work with their devices. It’s a good choice for using the official SFP module, but the expenses on the other hand is jaw breaking, but here are some things to be aware of. Expect for those specific bands with their own protocols, there is one type SFP module is used the generic protocol. The kind of SFP modules can work compatibly with majority of fiber devices or fiber PoE devices.
Besides considering that, as SFP module works in pair, one for transmitting(TX), the other for receiving(RX), they comes with different wavelength. So you are supposed to ensure that the SFP module have the identical wavelength at either end, ensure both ports are compatible with the SFP module that you choose, these steps might seem troublesome but it sure will provide you a better understanding of the SFP modules. 850nm/1310nm/1550nm,ect, these are commonly used wavelength for SFP, it may seem like just numbers but you must not ignore them, they do represent different range that they can cover, so it would be wise for you to get a good knowledge before making your decision.
The last factor is something you might not even think about, it may not even cross your mind. Well it’s the operating temperature, due to the fact that not all of the SFP has the same work environment, it may be outdoors or indoors, so the operating temperature should be suitable for the different work environment. At outdoor application, withstanding ultra low or high temperature is basic feature in terms of SFP module.
I hope that the following above can share some light so that you can have some knowledge when you choose the right SFP module that is suitable for you.