Fiber optic cables (being they multimode or single mode, depending on the communication requirements) provide a safe environment for an effective transmission of data. But if the distance is a factor that must be taken into account, a fiber mode conversion from multimode to single mode (MMF to SMF) is required. So, what is there to know and do?

Read on to find out when, how, and why do you need fiber conversion.


First, let’s talk a little bit about multimode and single mode cables

multimode and single mode

The main thing everyone should understand is the difference between single mode and multimode patch cords. Single mode cables are meant for long distance, while multimode is often used for shorter distances.

Single mode cables are designed to carry light directly down the fiber. It is a single strand of glass fiber and has a diameter of 8.5-10 microns. Because it has one mode of transmission, it will propagate 1310 or 1550 nm.

Compared to the multimode fiber, the single mode patch cords carry a higher bandwidth, but it requires a light source with a narrow spectral width. The single mode gives a higher transmission and up to 50 times more distance than the multimode. The core from a single mode cable is smaller than one from a multimode.

Multimode patch cords have a bigger diameter, typically 50-100 microns for the light carry component. Over medium distances, multimode fibers give high bandwidths at high speeds. Light waves are dispersed into numerous paths, or modes, as they travel through the cable’s core typically 850 or 1300nm.

In cable runs longer than 914,4 meters, the multiple cable pats can cause distortion at the receiving end, resulting in an unclear and partial data transmission.


When is the conversion required?

Here’s one thing everyone should understand: a fiber optic network doesn’t imply solely the use of a single type of fiber, but, in most cases, it requires mode conversion during transmission, especially MMF to SMF.

If the network distance outpaces the limit of multimode fiber, or in function of the network’s connectivity type and the equipment’s specifications (f.e. an office building has only multimode appliances and the connection to the provider is single mode), then a way of converting needs to be found.


How to convert?

At this moment, there are three ways of converting multimode to single mode.

  1. Fiber to Fiber Media Converter

A fiber to fiber media converter can boost a multimode network over to single mode fibers with distances of up to 140 km.

  1. Mode Conditioning fiber patch cord

The Mode Conditioning fibre is not able to transform signals into electrical impulses, but it launches the laser light from the center of the MM fiber. The laser disperses across the core, reducing in this way the DMD (differential mode delay).

  1. WDM Transponder

Similar to the previous two mentioned solutions, the WDM Transponder is able to convert MM to SM. The transponder is often used in DWDM; both MMF to SMF and SMF to MMF conversions can be accommodated.


PeakOptical’s solutions

PeakOptical offers a wide range of solutions for any fiber optic network. You can consult our list of converters here or you can take a look at all our product categories here. If you are not able to identify a solution yourself from our website, please contact our team and we’ll put together a personalized solution.




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