Singlemode fiber types: Ultimate Guide to Differ Them Apart


Fiber optic cables come in different types according to their application. But when it comes to their transmission mode, the categorization is clear: multimode or singlemode. Although multimode fiber optic types are well known and easy to differentiate, Singlemode fiber types are a bit trickier. Nevertheless, everything counts from the discussion.  

Table of Contents

1. How to Tell a Multimode from a Singlemode Fiber Cable Apart

Many things differentiate multimode and singlemode fiber types apart.  Let’s have a look.

Fiber Construction

Although the cable width is 125 µm in both multimode and Singlemode fiber types, the core diameter is different. Generally speaking, in multimode ones, core diameter ranges from 50 µm to 62.5 µm, depending on the model. However, in Singlemode fiber types, the core diameter is usually 9 µm. The Singlemode fiber core is narrow, so, the light passes through it without reflecting repeatedly. Thus, the light attenuation is on low levels, ranging from 0.22 dB/km to 0.36 dB/km.


As you know, color is the easiest way to differentiate them from one another. After all, multimode fiber optic cables usually have aquamarine or orange sheath, while single mode ones have a yellow cover.


Also, the cost is a sensitive issue, because it differs according to its transceiver, system, and installation prices. While it only has a $1 difference in 1Gb-speed compatible transceivers, it reaches up to $400 on 100Gb-speed compatible devices. Also, although the actual cable cost is usually low, the Singlemode system costs up to 5 times more than a multimode. However, for the installation, it’s cheaper to install a Singlemode fiber than a multimode one due to its long-distance runs.


Furthermore, multimode fiber optic allows light to reflect and bounce multiple times in its core, while single-mode ones send only a single light source through it. So the bandwidth is more stable on Singlemode fibers than multimode ones. 

Fiber Distance

As you now know, multimode fiber works on short-distance runs while singlemode fiber cable works on long-distance ones. But exactly, how much of a difference is there between the two categories? Multimode fiber cables cover from 70m to 550m on 1Gb/s to 100Gb/s connections. Singlemode ones, on the other hand, cover up to 10Km on 1Gb/s to 10GB/s connections.

2. OS1 vs OS2

Generally speaking, the difference between OS1 and OS2 fiber optic cables is mainly in cable construction. Then what difference can the construction make? 

OS1 Single Mode Tight Buffered Cable

Commonly used on distances no longer than 2Km, OS1 singlemode fiber cables are perfect on 1 to 10Gb Ethernet connections. In addition, OS1 cables have a maximum attenuation of 1.0dB/km in all 1310 nm, 1383 nm, and 1550 nm wavelengths. Operators use them preferably indoors, as they offer tighter and sturdy support to the fiber.

OS2 Single Mode Loose Tube Cable

On the contrary, OS2 Singlemode cables’ loose tube feature puts less pressure on the actual fiber in the core. Also, they work wonders on distances that go from 5 to 10Km on 1 to 10Gb-speed connections. OS2 cables have a maximum attenuation of 0.4dB/km in all 1310 nm, 1383 nm, and 1550 nm wavelengths. Thanks to their loose tube construction, OS2 cables work for outdoor installations.

3. Cross Reference To International Standards

Depending on where you are in the world, there are various ways to designate singlemode fiber types. First, the ISO joined IEC and used ISO/IEC 11801 and TIA-568 for optical fiber specifications. In addition, the TIA/EIA works primarily with optical fiber and system test standards, using their own nomenclature. Finally, the ITU administers single-mode fiber standards documents, using G.652 through G.655 standardized nomenclature.

DescriptionITU-T RecommendationIEC 60793-2-50:2015TIA
Dispersion-unshifted singlemode optical fibersG.652
Dispersion-shifted singlemode optical fibersG.653
Cut-off shifted singlemode optical fibersG.654
Non-zero dispersion-shifted singlemode optical fibersG.655B4(Formerly 492E000 sectional specification)
Wideband non-zero dispersion-shifted singlemode optical fibersG.656B5492CAAC (Formerly N/A)
Bending loss insensitive single-mode optical fibersG.657B6

Now, you must have a clear picture of singlemode fiber types. With its own pros and cons, singlemode fiber is in application for almost everything. As usual, for more information or help with all kinds of cable assemblies, contact us.