Introduction to Single-mode Fiber Patch Cable

As we all know, fiber optic patch cable plays a vital and significant role to achieve connectivity between optical equipment in telecommunication field. According to different fiber core diameter, there exist two types of fiber patch cords—multimode fiber (MMF) patch cables and single-mode fiber patch cable. In my previous blogs, I have discussed some information about multimode fiber patch cable, including its definition, types and applications. How about single-mode fiber (SMF) patch cable? Do you really know enough about it? Read this article, and you will get a comprehensive understanding of it.

Features of Single-mode Fiber Patch Cable

Single-mode fiber patch cable contains a small core of 9/125 microns which is designed to support only one pathway of light. Instead of simply bouncing the light of the edge of the core, the single-mode patch cable realigns the light toward the center of the core with only a single wavelength of light passing through its core. Like multimode optical cable, single-mode patch cable does exhibit modal dispersion resulting from multiple spatial modes but with narrower modal dispersion. Therefore, single-mode patch cable is better at retaining the fidelity of each light pulse over longer distances than multimode patch cable. Generally, single-mode fiber patch cable is more expensive than multimode patch cable, but it offers better performance and is more cost-efficient in long run transmission. Besides, the color of single-mode fiber patch cable is yellow, while the multimode patch cable is generally orange or aqua. So when you choose a single-mode fiber patch cable, you can easily find the right one from the appearance. Here is a single-mode fiber cable with LC connectors.

single-mode fiber cable

Two Single-mode Fiber Patch Cable Types

Like multimode-fiber patch cable with OM1, OM2, OM3 and OM4 types, single-mode fiber patch cable can be categorized into OS1 and OS2. That is, OS1 and OS2 are cabled SMF specifications. OS1 and OS2 are standard single-mode optical cables respectively used with wavelengths of 1310 nm and 1550 nm with a maximum attenuation of 1 dB/km and 0.4 dB/km. Besides these two aspects of differences, the following part will tell the differences between OS1 and OS2 from perspectives of standards and cable construction.

First introduced in the year of 2002, OS1 refers to a very old specification for SMF. The mechanical, optical and environmental characteristics of OS1 are compliant with ITU-T G.652A or ITU-T G.652B standards. Additionally, the low water peak fibers categorized in ITU-T recommendations as G.652C and G.652D also come under OS1 fibers. Thus, OS1 is a general term used to specify single-mode optical cable that comes under the heading of ITU-T G.652. In contrast, OS2 was introduced in 2006. Only ITU-T G.652C and G.652D comes under OS2 fibers which means that OS2 SMF is low water peak fiber only.

Another main differences between OS1 and OS2 SMFs is the cable construction. Typically, OS1 cabling is tight-buffered which is suitable for indoor applications, such as campus or data center, while the OS2 cabling is loose-tubed which is available for outdoor use, like street, underground or burial.

There are many other differences between OS1 and OS2 SFMs, such as performance, transmission distance and cost, etc. The maximum distance of OS1 SMF is 2 km while the transmission distance of OS2 is 5 km and is up to 10 km. The following table shows OS1 and OS2 specification differences.


Single-mode fiber patch cable supports advanced network applications required in data centers, enabling guaranteed performance for Gigabit applications. We have mentioned the features, two SMF types and their differences, and you may get some basic information about this type of fiber patch cables. Hope you can choose the right one for you network.


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