Comparison Between
OS1 and OS2 SMF Cables

Single mode fiber cable is categorized into OS1 and OS2 fiber cable. These two kinds of fiber cables have different characteristics for diverse applications. OS2 SMF cables can not be connected with OS1 SMF cables, which may lead to poor signal performance. Therefore, it’s of great significance to figure out the difference between OS1 and OS2 when conducting deployments. Follow with this article to classify OS1 vs OS2.
 
OS1 vs OS2 SMF Cables, What Are Their Differences?
Standard
OS1 SMF cables are compliant with the specifications of ITU-T G.652, including ITU-T G.652A and ITU-T G.652B standards (conventional), ITU-T G.652C and G.652D standards (low-water-peak). However, OS2 SMF fiber cables are only compliant with ITU-T G.652C or ITU-T G.652D standards that are specifically applied to the low-water-peak fibers. These low-water-peak fibers are usually used for CWDM (Coarse Wavelength Division Multiplexing) applications. A new standard—G.657.A1 standard has published for bend-insensitive SMF cables for optimized performance and cost balance, some of the OS2 SMF fiber cables are accord with this standard.
 
Cable Construction
Embedded in a heavy polymer jacket, the OS1 cable is suitable for tight-buffered construction of indoor applications. For indoor applications, the jacketed fiber is generally enclosed, with a bundle of flexible fibrous polymer strength members like aramid in a lightweight plastic cover to form a simple cable. Whereas the OS2 cable is predominantly of a loose-tube construction, which is more appropriate for outdoor cases. A much more robust cable construction is required when deploying in some strenuous environments. The OS2 SMF is laid helically into semi-rigid tubes, allowing the cable to stretch without stretching the fiber itself in order to protect the fiber from tension.
 
Attenuation
The attenuation of an OS1 fiber cable is higher than an OS2 fiber cable. Typically speaking, the maximum attenuation of OS1 is 1.0db/km for 1310nm and 1550nm, while the numerical value of OS2 is 0.4db/km for 1310nm and 1550nm. Consequently, the maximum transmission distance of OS1 single mode fiber is 10 km, while the maximum transmission distance of OS2 single mode fiber can reach up to 200 km. Both OS1 and OS2 single mode fibers will allow speeds of 1 to 10GbE with varied transmission distances. Furthermore, the OS2 type of single mode fiber optic cable can be applied for 40G/100G Ethernet connections.
The specification table below will present the differences between OS1 and OS2 clearly.
OS1 vs OS2 SMF Cables, How to Select?
When it comes to the cable selection between OS1 and OS2 single mode fiber, it’s essential to be clear that you are adopting these SMF cables for long-haul transmissions. Choose the proper cables based on your link length requirements.
OS1 optical fiber cables are applied for indoor network infrastructures, which are mainly deployed in internal building/campus networks, as well as internal cabling within telecommunication exchanges and data centers. Then OS1 cables are fit for your indoor application demands. OS2 optical fiber cables are more appropriate for outdoor and universal loose tube solutions, which would include external plant and most backhaul networks. When it is needed for outdoor network infrastructure, then OS2 is the way to go.
Why Should We Use OS2 Over OS1 Fiber?
After comparing the two fiber cables, it can be concluded that OS2 is more suitable for long-haul transmission by offering better performance with fewer losses. Considering this, why not adopt the optimal OS2 solutions to create a better performance for today’s high-speed data networks?
 
In fact, OS1 used to be the only one standard for single-mode fiber with the maximum link length for campus cabling around 10 km, which can no longer satisfy people’s increasing needs for longer link lengths. The OS2 single mode fiber optic cables are ideal for connecting 1G/10G/40G/100G Ethernet connections, meeting the requirements of high performance with long distances. As a result, more and more vendors tend to provide solutions with OS2 SMF cables for modern network applications.

OS1 And OS2 SMF Fiber Expalin Style 2

What is OS1 Fiber?

OS1 fiber generally refers to single-mode fiber that adheres to the ITU-T G.652A and ITU-T G.652B standards (conventional). Additionally, low water peak fibers falling under ITU-T G.652C and G.652D are also considered part of OS1. This tightly buffered fiber boasts a 1.0 dB/km attenuation, making it suitable for short-distance transmissions in indoor environments, typically up to 2 km under 10 Gigabit Ethernet. As an older legacy fiber, OS1 has lower performance requirements compared to OS2, making it easier and more cost-effective to manufacture.

What is OS2 Fiber?

OS2 fiber is single-mode low-water peak fiber, complying with ITU-T G.652C and ITU-T G.652D specifications. In practical applications, OS2 fiber often refers to G.652D, as G.652A and G.652B fibers have high attenuation characteristics unsuitable for 1383nm transmission. G.652D fiber overcomes this limitation, enabling full-spectrum transmission with low attenuation in this band.

The outstanding performance of OS2 fiber makes it ideal for full-band CWDM and DWDM applications, maximizing fiber utilization. With a maximum attenuation of 0.4dB/km, it excels in long-distance outdoor transmission, supporting network throughputs of up to 100 Gbit/s over distances of approximately 200 km. Its superior characteristics make OS2 fiber a powerful choice for high-performance and high-capacity fiber optic networks.

OS1 vs OS2 Fiber, What is the Difference?

Now, let’s take a quick look at the differences between single mode fibers. The comparison chart below simplifies the key distinctions.

ComparisonOS1OS2
ITU-T G.652 StandardsITU-T G.652A/B/C/DITU-T G.652C/G.652D
Cable ConstructionTight BufferLoose Tube
ApplicationIndoorOutdoor
Attenuation1.0dB/km0.4dB/km
Wavelength1310nm, 1550nm1310nm, 1383nm, 1550nm
Max. Distance10 km200 km
PriceLowHigh

S1 vs OS2 Fiber, How to Choose?

  • Application
    OS1 optical fiber cables are specifically designed for indoor network infrastructures, making them an excellent choice for internal building/campus networks, telecommunication exchanges, and data centers.
    On the other hand, OS2 optical fiber cables are better suited for outdoor applications and universal loose tube solutions, including external plant and most backhaul networks. For outdoor network infrastructure needs, OS2 is the preferred option.
  • Distance
    OS1 single mode fiber can achieve a maximum transmission distance of up to 10 km, while OS2 can cover an impressive 200 km—far surpassing OS1. This substantial advantage makes OS2 the preferred choice in practical fiber optic cabling, especially for long-distance applications where reliable and efficient data transmission is crucial.
  • Cost
    The enhanced performance requirements of OS2 fiber, including lower attenuation and full wavelength support, increase manufacturing complexity, ultimately impacting the cost. As a result, OS2 fiber generally comes at a higher price point compared to OS1 fiber.

FAQ About OS1 vs OS2 Fiber

Q: Is OS2 fiber better than OS1?
A: Yes, in terms of performance, OS2 fiber is superior to OS1. However, OS1 fiber is more cost-effective and still suitable for certain short-distance applications.

Q: Are OS1 and OS2 interchangeable?
A: No, OS1 and OS2 fibers are not interchangeable. They have different features and parameters tailored for specific applications. Avoid mixing them unless used with a WDM multiplexer.

Q: Can OS1 fiber support 40G & 100G?
A: No, OS1 fiber cannot support 40G and 100G speeds. It has a maximum capacity of 10G.

Q: What is Polarization-mode dispersion?
A: Polarization-mode dispersion (PMD) is a dispersion effect in fiber optics, where light traveling in different polarization directions experiences varying phase speeds, leading to dispersion as the beam travels along the fiber.