When you decide to install fibre optic cables, you have to be familiar with every type, as each serves a different purpose. Similarly, if you are confused about whether to install OS1 or OS2 (single-mode fibre cable types ). Then do remember OS1 is designed for indoor networks and offers ease of use at an economical price. However, OS2 is the best choice when it comes to long-distance outdoor installations due to its minimal signal loss.
So, keep reading this blog as we’ll discuss both types in detail and will clear what’s the differences between them which may save you a lot of time, money, and frustration.
1) Understanding OS1 and OS2 fibre optic cables
i) What is OS1?
“OS1 ( Optical single mode 1 ), is a particular type of single-mode fibre optic cable which is specially designed for indoor applications.”
OS1 fibre cable exhibits tight buffering, indicating that the core fibres are surrounded by protective coverings. Moreover, they are only used for shorter-length data transfer with very little loss of signal.
- Technical Specifications:
| Core Diameter | Cladding Diameter | Wavelengths | Maximum Attenuation | Jacket Type | |
| OS1 fibre cable | 8 to 10 microns | 125 microns | 1310 nm & 1550 nm | 1.0 dB/km for 1310 nm and 1.0 dB/km for 1550 nm | Tight-buffered (for indoor installations only) |
- Uses of OS1 fibre cable:
Due to its low attenuation, OS1 fibre is commonly used in indoor networks that require a higher degree of performance. For instance;
- High-speed connections between servers and networking equipment.
- Internet, phone, and cable TV network connections inside buildings.
- Office LANs (Local Area Networks) for fast internal data transfer.
- Connecting different buildings within a facility or university.
ii) What is OS2?
“OS2 (Optical Singlemode 2) is also another type of single-mode fibre cable that is considered best for outdoor uses and offers high performance for long-distance transmission.”
Unlike OS1, OS2 has a loose-tube structure which contains a fibre core protected by gel or air-filled tubes, giving the fibre greater protection against tough environmental conditions. Thus, data over large distances can be transmitted with very low signal loss using OS2.
- Technical Specifications:
| Core Diameter | Cladding Diameter | Wavelengths | Maximum Attenuation | Jacket Type | |
| OS2 fibre cable | 8-10 microns | 125 microns | 1310 nm & 1550 nm | 0.4 dB/km at 1310 nm, 0.25 dB/km at 1550 nm. | Loose tube ( for outdoor and underground installations ) |
- Uses of OS2:
OS2 fibre optic cables are made for extreme long-range communication and outdoor conditions. For instance; you can use these cables for the following purposes;
- OS2 cables are in great demand in metropolitan and national fibre networks due to their fast and stabilized internet connection.
- OS2’s anti-moisture and anti-temperature features make it ideal for submerged and buried fibres.
- Modern systems for managing traffic lights, surveillance, as well as emergency response systems, mostly use OS2 fibre cables.
- Smart grids use OS2 fibre for communicating power stations and substations.
- You can also use OS2 fibre cables for secure long-lasting easy communication throughout many military and aerospace operations.
2) Key Differences Between OS1 and OS2
Although both OS1 and OS2 utilize light to transmit information, they differ in terms of their structure, performance, and operating environments which makes them more suitable for specific purposes. So, let’s discuss both types deeply!
i) Cable Construction: OS1 vs OS2 fibre cable
- OS1 fibre: It has a tight-buffered design. This means the fibre core is encased in a protective layer, most commonly in the form of a plastic buffer. Such design makes OS1 stronger and more flexible for indoor applications, but it also causes micro-bending (small bends in the fibre that lead to signal loss).
- OS2 fibre: However, OS2 uses a loose-tube design. For instance; it is placed in a hollow tube, which is filled with air or gel. This design allows the fibre to better adjust to environmental conditions such as temperature fluctuations, moisture, and even some level of physical damage.
ii) Performance and Bandwidth: OS2 vs OS1 fibre cable
OS1 and OS2 both have the potential to achieve high-speed fibre optic data transmission, though their efficiencies vary based on the distance. For instance;
- OS1 fibre: This type of cable enables short-distance data transmission up to 10 Gbps within 10 km. However its higher rate of attenuation results in a weaker signal over time.
- OS2 fibre: In comparison, OS2 also allows for 10 Gbps data transmission. However, it can maintain signals for up to 200 km due to lower attenuation.
iii) Distance and Attenuation: OS1 vs OS2 fibre cable
First of all, keep in mind that distance Attenuation refers to the loss of signal power with the distance travelled. Lower attenuation suggests more distance data transmission capability.
- OS1 fibre: OS1 has 1.0 dB/km of attenuation, meaning a 10 km cable would lose 10 dB of signal strength.
- OS2 fibre: OS2’s 0.25 dB/km enables greater efficiency due to the loss being only 2.5 dB over the same distance. This is because OS2’s loose-tube construction and low water peak fibre minimize loss at 1400 nm, making the telecommunication signal highly efficient.
iv) Cost Analysis: OS1 vs OS2 fibre cable
- OS1 fibre: It is more affordable, priced at approximately $0.20 – $0.50 per meter due to ease of fabrication and use in less complex networks.
- OS2 fibre: On the other hand, it is more costly at around $0.50 – $1.50 per meter owing to more complex construction. For instance, OS2 fibres come with additional protective layers because of the advanced manufacturing procedures required to decrease attenuation and enhance durability.
v) Compliance standards: OS2 vs OS1 fibre cable
The OS1 and OS2 optical fibre cables adhere to different industry standards, norms and rules. These standards usually set specific rules for fibre optic construction, performance and safety. Let’s discuss them for OS1 and OS2.
- OS1 Compliance Standards
- ITU-T G.652A/B: The ITU-T G.652A/B specifications describe general single-mode fibres with typical telecommunication network losses. These fibers do possess a higher water peak which causes loss of signal around 1383 nm, thus limiting full-spectrum use. However, it is not a significant problem for short-distance indoor networks.
- ISO/IEC 11801: This standard can be applied to structured cabling systems in buildings. It ensures a coherent approach to data transmission which includes the use of fibre optic, copper and coaxial cables. OS1 fibres are intended to be integrated with enterprise networks with a guarantee so this standard is mandatory.
- EN 50173: This standard is the European counterpart of ISOIC 11801 and covers structured cabling for offices, data centres and industrial sites ensuring network performance throughout Europe.
- TIA/EIA-568: Systems which use OS1 fibres have to meet TIA/EIA-568 standards which guarantee the quality and performance of fixed links, using fibre optic and copper cabling for both data and voice traffic.
- OS2 Compliance Standards
- ITU-T G.652C/D: Through diminished signal attenuation at 1383nm, OS2 fibre’s long-distance data transmission is made possible with the full spectrum, as defined by ITU-T G.652C/D.
- ISO/IEC 24702: These standards set forth symmetric standards for industrial applications of fibre optics that guarantee protection from hostile conditions such as temperature fluctuations and tensile loads.
- EN 60793-2-50: It provides the specifications for the quality and performance of external installation optical fibres.
| OS1 fibre | OS2 fibre | Outcome | |
| Cable Construction | Tight-buffered, strong but rigid | Loose tube, flexible, and resistant to environmental stress | OS2 (Better durability) |
| Performance & Bandwidth | 10 Gbps (short distances) | 10 Gbps (long distances) with lower signal loss | OS2 (Better over distance |
| Attenuation (Signal Loss) | 1.0 dB/km | 0.25 dB/km | OS2 (Lower loss, longer reach) |
| Maximum Distance | Up to 10 km | Up to 200 km | OS2 (Longer range) |
| Installation Environment | Indoor (offices, data centres | Outdoor (underground, long-distance networks) | OS2 (More versatile) |
| Cost | $0.20 – $0.50 per meter (cheaper) | $0.50 – $1.50 per meter (higher cost) | OS1 (More budget-friendly) |
| Ease of Installation | Easier to install indoors | Requires specialized installation for outdoor use | OS1 (Simpler setup) |
3) Final Verdict: Which One Should You Choose?
So, now you better understand the differences between OS1 and OS2 fibre cables, hopefully, you can make an informed decision. Thus, I must say that you can choose OS1 if your network is within the confines of a single building and requires a budget-friendly option. However, you can choose OS2 if the distance of your network is large (greater than 10 km). Moreover, if you require minimum attenuation and maximum productivity over a prolonged period of time. In short, both OS1 and OS2 are great options, but knowing these fundamentals will assist you in choosing the most suitable one! Apart from this, you can contact Dekam Fibres for getting high-quality reliable fibre optic cables designed for specific uses whether, indoor, outdoor, underwater or other.
