What is the difference between OS1 and OS2 Singlemode Optical Fibre?

Fibre optics has revolutionised data transmission, enabling high-speed and reliable communication over long distances. This technical article delves into the differences between OS1 and OS2 Singlemode fibre optics, including their core characteristics, performance specifications, and ideal applications. Understanding these differences will help network engineers and technicians make informed decisions when deploying fibre optic infrastructure. 

Fibre optics is the backbone of modern communication networks, facilitating rapid data transfer and offering immunity to electromagnetic interference. Singlemode fibre can be classified as OS1 or OS2 and is primarily designed to ensure efficient transmission of voice, data and images over long distances. This article aims to provide an in-depth comparison of OS1 and OS2 fibre optics to aid professionals in selecting the appropriate fibre type for specific network requirements.

OS1 fibre is designed for short-distance performance, making it suitable for short to medium-range transmissions (up to 2 km) in LAN (Local Area Network) environments. 

Applications include: LAN backbones, data centres, enterprise networks, and campus networks. 

OS2 fibre provides superior long-distance performance. It is designed for long-haul transmissions over extended distances (up to 40 km and beyond). 

Applications include: Metropolitan Area Networks (MANs), Wide Area Networks (WANs), long-distance connections between data centres, and outdoor installations. 

OS1 fibre offers a lower bandwidth compared to OS2, typically around 500 MHz·km at 1310 nm. It generally has higher chromatic dispersion, making it less suitable for high-bit-rate applications. 

OS2 fibre provides higher bandwidth, usually around 2000 MHz·km at 1310 nm, and exhibits lower dispersion, making it well-suited for high-speed data transmission applications over greater distances. 

Both OS1 and OS2 fibre cables share the same construction with a 250-micron coated optical fibre surrounded by aramid yarn strength members and an outer jacket for protection. Both OS1 and OS2 cables may have additional reinforcement to withstand harsh outdoor conditions. 

OS1 and OS2 fibre optics are compatible with standard single-mode connectors, such as SC, LC, and ST connectors, enabling seamless integration into existing network infrastructures. 

Selecting the right fibre optic type is crucial for optimising network performance. OS1 fibre optics excel in short-range applications including backbones, data centres, campus and inter-building applications, while OS2 fibre optics are better suited for long-haul applications. Understanding the differences outlined in this article will empower network professionals to make informed decisions when deploying fibre optic systems.