Single-mode fiber optic cables are primarily categorized as OS1, OS2, and ITU-T G-series fibers like G.652 and G.655, each optimized for specific distances, environments, and network applications.

OS1 and OS2 Fibers

• OS1: Designed for indoor applications, such as campus networks and building backbones. It features a tight-buffered construction with a small 9µm core, supporting distances up to 10 km at 10 Gbps. OS1 is cost-effective and flexible, suitable for office or enterprise networks where shorter runs are common .
• OS2: Optimized for outdoor and long-haul applications, including backhaul networks, FTTH, and WDM/DWDM systems. OS2 uses a loose-tube construction, allowing the fiber to flex without tension, and supports distances up to 200 km, with higher throughput capabilities (up to 100 Gbps). It is more durable and suitable for harsh environments .

ITU-T G-Series Single-Mode Fibers

• G.652 (Standard Single-Mode): The most common single-mode fiber, with a narrow core diameter (~9µm), designed for minimal signal loss and low attenuation. Ideal for long-haul and metropolitan networks, cable TV, and LANs. It efficiently transmits light over long distances and is compatible with most single-mode devices .
• G.655 (Non-Zero Dispersion-Shifted Fiber): Engineered to reduce dispersion at high speeds, supporting dense wavelength division multiplexing (DWDM). It is suitable for high-capacity, long-distance backbone networks, allowing multiple wavelengths to propagate with minimal signal degradation .
• G.651 and G.657: Less common variants; G.651 is used in backbone networks requiring high precision, while G.657 is optimized for bend-insensitive applications, making it ideal for FTTH and indoor installations with tight bends .

Key Characteristics of Single-Mode Fibers

• Core Diameter: Typically 8–10µm, allowing only one light mode to propagate, reducing modal dispersion and attenuation .
• Wavelengths: Commonly operate at 1310 nm and 1550 nm, suitable for long-distance, high-speed transmission .
• Applications: Long-haul telecom, metro networks, data centers, FTTH, and high-speed enterprise networks .
• Advantages: Supports longer distances and higher bandwidth than multimode fibers, with minimal signal loss and modal dispersion . Understanding these types helps in selecting the right fiber for your network, balancing distance, speed, environment, and cost. OS1 is ideal for indoor, short-range deployments, OS2 for outdoor long-haul, and G-series fibers provide specialized performance for high-speed or DWDM applications.