Single-mode fiber optic cable specifications

Single-mode fiber optic cables typically feature a 9 µm core, operate at 1310 nm and 1550 nm wavelengths, and support long-distance, low-attenuation transmission with minimal dispersion.

Core and Cladding

Single-mode fibers have a core diameter of approximately 8–10 µm, surrounded by a 125 µm cladding made of silica glass, often germania-doped for refractive index control . The small core allows light to propagate in a single mode, minimizing modal dispersion and enabling long-distance transmission up to 100 km without signal regeneration . Core concentricity error and cladding non-circularity are tightly controlled to ensure consistent optical performance .

Wavelength and Transmission

Single-mode fibers are designed for operation primarily in the 1310 nm (O-band) and 1550 nm (C-band) regions, with some fibers supporting the L-band (1565–1625 nm) for DWDM systems . They exhibit low attenuation, typically around 0.35 dB/km at 1310 nm and 0.22 dB/km at 1550 nm, and maintain low chromatic dispersion, which is critical for high-speed data transmission .

Standards and Types

The most widely used standard is ITU-T G.652, with variants such as G.652.D offering full-spectrum capability and compatibility with GPON, 5G fronthaul, and DWDM systems . Fibers also comply with IEC 60793-2-50, TIA/EIA 492-CAAB, and Telcordia GR-20-CORE standards . OS1 and OS2 classifications define performance for indoor and outdoor installations, respectively, with OS2 optimized for long-haul and high-bandwidth applications .

Mechanical and Environmental Properties

Single-mode fibers are coated with dual-layer acrylate or proprietary coatings to enhance durability, reliability, and identification . They are proof-tested at ≥100 kpsi to ensure mechanical strength and resistance to microbending. Fibers are suitable for various cable constructions, including loose tube, tight-buffered, ribbon, and central tube designs, and can withstand harsh environmental conditions, including direct burial and aerial deployment .

Key Performance Parameters

• Mode Field Diameter (MFD): ~8–10 µm
• Cut-off Wavelength: <1260 nm for single-mode operation
• Attenuation: 0.22–0.35 dB/km depending on wavelength
• Chromatic Dispersion: 17 ps/nm·km at 1550 nm for G.652.D
• Polarization Mode Dispersion (PMD): Typically <0.1 ps/√km
• Macrobending Loss: Specified per ITU-T G.657 for bend-insensitive fibers

Applications

Single-mode fibers are ideal for telecom backbones, data center interconnects, FTTH deployments, long-haul, metropolitan, and access networks. Their low-loss, high-bandwidth characteristics make them suitable for analog and digital transmission, including high-speed Ethernet, GPON, and DWDM systems . By selecting the appropriate fiber type, coating, and cable construction, network designers can optimize performance, reliability, and longevity for both indoor and outdoor deployments.