G652

G.652 is an ITU-T recommendation that defines the characteristics of standard single-mode optical fiber and related cables used in telecommunications. It specifies a silica-core, single-mode, step‑index fiber designed for low loss and reliable transmission in the conventional telecommunications windows around 1300 and 1550 nanometers. The standard outlines typical physical properties, such as a core of about 9 micrometers and a cladding of about 125 micrometers, along with general mechanical and environmental requirements and testing methods for attenuation and dispersion.

A key aspect of G.652 is its guidance on optical performance across the commonly used wavelength bands. It identifies the zero-dispersion region near 1310 nm to minimize dispersion, while ensuring acceptable attenuation in the 1310 and 1550 nm windows. The standard also discusses variations among fiber types, known as subfamilies, including G.652.A, B, C, and D, which differ in properties such as attenuation, dispersion, and hydroxyl (OH) content. In particular, later revisions introduced low water peak fibers (notably G.652.C and G.652.D) that reduce attenuation near 1383 nm, enabling additional wavelength channels and improved compatibility with dense wavelength-division multiplexing.

G.652 fibers form the baseline for much of modern telecom infrastructure, supporting long-haul, regional, and metropolitan networks. Contemporary variants such as G.652.E or G.652.D emphasize improved bend tolerance and compatibility with evolving multiplexing techniques, while still conforming to the core characteristics defined by the standard. The specification also covers handling, installation, and durability considerations relevant to field deployment.