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Telecom Fibers

Definition: optical fibers for use in optical fiber communications

Alternative term: telecommunication fibers

German: Telekom-Fasern

Categories: article belongs to category fiber optics and waveguides fiber optics and waveguides, article belongs to category lightwave communications lightwave communications


Cite the article using its DOI: https://doi.org/10.61835/iwz

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Telecom fibers are optical fibers which are used in optical fiber communications. This is a huge application field for fibers; several hundred millions of kilometers of telecom fibers are currently fabricated per year.

Mainly the following types of telecom fibers are used:

A standard single-mode telecom fiber for the 1.3- or 1.5-μm wavelength region is the SMF-28 of Corning, and there is the enhanced version SMF-28e. The mode field diameter is ≈ 9.2 μm at 1310 nm (effective mode area = 67 μm2), or 10.4 μm at 1550 nm (85 μm2). The single-mode cut-off is at 1260 nm. The Lucent AllWave and the Alcatel ColorLock fibers have quite similar properties.

Other telecom fibers have somewhat modified properties, making them more suitable in certain areas:

  • Corning offers Vascade fibers in different versions, e.g. the Vascade L1000 with an increased effective mode area, the non-zero dispersion-shifted Vascade LS+, and the Vascade LEAF fiber, a dispersion-shifted fiber with increased mode area.
  • Lucent offers different versions of their TrueWave fiber, e.g. the TrueWave-RS with reduced dispersion slope and the TrueWave-XL with larger mode area.
  • Alcatel developed the TeraLight fiber, another non-zero dispersion-shifted fiber. (Alcatel has later merged with Lucent to form the company Alcatel-Lucent.)

As glass fibers are not sufficient robust for directly laying them down in a building or even in the ground, they are incorporated into optical fiber cables, where various polymer layers and sometimes even metallic armors provide additional protection. For flexible indoor use, fiber patch cables with standardized fiber connectors are suitable.

Standards for Telecom Fibers

The International Telecommunications Union (ITU) has developed a number of standards for various types of fibers as used for optical fiber communications. Some of the most important of those standards are listed in Table 1.

G.650.1 (06/04)Definitions and test methods for linear, deterministic attributes of single-mode fibre and cable
G.651 (02/98)Characteristics of a 50/125 μm multimode graded index optical fibre cable
G.651.1 (07/07)Characteristics of a 50/125 μm multimode graded index optical fibre cable for the optical access network (pre-published)
G.652 (06/05)Characteristics of a single-mode optical fibre and cable
G.653 (12/06)Characteristics of a dispersion-shifted single-mode optical fibre and cable
G.654 (12/06)Characteristics of a cut-off shifted single-mode optical fibre and cable
G.655 (03/06)Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable
G.656 (12/06)Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport
G.657 (12/06)Characteristics of a bending loss insensitive single mode optical fibre and for the access network

Table 1: Important ITU standards concerning telecom fibers.

There are various other standards for telecom fibers, e.g. from ISO and IEC.

Relevant Properties of Telecom Fibers

Many different properties of a telecom fiber can be relevant for the achievable performance (partly depending on details of the used fiber-optic links) or concerning other aspects of use:

case study fiber dispersion engineering

Case Studies

Case Study: Dispersion Engineering for Telecom Fibers

We explore different ways of optimizing refractive index profile for specific chromatic dispersion properties of telecom fibers, resulting in dispersion-shifted or dispersion-flattened fibers. This also involves automatic optimizations.

case study parabolic index fiber

Case Studies

Case Study: Telecom Fiber With Parabolic Index Profile

We investigate how intermodal dispersion of a multimode fiber can be minimized with a parabolic doping profile.

  • The strength of nonlinear effects in the fiber is mainly determined by the effective mode area, which can differ quite substantially between different telecom fibers, and less by the chemical composition of the fiber core. It is often an important parameter in a system design.
  • For some applications, the sensitivity to bend losses is important. This is particularly the case for indoor installations, it may be impractical to avoid tight bending. A manufacturer may e.g. specify the induced macrobend loss in some wavelength range for a few turns of fiber wound up on a mandrel with given bend radius of e.g. 15 mm.
  • The core–clad concentricity can be important for the possible quality (in terms of transmission losses) of fusion splices.
  • Details of the protective fiber coating, such as its outer diameter and chemical composition, can also be relevant in various ways, e.g. when mounting fiber connectors or concerning temperature resistance.
  • There can be various environmental specifications, e.g. concerning the allowed temperature range, allowed tensile stress and increased transmission losses caused by high temperatures or water immersion.
  • The available fiber length per spool (often many kilometers) may be limited. However, telecom fibers are mostly drawn from large preforms, each one delivering many kilometers of fiber.

More to Learn

Case studies:

Encyclopedia articles:


[1]W. A. Gambling, “The rise and rise of optical fibers”, J. Sel. Top. Quantum Electron. 6 (6), 1084 (2000); https://doi.org/10.1109/2944.902157
[2]Standards of the International Telecommunication Union (ITU), see http://www.itu.int/

(Suggest additional literature!)

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