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Question 15/15 - Characteristics and test methods of optical fibres and cables

(Continuation of Question 15/15)

Background and justification

Optical fibre cables are being deployed at accelerated rates in telecommunication networks worldwide. These fibres find wide application in local access networks, interoffice and long distance networks, and in submarine networks.

The responsibility under this Question includes the following areas of standardization:

  • The description and testing of basic single-mode and multimode fibre types, with parameter tables describing the variations within each of the basic types
  • Definitions of parameters and associated test methods for geometrical, transmission, and mechanical reliability characteristics

The responsibility under this Question includes the following Recommendations:

G.650: Definition and test methods for the relevant parameters of single-mode fibres

G.651: Characteristics of a 50/125 um multimode graded-index optical fibre cable

G.652: Characteristics of a single-mode optical fibre cable

G.653: Characteristics of a dispersion-shifted single-mode optical fibre cable

G.654: Characteristics of a cut-off shifted single-mode optical fibre cable

G.655: Characteristics of a non-zero dispersion-shifted single-mode optical fibre cable


  • What fibre characteristics are needed to support bit-rates up to and above 40 Gbit/s with time-division multiplexing (TDM)?
  • What fiber characteristics are needed to support systems that mix both analogue and digital modulation formats?
  • What fibre characteristics are needed to open new spectral transmission regions as the passband of optical amplifiers increases and as the number of wavelength-division multiplexed channels increases?
  • What specific fibre characteristics are needed to support systems in the metropolitan networks?
  • What specific fibre characteristics are needed to support CWDM applications?
  • How can the nonlinear optical effects that accompany reduced channel spacing be characterized and controlled?

Study items

Geometrical, mechanical, and optical properties of the glass and coating, for single-fibre applications

  • Reliability (lifetime and failure rate) under a wide variety of temperature and humidity environments; long-term aging
  • Completion of the definition, modelling, and measurements of Polarization Mode Dispersion (PMD), relationship between fibre and cable values, interaction with chromatic dispersion
  • Determine how the attenuation, chromatic dispersion, and bending loss of fibres affects their use in various applications around 1600 nm
  • Test methods for nonlinear parameters (describing SBS, SPM, four-wave mixing, modulation instability, soliton formation, etc.) such as power thresholds, effective area, nonlinear coefficients
  • Possible additional fibre types, and additional parameter tables within the existing Recommendations
  • Possible additional fibre types optimized for the metropolitan networks
  • Length uniformity of fibre geometrical and transmission characteristics that have a functional impact on systems, and are not merely a quality control issue

Specific tasks and deadlines

Modify parameters in G.651, G.652, G.653, G.654, and G.655; (within 2002)

  • Develop new Recommendations or parameter tables within existing Recommendations for possible additional fibre types; (within 2002)
  • Develop definitions of new parameters, and corresponding factory and field test methods, RTMs and ATMs, for G.650: (within 2002)


Other relevant Questions of SG 15 on optical systems

  • ITU-T SG 6 on cable issues and monitoring the integrity of installations
  • IEC SC86A on general fibre matters, especially reliability, cable performance, and fibre test calibration


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Updated : 2004-10-21