ITU Home Page International Telecommunication Union Franšais  Espa˝ol 
Print Version 
ITU Home Page
Home : ITU-T Home : Study Period 2001-2004
Question 17/15 - Characteristics of optical components and subsystems

(Continuation of Questions 17 and 19/15)

Background and justification

The increasing complexity of optical networks has brought about an increasing diversity of active and passive optical components and devices. These components and devices find applications in local access networks, interoffice and long distance networks, and in submarine networks. Functions differ with the application, whether uni-directional or bi-directional, point-to-point or point-to-multipoint, single or multiple wavelengths, with or without optical amplification.

The responsibility under this Question includes the following Recommendations:

G.661: Definition and test methods for the relevant generic parameters of optical amplifiers

G.662: Generic characteristics of optical amplifier devices and sub-systems

G.663: Application-related aspects of optical amplifier devices and sub-systems

G.671: Transmission characteristics of optical components and subsystems


  • What components aspects and characteristics need to be specified to support local access networks, interoffice and long distance networks, and submarine networks including evolution to OTN?
  • What enhancements should be made to existing draft or published Recommendations to reflect technological developments?

Study items

Study items to be considered include:

  • Active devices and sub-systems such as optical fibre amplifiers (OFAs), including parameter definitions and measurement (IEC test methods), classification of devices and sub-systems, optical nonlinearities, polarisation, dispersion, noise and optical surge
  • Passive components such as splices and connectors, attenuators and terminators, 1-by-N branching components (such as splitters and combiners), 2-wavelength optical multiplexers and demultiplexers, filters and isolators, optical switches, dispersion compensators, optical mux/demux
  • Worst-case transmission parameter values (for all environments and to end-of-life) for passive components in digital applications
  • Specification of optical amplifier characteristics in multichannel applications including their frequency equalization and dynamic response
  • Semiconductor optical amplifiers
  • Specification of optical components and sub-systems for optical networking including optical add/drop multiplexers and optical cross connects. (Optical subsystems in this context relate to the optical aspects of the network elements)
  • Specification of optical components and sub-systems for local access networks
  • Specification of other optical amplifier sub-systems (e.g. those resulting from integration of optical amplification with optical multiplexing or dispersion compensation)
  • Specification of components for present and future optical networks, such as switch-resistant OAs, gain-flattened OAs and wideband OAs, optical circulators, optical modulators, electrically controlled optical attenuators, passive and active dispersion compensators including PMD compensators, multi-wavelength and/or fine tuning lasers & ext. modulators, high-power lasers for Raman amplification "flat-top" passband filters, small-size switching matrixes, wavelength/frequency transponders or converters, optical repeaters (2R, 3R)
  • Components and subsystems for use in soliton transmission;
  • Possible extension of OFAs, components and subsystems for use in bi-directional transmission systems on a single fibre
  • OFAs other than EDFAs
  • Operations, administration, and maintenance (OA&M) aspects of OAs
  • Further quantification of optical nonlinearities
  • Parameter values for components with respect to statistical values, such as mean and standard deviation, short-term variations with environment, long-term degradation with aging, use of these in system calculations
  • Safety and reliability aspects of all the above components
  • Possible extension of the components and subsystems for use in optical networks that are optimized for packet data transport, e.g. IP or ATM over WDM, including optical label switching components

Specific tasks and deadlines

  • Revise Recommendations G.661, G.662, G.663 (2004) and G.671 (2003).
  • Prepare new Recommendations as required


  • ITU-T SG 13 on IP related issues
  • ITU-T SG 6 on physical aspects of outside plant for optical amplifiers and for active and passive optical components
  • IEC TC86 and its sub committees on optical passive components, on dispersion compensator specifications and on optical fibre amplifiers, and on semiconductor optical amplifiers


Top - Feedback - Contact Us - Copyright ę ITU 2004 All Rights Reserved
Contact for this page : TSB EDH
Updated : 2004-10-21