Motivation

The transmission capacity within each country and/or between countries has been rapidly growing due to the evolution of Internet services on a global scale. Optical fibre submarine cable systems at the heart of global networks are affected by such an increase in transmission capacity. In such a seamless global network, connectivity also becomes more important than ever for telecommunication carriers and providers. Optical fibre submarine cable systems include two types of system, repeatered systems and repeaterless systems. Repeaterless submarine cable systems are used for network extensions (e.g. for linking to islands just offshore) because of lower cost for installation and OAM. Repeatered systems are used for long haul large capacity transmission (e.g. for linking different continents through the oceans) by introducing line optical amplifiers.

This Question has responsibility for the following areas of standardization related to:

• Specifications of terminal equipment and optical fibre submarine cables in optical fibre repeatered submarine cable systems with various optical amplifiers such as Erbium Doped Fibre Amplifiers (EDFAs) and Raman amplifiers
• Specifications of terminal equipment and optical fibre submarine cables in optical fibre repeaterless submarine cable systems, including systems with remotely pumped optical amplifiers
• Specifications of test methods concerning the terminal equipment, optical fibre submarine cables and other equipment relevant to the submarine cable systems
• Specifications of forward error correction (FEC) for optical fibre submarine cable systems

NOTE: Marinised terrestrial cables (as defined in Recommendation G.972) are allocated to Q16/15

The following major Recommendations, in force at the time of approval of this Question, fall under its responsibility: G.971, G.972, G.973, G.974, G.975, G.975.1, G.976, G.977 and G.978.

Question

How should Recommendations G.971, G.972, G.973, G.975.1, G.976, G.977 and G.978 be amended from a viewpoint of cost effectiveness?

What new transmission techniques should be recommended to increase transmission capabilities of optical fibre submarine cable systems?

What new components and subsystems (fibre, component, etc.) should be utilized to improve system capacity and reliability?

What new test methods are necessary for the submarine cable systems?

What mechanical protection and system protection mechanisms should be recommended for high capacity submarine cable systems to improve systems reliability/availability?

What terrestrial and submarine integration should be recommended for the effective network systems?

What kind of optical submarine system should be standardized to support longitudinal/transversal compatibility?

What kind of optical fibre submarine cable is needed to support optical fibre submarine cable systems?

What enhancement can be made to existing published Recommendations to further reduce power consumption of optical fibre submarine cable systems?

What new Recommendations are necessary?

Study items to be considered include, but are not limited to:

• Transmission characteristics of optical fibre submarine cable systems
• Interface characteristics of optical fibre submarine cable systems
• Mechanical characteristics of the submarine portion of optical fibre submarine cable systems
• Test methods
• Evolution of submarine systems to higher bit-rates, including the effects of chromatic dispersion, polarization mode dispersion, and optical fibre nonlinearities
• Adoption of wavelength-division multiplexing/demultiplexing techniques
• Introduction of other types of fibre amplifiers, Raman amplifiers, distributed Raman amplifiers or semiconductor amplifiers operating at different wavelengths
• Flexibility for partial network upgrades
• Repeaters with optical amplifiers
• Use of branching devices in submarine networks
• New specifications for submarine systems in accordance with the objective of longitudinal / transversal compatibility
• Submarine systems with higher bit-rates of 40 Gbit/s or more, including the effects of chromatic dispersion, polarization mode dispersion, and optical fibre nonlinearities
• New dispersion accommodation techniques including dispersion management transmission lines and/or hybrid transmission lines for high speed optical fibre submarine cable systems
• Advanced FECs for high bit rate DWDM submarine systems
• New types of amplifiers operating at different wavelength bands
• Availability and reliability
• Engineering, Operations and maintenance
• Interface compatibility of submarine and terrestrial systems
• Terrestrial and submarine integrated networks
• Mechanical and systems level protection mechanisms
• System and cable repair procedures

Tasks

Tasks include, but are not limited to:

• Revisions to Recommendations G. 971, G. 972, G.973, G. 975.1, G. 976, G.977 and G.978 as required
• Update the text of G.Sup41, as required
• Update the data on cable ships and submersible equipment (as required)
• Develop additional Recommendations from progress on the above study items

NOTE: An up-to-date status of work under this Question is contained in the SG15 Work Programme at http://www.itu.int/ITU-T/workprog

Relationships

Recommendations:

• G.65x series, G.707, G.709, G.95x series, G.96x series.

Questions:

• Q5/15, Q6/15, Q7/15, Q.9/15, Q11/15, Q14/15, and Q16/15.

Standardization bodies, forums and consortia:

• IEC SC86A on fibre reliability and on underwater cables.