Date post: | 30-May-2018 |
Category: |
Documents |
Upload: | munitech4u |
View: | 222 times |
Download: | 0 times |
of 16
8/9/2019 Fiber Optic Seminar (optical submarine cables)
1/16
Optical submarine
telecommunication cables
By : Munish Bansal
Roll No.- 06429
8/9/2019 Fiber Optic Seminar (optical submarine cables)
2/16
Contents A brief history
What and where are submarine cables
Laying and maintenance Cables and the environment
Effects of human activities
The future
8/9/2019 Fiber Optic Seminar (optical submarine cables)
3/16
Abrief history-1
1840-1850: telegraph cables laid in rivers & harbours; limited
life, improved with use of gutta percha insulation.
1850-1: 1st international telegraph link, England-France, later
cables joined otherEuropean countries & USA with Canada
1884: First underwater telephone cable service from SanFrancisco to Oakland
8/9/2019 Fiber Optic Seminar (optical submarine cables)
4/16
Abrief history-2
1956: Invention of repeaters (1940s) & their use in TAT-1,the 1sttrans-Atlantic telephone cable, began era of rapidreliable communications
1986: First international fibre-optic cable joins Belgium &UK
1988: First trans-oceanic fibre-optic system (TAT-8)begins service in the Atlantic
8/9/2019 Fiber Optic Seminar (optical submarine cables)
5/16
What and where are submarine
cables?
Early telegraph cable
8/9/2019 Fiber Optic Seminar (optical submarine cables)
6/16
Modern submarine cables
8/9/2019 Fiber Optic Seminar (optical submarine cables)
7/16
How submarine cables work?
Modern submarine telecommunications cables rely on aproperty of pure glass fibres, whereby light is transmitted byinternal reflection
Because the light signal loses strength en route, repeaters areinstalled along the cable to boost the signal
New systems rely on optical amplifiers glass strandscontaining the element, erbium. Strands are spliced atintervals along a cable & then energized by lasers that causeerbium-doped fibresto lase& boost optical signals
8/9/2019 Fiber Optic Seminar (optical submarine cables)
8/16
Atypical submarine cable system
8/9/2019 Fiber Optic Seminar (optical submarine cables)
9/16
Cable size
Cables are small; deep-ocean typeswithout protective armour are typically17-20 mm diameter, similar to that of a
garden hose or beer bottle cap Armoured fibre-optic cables may reach50 mm diameter
In contrast, submarine oil/gas pipes reach900 mm diameter, & fishing trawlstypically range over 5,000 50,000 mmwidth
Cable lengths vary; one of the longest isthe SEA-ME-WE 4 system at ~20,000km
8/9/2019 Fiber Optic Seminar (optical submarine cables)
10/16
Laying and maintenance
Laying involves:-
Selection of route
Assessment of potential impacts of cable laying on
environment
Full survey of route and its final selection Design cables to meet environmental conditions
Laying of cables
8/9/2019 Fiber Optic Seminar (optical submarine cables)
11/16
Cable laying
Purpose built ships accurately place cables on or under the
seabed, guided by the route survey
Shallow water laying may be aided by divers; deep water
laying may involve remotely operated vehicles
8/9/2019 Fiber Optic Seminar (optical submarine cables)
12/16
Cables and the environment
Professionally installed fiber-optic cables have a neutral to
benign effect on the marine environment
Their small diameter means that their footprint is small,
especially when compared to submarine pipelines
They are composed of non-toxic materials that are stable insea water
8/9/2019 Fiber Optic Seminar (optical submarine cables)
13/16
Effects of human activities
Submarine cables come into increasing contact with other
seabed users especially fishing & shipping industries
~70% of all cable faults are from fishing & anchoring Natural hazards, including current abrasion & earthquakes,
cause ~12% of faults
Most faults occur in water depths less than 200 m & result
mainly from human activities Faults in water deeper than 1000 m result mainly from
natural causes
8/9/2019 Fiber Optic Seminar (optical submarine cables)
14/16
Submarine cables and the futureTechnology:
Cable design & operations are constantly evolving. Future
systems are expected to have even greater capacity andreliability
Development of ocean observatories will rely on new cable
technology including attached environmental sensors &
docking modules for submarine survey vehicles todownload data & recharge
Cables, with sensors to detect chemical & physical changes,
are planned for maritime & coastal defenses
8/9/2019 Fiber Optic Seminar (optical submarine cables)
15/16
Environment: Cable systems in some regions are likely face more natural
hazards related to changing climate
Climate change may also affect other marine activitiessuch as fishing, with potential impacts on cables
Measures to preserve biodiversity, ecosystems & resourcesvia various protection zones in national waters & highseas, may impinge upon cable passage
The ocean, especially coastal seas, will be subject toincreased human activities such as expansion of renewableenergy schemes
8/9/2019 Fiber Optic Seminar (optical submarine cables)
16/16
Thank You