The Southern Cross network was designed, manufactured and constructed under a contract awarded in October 1998 to a consortium formed by Alcatel and Fujitsu.
The network is a fourth generation optical fibre amplified submarine cable system. In constructing the Southern Cross cable, Alcatel has utilised Synchronous Digital Hierarchy (SDH) and Dense Wave Division Multiplexing (DWDM) to create a triple-ring network capable of operating at 10 Gbps x 16 wavelengths per fibre pair.
 |
|
Diagram sourced from Alcatel
|
SDH is a family of fibre-optic transmission rates from 155.52 Mbit/s to 10 Gbps. SDH delivers the flexibility to transport many different signals with different capacities.
WDM is a method of increasing the traffic capacity of optical fibres by simultaneously operating at more than one wavelength (colour). Signals are multiplexed by transmitting different wavelengths down the same fibre.
Alcatel manufactured all of the cable, landing station equipment and some of the repeaters at its plants in Australia, England, France, Germany, Italy and the United States. Fujitsu also manufactured repeaters, at its Japanese facility.
The cable is based on optical fibres set in a steel tube filled with a special jelly to protect the fibres from water penetration into the cable and from hydrogen. This is protected by high-strength steel wires and surrounded by seam-welded copper to form the composite conductor. This is then insulated with high-density polyethylene - which also provides abrasion resistance - to form lightweight cable (17mm in diameter).
|
|
|
A repeater being prepared for loading
|
Additional layers of galvanised steel wires are added where necessary to create armoured cable to provide additional protection to the cable on the ocean floor in shallower water sections. Southern Cross includes 2,485km of armoured cable, and the cable is also buried in the ocean floor, where it is installed in water depths of less than 2km wherever feasible. This includes mid-ocean rises between Australia and New Zealand and between Australia and Fiji.
At intervals of between 40 and 70km (depending upon the length and capacity of each segment) the optical signals are amplified by repeaters (optical amplifiers). Power for the underwater amplifiers is provided by a DC current of 1.0A delivered from Power Feed Equipment at the terminal stations at up to 10,000V DC potential.
|
