Trade.Information

Product Name: Alcatel-Lucent Branching Unit for Optical Fiber Submarine Cable System

Product Description

Flexible Submarine Optical Networking

The Alcatel Auto-latching Branching Unit (BU) is designed for
repeatered applications in submarine cable networks. It provides fiber branching
capabilities and a simple and robust scheme for reconfiguring the power feed
paths, enabling flexible and economical network solutions. BUs are key elements
in submarine networks where fibers need to be routed to more than a single
destination. Fiber-routing is a simple function but the BU also needs to provide
facilities for power-feeding. This is less simple because the BU needs to be
able to switch the power feed path to handle the possibility of cable breaks.

An Evolutionary Approach to Meet Operators’ Needs

Alcatel has supplied a number of BUs to different operators and
worked with them to understand their requirements and benefit from their
experience. This Alcatel BU is the latest step in the evolutionary process.
Early designs of BU switched to a particular configuration depending on the flow
of current between ports of the BU, thus requiring the operators to follow a
complex sequence of operations to ensure the correct current flows. To increase
stability one leg of the BU might include either current-holding or latching
relays. This latest Alcatel BU design provides full protection to all ports of
the BU and also simplifies and de-risks power switching. The BU configurations
(see diagrams on next page) allow current flow between any two legs of the BU,
with the other leg isolated and connected to a sea ground.

How to Switch Power

For switching the Alcatel BU offers two features:

> The BU will change configuration only when it is
close to zero volts.

This means that the energy dissipated by the switch is
negligible and the relay will not suffer any damage. A simple procedure of
adjusting a single PFE (Power Feeder Equipment) allows the operator to set this
condition before switching. If for any reason this isn’t achieved the BU will
not switch, thus avoiding the risk of an error.

> In all cases the configuration is held by latched
relays and is held under all conditions until an operator chooses
to change it.

As well as ensuring stability during a break or power dip, this
means that during re-configuration operators can focus on one BU at a time, with
the certainty that the other BUs will maintain their configuration.

Company Details

Formed from the merger of Alcatel and Lucent Technologies, Alcatel-Lucent combines two entities that share a common lineage that can be traced back to 1986, when Alcatel’s parent company, CGE (la Compagnie Générale d’Electricité), acquired... more