New optical amplifier technology has been developed by Fujitsu and Fujitsu Laboratories for use in optical access systems that link subscribers to central offices. The technology has the ability to quadruple the splitting number and double the transmission distance.

The use of optical aggregation networks, in which optical signals between a central office and many subscribers are optically passed along, rather than converted into electrical signals, is proposed as one way to reduce the constantly growing amount of electrical power consumed by networking equipment.

Although passive optical networks (PONs), which increase transmission speeds in both downstream and upstream from the prevailing speed of 1Gbps to 10Gbps, are now starting to be deployed commercially, there are constraints in using them for optical aggregation networks.

This is because the number of optical network terminals (ONTs) for the most commonly used PON is typically limited to 32 connections and its transmission distance is also limited around 20km.

To address these constraints, especially in upstream bursts, the two companies have developed a burst-mode optical amplifier technology with a semiconductor optical amplifier (SOA), an integrated SOA-array module fabrication technology, and an SOA chip fabrication technology enabling uncooled operation to be achieved.

These three technologies, used together, make it possible to quadruple the splitting number in an optical access system and double the transmission distance between the central office equipment and the terminal equipment.