Fujitsu Develops Optical Amplifier Technology for Next Generation Optical Access Systems

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, has been proposed as one way to reduce the constantly growing amount of electrical power consumed by networking equipments. Although passive optical networks (PONs), which increase transmission speeds in both downstream and upstream from the prevailing speed of 1Gb/s to 10Gb/s, are now starting to be deployed commercially, there are constraints in using them for optical aggregation networks 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, Fujitsu and Fujitsu Laboratories 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. 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.

This makes it possible for a next-gen optical access system to be used as an optical aggregation network at low cost and with low power consumption requirements, paving the way for cloud infrastructure. The research results achieved by the Commissioned Research of National Institute of Information and Communications Technology (NICT) have been applied to portion of this work.

Details of these technologies were presented at the 37th European Conference and Exhibition on Optical Communication Conference (ECOC2011), held in Geneva, Switzerland from September 18 to 22.