MPP (Microwave Photonics Products), which is an industry information publication on microwave and photonics products aiming at the fusion of optic fiber communications technology and mobile communications technology, published a special contributed article about 10 Gbps active optical access system.
This 10Gbps active optical access system was researched and developed by Hitachi Ltd. and Keio Univ. The purpose is to popularize a high-speed access network throughout all over the world, and to resolve regional differences such as digital divide issues.
PON (Passive Optical Network), which is widely prevalent for an access network today, system has limitations of the maximum number of ONUs (Optical Network Units) and the maximum transmission distance between OLT (Optical Line Terminal) and ONUs. This is because the more ONUs increases, the weaker the optical power due to dividing optical power (broadcast) at a splitter.
We proposed a scalable active optical access network architecture using high-speed optical switches, which increases four times the number of subscribers per OLT as well as double the distance between OLT and ONUs. To support 10 Gbps required by high-speed optical access system, 10 nsec high-speed PLZT optical switch was developed. This PLZT switch achieved six-digit high-speed switching time compared to the conventional optical switches.
This work was a part of the R&D on photonic network promoted by Ministry of Internal Affairs and Communications, and supported by National Institute of Information and Communications Technology.