[LINK] Optical broadband research

[stephen at melbpc.org.au]

Researchers increase speed and coverage of passive optical broadband 
connections .. 

By John Blau, IDG News Service February 20, 2007
<http://www.infoworld.com/article/07/02/20/HNsiemenshomefiberlink_1.html>

 Researchers from Siemens have successfully tested technology that not 
only increases the speed of passive optical broadband connections to the 
home or office but also the radius of coverage. 

The team of researchers, sponsored by the European Union, achieved 
downstream transmission rate of 10Gbps and upstream speed of 2.5Gbps over 
a passive optical access network, Siemens said Monday. 

By comparison, current gigabit passive optical network (GPON) technology 
supports downstream data rates of 2.5G bps and upstream rates of 1.2G 
bps. 

In addition, the researchers were able to extend the distance between the 
hub and subscribers, the equivalent of the "local loop" in copper 
networks, from 20 kilometers to 100 kilometers. The number of subscriber 
lines per splitter, where the optical signal is divided up to serve more 
destinations, was also expanded from 64 to 512. 

Numerous operators are keen to deploy high-speed broadband access systems 
that offer far greater speed than DSL (Digital Subscriber Line) 
technology, which uses existing copper twisted pairs to provide data 
rates of up to 50Mbps, Siemens said. Services such as VOD (video-on-
demand) and HDTV (high-definition TV) perform best when delivered over 
fiber-optic subscriber lines. 

At the same time, new GPON systems eliminate the need for aggregation 
devices commonly used to collect and distribute data traffic locally. In 
the future, operators will be able to connect subscribers directly to the 
core network, Siemens said. 

Earlier this year, Siemens researchers achieved a transmission speed of 
107Gbps over a single optical fiber.

The speed, which the company claims sets a record for electrical 
processing of data through a fiber-optic cable, was reached over a 100-
mile route. 

Siemens has developed a new transmission and receiving system that is 
able to process data directly before and after its conversion into 
optical signals using electrical processing only. Current systems 
handling very high data rates have to split signals into multiple lower 
data-rate signals and later reconvert them from optical to electrical, a 
process that adds to costs and reduces network capacity. 
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Cheers all ..
Stephen Loosley
Victoria, Australia