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Plastic optical fibre eyes data centre applications

15 June 2011
German firm VI Systems says its 850nm vertical cavity surface emitting laser (VCSEL) is behind the breakthrough experiment by scientists from Georgia Institute of Technology, who transmitted 25Gbps over 100m of 80µm-diameter-core plastic optical fibre (POF). POF is usually limited to lower speeds between 50Mbps and 1Gbps in automotive and home networks.
The experiment, originally reported at the Optical Fibre Conference (OFC) in Los Angeles earlier this year,  was the first time such a high data rate over POF had been demonstrated using a conventional 850nm VCSEL, according to George Schaefer, VI Systems’ director of sales.  Such a high-speed single VCSEL offers the bit rates normally associated with more expensive DFB lasers.
Higher aggregate speeds can be attained by using the high-speed VCSEL in an array – 1x4 and 1x12 chip arrays are available from VI Systems.  This level of performance opens up potential new markets for POF in data centre interconnection, including active optical cables at 40 and 100 Gbps, Fibre Channel at 14 Gbps and 28 Gbps, and Infiniband FDR (14 Gbps) and EDR (26 Gbps) applications.
As well as being low cost, POF-based systems are highly forgiving of alignment errors, which relaxes the manufacturing requirements. In the Georgia Tech experiment, the coupling tolerances to reach error-free transmission – defined as a bit error ratio <10-12 – were as large as ~35µm.
By Pauline Rigby