Generation Ethernet. There was a call for interest in July for Next Generation Ethernet which will be 4 lanes of 25G. We were able to design a fibre for the specific VCSEL that we had, to optimise the dispersion compensation, and we were able to go 150m at a much higher data rate of 25Gbps as opposed to 10Gbps. I think this is a very important development which will open up the doors for next generation OM3 and OM4 multimode fibre, which is being discussed by standards bodies now.
NE: Why has this only been done now?
RP: Multimode fibre has slowly but continuously been improving over the years. The primary metric that people
have always been working on was modal dispersion. There was an assumption that chromatic dispersion was not as important as modal dispersion, and as people started increasing bandwidth further and further, and VCSELs and data rates started going faster and faster, no one took the time to look back and say, ‘Are our previous assumptions still correct?’ And in fact they weren’t. Eventually we reached a point where the transceivers had an issue. The spectral width of these VCSELs was sufficiently broad that chromatic dispersion became a significant part of total signal distortion. But people carried on all going down one path, improving one metric and neglecting the second. There is a calculation in the standard
for including chromatic dispersion but the problem is it is not included in the same way. It assumes that all the wavelengths get launched into all the modes equally, which is in fact not the case. There was a modal-chromatic interaction that was not recognised until now. We discovered the problem in
January 2004 and in June 2009 we finally made the connection. We hadn’t previously been able to do that because we didn’t have the right testing equipment so we built a differential mode delay measurement system, using a titanium-sapphire laser which gave us the resolution we needed. When we started looking at the modal dispersion of the fibre and calculated
Specialists in Data Centre Fire & Security Systems
When it come to the protection of your most important mission critical equipment and assets, TFS can assist in the design, installation and maintenance of Fire Detection, Fire Suppression, CCTV, and Water Detection Systems.
TFS can provide a complete package, including offsite monitoring, 24 hours a day 365 days a year call out, and third party accreditation. When it comes to choosing the right supplier, ensure you come to the professionals with many years experience.
“It would be so easy just to pick up the orders and then meet those demands in a professional manner, but the fact that TFS is eager to challenge what other companies would accept as ‘the simple answer’ by finding more cost and operationally effective solutions is one of the reasons why, in my view, TFS sets itself aside from other companies within the security arena.”
Director of Security & Major Investigations Co-operative Financial Services Ltd.
tailored fire & security
www.tfs-ltd.com sales@tfs-ltd.com
www.netcommseurope.com NETCOMMS europe Volume I, Issue 6 2011 13
tailored fire & security
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52