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Mark, There was an activity in ITU-T some time ago that looked at both max and min fibre loss as a function of wavelength. This led to the tables in Appendix I of G.695. http://www.itu.int/rec/T-REC-G.695-201501-I/en The wavelength range for 25GBASE-ER seems to be 1295 to 1310 nm. Within this range, the lowest loss will be at 1310 nm and the minimum loss value predicted by the work that was used for Appendix I of G.695 is 0.356 dB/km Regards, Pete Anslow |
Senior Standards Advisor From: Mark Kimber [mailto:MKimber@xxxxxxxxxxx]
Hi All, Thanks Matt for digging these up. Just to clarify, these presentations are for 20km links. The CW measurements made in these presentations agree quite well with the measurements I have made at 20km. (The Corning
presentation is with modulated data I think – I couldn’t see it explicitly stated.) The 25GBASE-ER is 40km and the additional fibre length allows for an increase interaction length which reduces the SBS threshold. The other point is that minimum fibre loss is not specifically considered in
these presentations. I am trying to see if I can get data on minimum fibre loss (dB/km) to see if my assumption of 0.25dB/km is valid. Just to confirm that for the ER spec, SBS might be a problem with an EML (not DML) Tx at 6dBm with low loss fibre. These conditions all happening together are fairly low probability but I think we should make
the spec robust. Thanks, Mark Kimber From: Matt Traverso (mattrave) [mailto:mattrave@xxxxxxxxx]
Hi All, In light of reviewing
kimber_3cc_01_1116 this morning, I did do a quick check on prior contributions – see
http://www.ieee802.org/3/av/public/2007_01/3av_0701_ten_1.pdf http://www.ieee802.org/3/av/public/2007_03/3av_0703_lingle_1.pdf --matt From: David Lewis [mailto:David.Lewis@xxxxxxxxxxxx]
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