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Re: [802.3_25GSMF] Meeting starting now in Travis A/B 3rd floor



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
43-51 Worship Street | London, EC2A 2DX, UK
Direct +44 2070 125535
|

 

From: Mark Kimber [mailto:MKimber@xxxxxxxxxxx]
Sent: 11 November 2016 15:17
To: STDS-802-3-25GSMF@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_25GSMF] Meeting starting now in Travis A/B 3rd floor

 

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]
Sent: 09 November 2016 17:15
To: STDS-802-3-25GSMF@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_25GSMF] Meeting starting now in Travis A/B 3rd floor

 

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]
Sent: Wednesday, November 09, 2016 7:09 AM
To: STDS-802-3-25GSMF@xxxxxxxxxxxxxxxxx
Subject: [802.3_25GSMF] Meeting starting now in Travis A/B 3rd floor