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Re: [802.3_100GNGOPTX] 802.3_100GNGOPTX Multi Path Interference experiments

Jonathan,

Do these eye’s have the same optical power levels? It looks like the one on the right is lower. If so then how do we know it isn’t just higher RJ due to lower SNR at the receiver (stemming from increased insertion losses in the misaligned connectors)?

 

Thanks,

Brian

 

From: Jonathan King [mailto:jonathan.king@xxxxxxxxxxx]
Sent: Tuesday, March 19, 2013 11:24 AM
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GNGOPTX] 802.3_100GNGOPTX Multi Path Interference experiments

 

 

Dear all,

Here’s a few snapshots (literally) of multi path interference in a simple single mode link. It was a quick experiment, with a well isolated instrument grade laser (impervious to reflections) so that just coherent multipath effects within the low loss link are captured.  It demonstrates:

•        Coherent Multi-path Interference penalty is real.

•        Near worst case penalties are observed in practice (despite a misleadingly reassuring low probability of occurrence).

•        Very slowly varying phenomena (minutes).

–       FEC can’t fix it.

–       EQ can’t fix it.

•        Need to budget for worst case.

 

 

Best wishes

jonathan