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Dear all, I am racking my brain to think how we can move forward on
this issue in a way that gives everybody at least 1 grain of rice in their bowl...
so how is this idea: I notice that in ITU G.984.5 (attached), which is the standard
that specifies the blocking filters for G-PON (and which is also relevant to 1G
EPON, by the way), the performance of the video blocking filter is specified in
Appendix II. This gives the shortest wavelength above the video band to
be “TBD (1574 or 1575nm)”. I happen to know that a very significant
deployment is using 1575nm as the video blocking filter cut-off wavelength for
their currently deploying PON systems. This is really the same kind of
practical limitation as the 1580nm cut-off of the OTDR filters, and I ask:
Shouldn’t we make the same allowances for this limitation as for the other? I
think that would be the right thing to do. My proposal: Refine the wavelength band for all downstream power budgets
to be 1575 to 1580nm. This makes the OLT 1nm tighter (which should not
really hurt us, because once you temperature control the transmitter, you
actually can control the wavelength quite tightly), and it makes the ONU filter
guard band 7% easier (every bit helps.) I will admit that this is a pretty small step. But at least
it is something, and shows our commitment to working to achieve commonality and
consideration of all interests. Sincerely, Dr. Frank J. Effenberger 弗兰克 埃芬博格 Huawei Technologies Cell (908) 670 3889 Office/Home (732) 625 3001 |
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T-REC-G.984.5-200709-P!!PDF-E.pdf
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