Re: [8023-10GEPON] On the downstream wavelength
Dear Frank,
Thank you for your important indication.
Actually, I have forgotten that as well.
So we can't help avoiding the use of wavelength below 1575nm for
10G-EPON downstream signals because of that kind of vague description as
shown in ITU-T G.984.5.
Best regards,
Ken-Ichi
At 2008/11/13 6:50 Frank Effenberger wrote:
> 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 USA
>
> 1700 Alma Drive, Plano TX 75075
>
> Cell (908) 670 3889
>
> Office/Home (732) 625 3001
>
>
>
--
Ken-Ichi Suzuki
NTT Access Network Service Systems Labs.
E-mail:kenyichi@xxxxxxxxxxxxxx
Tel:+81-43-211-3189/Fax:+81-43-211-8250