Re: [8023-10GEPON] Downstream wavelength for 10G EPON
Dear Ken-Ichi,
Yes, your summary is good, and thanks for labeling the option D.
Regards,
Frank E.
-----Original Message-----
From: Ken-Ichi Suzuki [mailto:kenyichi@ansl.ntt.co.jp]
Sent: Thursday, August 09, 2007 3:31 AM
To: STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON] Downstream wavelength for 10G EPON
Dear Frank,
Thank you for providing your newly proposed wavelength plans.
I am Ken-Ichi Suzuki of NTT and I have comments as below.
In option C, in order to receive signals in both narrow (1574-1580 nm)
and wide (1580-1600 nm) band range, I think that the lower limits of an
optical filter pass-band must be 1574 nm.
If it is true, I think option C (called option D?) should be defined as
1574 ~ 1600 nm.
Considering the coexistence with RF video and the use of common optical
filter for each class, I think I can conclude option B and D are
acceptable for me.
These and the attached file are for my understanding.
Option A: 1560 ~ 1580 nm
Option A can receive signals in both narrow and wide wavelength ranges.
The central wavelength for PX10/20 is 1570 nm near one of CWDM grids.
Option A does not allow 10GEPON to coexist with RF video because of 0
guard band.
Option B: 1574 ~ 1594 nm
Option B can receive signals in both ranges.
The central wavelength is 1584 nm (near the anti-CWDM grid).
Option B allows 10GEPON to coexist with RF video with the guard band of
14 nm.
Option C: 1580 ~ 1600 nm
Option C can not receive signals in both ranges thus forcing us to
develop dedicated optical filters for each class.
The central wavelength is 1590 nm near one of CWDM grids.
Option C allows 10GEPON to coexist with RF video with the relatively
wider guard band of 20 nm.
Option D: 1574 ~ 1600 nm
Option D can receive signals in both ranges.
The central wavelength for PX10/20 can be selected at 1590 nm near one
of CWDM grids.
Option C allows 10GEPON to coexist with RF video with the guard band of
14 nm.
Best regards,
Ken-Ichi
At 2007/08/09 10:05 Frank Effenberger wrote:
> Dear All,
>
>
>
> I agreed at the last meeting to facilitate the development of a more
> inclusive wavelength plan for the downstream.
>
>
>
> The current situation is that the PX30 budget would seem to require cooled
> transmitters, and so the 6nm wide transmitter window centered at 1577nm is
> not an extra burden.
>
>
>
> However, for the PX10 and PX20 budgets, the OLT transmitter may be an
> uncooled type, both because the output power is low, and because in the
case
> of PX10, the fiber distance is shorter and so dispersion control is less
> needed. Therefore, there seems to be a justification for making the
> wavelength band for the PX10 and PX20 types wider.
>
>
>
> So, the question then becomes: how to make the window wider? It was
> discussed at the meeting that the wider window should contain the narrow
> window inside of it. This has the possibility of defining a universal ONT
> that can receive both the wide and narrow OLT signal. How that actually
> works out in practice will have to be seen.
>
>
>
> One aspect to consider is the re-use of industry standard wavelength
plans,
> since then components are already available. From this perspective, the
> CWDM wavelength at 1571 leaps out as a potential band. It is true that
the
> CWDM band is actually from 1563 to 1577 nm, but that is meant for 0~70 C
> operation, and expansion to a 20nm width naturally occurs when the -40 to
> +85 C operation is considered. So, proposal A would put the wider
> wavelength band at 1560nm to 1580nm.
>
>
>
> Of course, this choice would make co-existence with the video overlay
> impossible, with zero guard-band to the video band at 1550 to 1560nm.
This
> defeats the ¡®common ONT¡¯ idea, since it is impossible to make such an
ONT.
>
>
>
>
> Supposing we want to consider the coexistence with video for these
classes,
> then we must push the wavelength longer. Starting at 1574, we could
expand
> to a 1594nm. This is rather strange, having a center wavelength at 1584,
> which is nearly the ¡®anti CWDM grid¡¯. We could call this proposal B.
>
>
>
> On this alternative, we have sacrificed the compatibility with those OTDR
> filters we heard about. This raises an inescapable conclusion: to broaden
> the band, we will sacrifice either the video overlay or the compatibility
> with certainly legacy OTDR filters. It should be noted that there are
even
> fewer system deployments with this particular OTDR constraint than the
video
> overlay.
>
>
>
> Combining the two motivations above, we turn to the next longer CWDM
> wavelength: 1590nm. This would define the band to be 1580 to 1600nm;
called
> proposal C. In most PONs, this wavelength has no difficulties of
> transmission. It also provides a 20nm guard-band from the video, which is
a
> little better than the 14 nm with the narrow plan. It is disjoint with
the
> narrow plan; however, it is in a part of the spectrum where the narrow
plan
> seems not to care. So, we could build an ONU that responds from 1576 to
> 1600, and that would receive both signals. This is probably not the most
> practical solution, but at least it is possible.
>
>
>
> So, that¡¯s sort of what we have:
>
> Option A: 1560 ~ 1580nm
>
> Option B: 1574 ~ 1594nm
>
> Option C: 1580 ~ 1600nm
>
>
>
> I¡¯ll stop at this point, and leave the ¡®floor¡¯ open for comments.
>
>
>
> Sincerely,
>
> Dr. Frank J. Effenberger ¸¥À¼¿Ë °£·Ò²©¸ñ
>
> Huawei Technologies USA
>
> 1700 Alma Drive, Plano TX 75075
>
> Office (732) 625 3002
>
> Cell (908) 670 3889
>
>
>
>
--
Ken-Ichi Suzuki
NTT Access Network Service Systems Labs.
E-mail:kenyichi@ansl.ntt.co.jp
Tel:+81-43-211-3189/Fax:+81-43-211-8250