Re: [8023-10GEPON] Updated optical power budget presentation
Dear Takizawa-san and All,
There is a little bit of detail with this ER issue. Let me explain:
The power levels listed in the charts are "ITU average power" values.
Because they are average power, they need an ER to go along with them.
That ER is the "Nominal ITU ER", which we have set to 9 dB. Keep in mind
that both of these values are intended to be Informative values. They are
used on these slides merely because most people like to think about optical
levels in terms of an average power and a 'normal' ER.
In the spreadsheet, what happens is that the Average Power and the Nominal
ER are used to calculate the Optical Modulation Index (OMI). It is the
intention that the OMI will be the normative requirement of the system.
After all, it is the OMI that really matters!
So, with the normative OMI specified, all we need to add is a normative
minimum ER limit, just to make sure that somebody doesn't try to make a
transmitter that has a really bad ER. This ER limit would likely be 8 dB
for the OLT transmitter, and 6 dB for the ONU transmitter. But, it must be
noted that the ER limit does not appear in any of the other equations in the
link model, so it is more of an engineering common sense limit.
I will clarify all of this in the next draft.
On a related note, I will be copying snapshots of the link budget
spreadsheet into this presentation, and that will help to clarify exactly
how we are using these values.
Sincerely,
Frank E.
-----Original Message-----
From: Motoyuki TAKIZAWA [mailto:mtaki@ACCESS.FUJITSU.COM]
Sent: Friday, November 02, 2007 3:47 AM
To: STDS-802-3-10GEPON@LISTSERV.IEEE.ORG
Subject: Re: [8023-10GEPON] Updated optical power budget presentation
Dear Frank,
Thank you for compiling the proposal.
In your Power Budget table, you have defined the Extinction
Ratio of 9 dB. For the downstream, it is OK assuming EML TX in
OLT. But for upstream, a direct modulation DFB TX in ONU is
assumed and ER would be worse than the EML, down to 6 dB.
I think the power budget table should have ER column, which
indicates each ER 9dB for Downstream and 6dB for Upstream in
it.
With that change, I would like to be a supporter of your
presentation.
I hope the power budget will be smoothly approved in the next
Atlanta meeting.
Sincerely,
Motoyuki Takizawa
On Thu, 1 Nov 2007 16:28:41 -0400
Frank Effenberger <feffenberger@HUAWEI.COM> wrote:
> Dear All,
>
> Attached is a new version of the optical power budget presentation.
>
>
>
> Change notes:
>
> 1. The technical values have not changed since the last version.
>
> 2. Added a page to hold supporter。ッs names.
>
> 3. Added a page of 。ョconditions。ッ which gives the key definition
elements of
> the budget numbers, and requirements on the FEC algorithm.
>
> 4. Added a page that refers to the optical budget spreadsheet that holds
the
> exact calculation of the budget.
>
> (Note: this document will be coming soon.)
>
>
>
> If you would like to sign on as a supporter of this position, please let
me
> know.
>
>
>
> Sincerely,
>
> Dr. Frank J. Effenberger ク・タシソヒ ー」キメイゥク〓>
> Huawei Technologies USA
>
> 1700 Alma Drive, Plano TX 75075
>
> Office (732) 625 3002
>
> Cell (908) 670 3889
>
>
>
--
Motoyuki Takizawa
Fujitsu Access Ltd. R&D Center