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Hi Mike,
thanks for sharing Your point of view with us.
Please confirm whether I understand You right. You say that
we should go with a wider window and carriers may require vendors to actually
build equipment which complies to a certain part of this sub-band. In our case,
we could hypothetically specify a downstream band between 1574 and 1600 nm while
e.g. a narrow band option between 1574 and 1580 nm could be required by some
carriers to remain compliant with their ODN. Is this what You're trying to relay
in Your email ? Please confirm
Thank You
Marek From: Mike Dudek [mailto:Mike.Dudek@xxxxxxxx] Sent: quinta-feira, 6 de Novembro de 2008 10:22 To: STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx Subject: Re: [8023-10GEPON] FW: Downstream wavelength As an outsider to
10GEPON, but member of IEEE 802.3 working group I?d like to suggest that the
IEEE standard should be working to provide the best solution for the new future
installs of the IEEE standard while paying attention to the existing
infrastructure. When you come to a point that you are
having to drive the cost of the new standard higher in order to be compatible
with existing infrastructure that may or may not exist in many applications I?d
suggest that the IEEE standard should work for the long term low cost solution,
while making it technically feasible for people with the existing infrastructure
to add additional requirements to make it compatible with their existing
infrastructure. That way you do not burden the long term cost of new
installs. EG if the low cost solution needs a Tx window
of xnm to x+30nm but for compatibility with a non-IEEE standard can only be xnm
+10nm, then the IEEE spec should be xnm to x+30nm and individual vendors that
are using the non-IEEE standard can impose the tighter (subset spec) of xnm to
xnm +10nm. (This obviously only applies if the PAR and objectives
have not made compatibility with the non-IEEE standard a requirement.).
Please note my example is for illustration only the numbers in it
are not meant to apply to this specific question. From: Jim
Farmer [mailto:Jim.Farmer@xxxxxxxxxxxxx] My primary concern is
that the 1577 nm downstream wavelength is inconsistent with use of the 1550 nm
broadcast (auxiliary) wavelength. The problem is that the two wavelengths
are too close together to allow us to build economical filters at the ONU to
separate the two wavelengths. It is a little easier with the 1590 nm
wavelength, though it is still difficult. Originally I wanted to specify
the wavelength band as 1580 - 1600 nm as it was originally. But I found
that when I put in real filter characteristics, I still had an extremely narrow
transition region for the filter. So I accepted that we would have to
narrow the transmit window. I chose +/-3 nm (1587 - 1593 nm) following the
reasoning for PR(X)30. We are adding cost to the laser, but at the OLT,
which is not as cost sensitive as is the ONU. I also had to accept
that the auxiliary wavelength was limited to 1550 - 1555 nm, even though
commercial practice is to use wavelengths up to almost 1560 nm. People may
complain about this restriction, but I think in the end they will live with
it. Unfortunately I have
not been able to get quantitative information on the filter complexity - I would
like to see filter vendors jump in with comparative numbers. Some vendors
I spoke with gave me more pessimistic numbers than I used in preparing the
slides. So the application is
for anyone who wants to use the 1550 nm broadcast wavelength. This is the
only way I see to possibly make use of 1550 nm overlay practical. And it
still demands a more difficult filter than we demand currently. But
presumably advances in the state-of-the-art will made the filter practical at
some point. Thanks, jim Jim
Farmer, K4BSE From: Frank
Chang [mailto:ychang@xxxxxxxxxxx] I just reviewed this
thread, and my interpretation to Jim?s slides is that-
1)
The argument is not for
PR(X)30 as cooled TX is assumed because of tight power budget, so narrower
1577nm band considered feasible for PR(X)30. 2)
For PR10/20, possibly
uncooled optical sources are assumed, so bring about the argument that larger
wavelength band, such as wider 1590nm band, is only feasible.
To satisfy this
argument, basically call for the group to switch back to the wavelength plan
originally specified in D2.0. So actually we are re-visiting the argument the
group made during the baseline stage a year ago. Jim- Can you confirm
this is what you are looking for? As it is clear the
PR(X)30 will be assumed mainstream deployment which requires co-existence with
installed 1G version, can anybody elaborate the scenarios on how PR10/20 going
to be deployed? My question is weather PR10/20 scenarios has to use cooled or
semi-cooled optical source?
] thanks Frank C.
From: Frank
Effenberger [mailto:feffenberger@xxxxxxxxxx] To pile onto this
thread, I have a question regarding Jim Farmer?s most recent presentation and
Maurice?s support of it: Did you notice that
Jim?s presentation is asking to change the PR10/20 OLT transmitter wavelength
range to 1587 to 1593nm? (At least, that is how
I read it, but I should say that the exact numbers are not clear.)
Perhaps Jim can clarify
exactly what he is asking for? that would be helpful.
Sincerely, Frank
E> From: Marek
Hajduczenia [mailto:marek_haj@xxxxxxx] Hi Maurice,
Just following the
arguments You used in Your email: does that mean that You see PR(X)20 OLT
transmitters as uncooled devices? Are the power levels we are targeting
achievable using uncooled optics? As far as I understand, cooling is necessary
not only to keep the central wavelength within the predefined range but also
assure higher output power level. Can You comment on
this? Regards Marek From: Maurice
Reintjes [mailto:maurice.reintjes@xxxxxxxxxxxxx]
We request to make the attached
presentation during the 10GEPON meeting in Thanks, Jim Farmer, K4BSE |