Re: [8023-10GEPON] FW: Downstream wavelength
Hi Marek: I'm only commenting
on the cooling to keep the wavelength stable, since the need to cool devices
for efficiency is temporary.
Optical device efficiency gains follow
some type of curve not unlike Moore's Law for device density.
At some point in the future, devices
which were previously impossible become possible (Think 1watt white
LEDs now being used for street lighting,
and backlighting for LCD screens).
If one removes the cooling requirement
to make reliable output power possible as an issue (which time will
do by itself)
you are left with the cooling needed
to control wavelength drift. The passage of time will not remove that requirement
barring some unforeseen technology breakthrough.
Cooling needed to control wavelength
drift will always be there, unless somebody comes up with a very clever
idea that negates the
physical size changes of optical materials
over temperature. That would be an unpredictable breakthrough which
is unwise to count on,
whereas accommodating future efficiency
increases based on a historical precedent of efficiency increases over
time by creating a path for them would be wise.
If you make the wavelength requirement
dependent on cooling all the time, you build in complexity, higher consumed
system power and cost forever,
whereas, if you make the wavelength
specification broad, you then only need cooled devices as long as they
are inefficient. This would then make it
an incentive to develop/use more efficient
devices.
I hope this helps.
Best Regards
Maurice Reintjes
MindspeedTM
Hillsboro, Oregon,USA
Office Phone (503)-403-5370
Mobile (503)-701-0797
| Marek Hajduczenia <marek_haj@xxxxxxx>
11/05/2008 03:12 PM
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| Re: [8023-10GEPON] FW: Downstream wavelength |
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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]
Sent: quarta-feira, 5 de Novembro de 2008 12:49
To: STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
Subject: Re: [8023-10GEPON] FW: Downstream wavelength
Hi Victor: I appreciate your comments, as they describe the existing
conditions in the end solution space.
To that end I support your comments, and position which is also advocated
by Jim Farmer.
My rational is that optical sources do not need to be so expensive and
tightly temperature controlled when you can use the 1580-1600nm band,
and when you remove the tight wavelength requirement, optical , sources
get cheaper, and thus increase the chances of wide
acceptance as was the case of 1GEPON, which uses low-cost optics.
Allowing a wider wavelength range also consumes less power, and can be
viewed as being more "green"; something which was not
a direct component to the initial PAR, but should be a factor that all
engineers take in to account when developing a new standard.
Best Regards
Maurice Reintjes
MindspeedTM
Hillsboro, Oregon,USA
Office Phone (503)-403-5370
Mobile (503)-701-0797
| Victor Blake <victorblake@xxxxxxx>
11/04/2008 06:21 PM
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Please respond to
Victor Blake <victorblake@xxxxxxx> |
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| Re: [8023-10GEPON] FW: Downstream wavelength |
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Jim,
As an early supporter of 10GigEPON (starting at the CFI) I am writing to
the task force to express my support for your proposal. I believe that
the 1580-1600nm wavelength would be more appropriate for use in the North
American and in particular US MSO market. This market is composed of operators
have existing wavelengths in use of their plant. Some already have substantial
EPON deployments.
As you have pointed out, 1577 (1574-1580nm) could be substantial problem
for MSOs. Having the second wavelength available for this market need would
help to avoid a conflict between 10GigEPON and broadcast video – to which
10GigEPON would surely loose out. If the task force were to elect to keep
1590nm out of the plan, they would be spelling out certain disaster for
10GigEPON as we know specifically of the efforts to use 1590nm for current
proposals for a next generation GPON solution. The result of keeping 1590nm
out of 10GigEPON would be to force the MSO industry to GPON. I’ll just
assume that is not the goal of the 10GigEPON Task Force, but it nevertheless
would be the most likely outcome.
In fact it is no surprise to find that the GPON vendors are the ones most
supportive of this proposed change.
I’ve communicated with a number of major US MSOs about this issue. The
three I have directly received responses from all support 1590nm and wish
to continue to see it as their first choice. Although these organizations
are not directly represented in the IEEE today, they have from time to
time participated in the past, and are certainly the largest EPON and 10GigEPON
market in North America currently. For this reason, I urge the task force
members to reach out to the MSO community and solicit their opinions if
you do not already know where they stand.
Victor Blake
Independent Consultant
From: Jim Farmer [mailto:Jim.Farmer@xxxxxxxxxxxxx]
Sent: sábado, 1 de Novembro de 2008 15:59
To: STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
Subject: [8023-10GEPON] FW: Downstream wavelength
We request to make the attached presentation
during the 10GEPON meeting in Dallas. We remain concerned over the
decision to drop the 1590 nm downstream band from the plan, for reasons
shown in the attached. Note that there are notes that go with most
of the slides. You can see them by going to View|Notes Page
Thanks,
Alan Brown
Jim Farmer
Jim Farmer, K4BSE
Chief Network Architect,
Enablence Technology
FTTx Networks Division.
1075 Windward Ridge Parkway
Alpharetta, GA 30005 USA
678-339-1045
678-640-0860 (cell)
jim.farmer@xxxxxxxxxxxxx
www.enablence.com
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