Thanks for the good comments on this thread. We would like to add a
bit more clarification or our position before we meet next week.
We believe that PR(x)30 can stay at 1577 nm. We would like to see the
ability to operate PR(X)10/20 on 1590 +/-3 nm. We would like to say
1590 +/-10 nm, but this is not feasible. It requires a wider filter
bandwidth, which is more difficult, as has been pointed out. This is
one of the reasons why we reduced the proposed occupied bandwidth of
the 1590 nm option to +/-3 nm, even though this requires a cooled
laser at the OLT.
We have reviewed the presentations from May 2007. While we agree in
principle with the presentations, it seems that they do not take into
consideration initial wavelength calibration of the filter, nor do
they take into account temperature drift of the filter. And since the
filter in question is at the ONU, it must be very low in cost. A
filter designed for either 1577 nm or 1590 nm must be wider than the
occupied wavelength range of the laser, in order to account for
initial calibration accuracy of the filter, and the temperature drift.
When we added these effects, the transition region of a 1577 nm filter
(which must attenuate the 1550 nm broadcast signal), became
unacceptably small. The transition region for a 1590 nm filter went to
14 nm, which is tight but might be possible at ONU prices. This is
what we show on the slides we sent to the reflector earlier, and which
we seek permission to present in Dallas.
We have been talking to filter experts about how to make low cost
filters that will meet the requirements. One of the experts we have
consulted is our parent company's Dr. Matt Pearson in Ottawa. I quote
Dr. Pearson below (with his permission, I have modified his words to
try to stay within IEEE guidelines, while not changing his meaning).
Referring to Frank Effenberger's comments (added below), Dr. Pearson
writes:
/"He's correct in his comments - 6 nm is definitely easier than 20 nm
(which is why we recommend it in Jim's proposal!). /
//
/"He is also correct that both the filters and lasers are available to
meet these specs. (DWDM relies on that!). Our concern is more related
to the costs, where DWDM costs are outrageous, even CWDM costs are too
high for FTTH. So we need noticeably easier specs than CWDM. In fact,
I would argue that we need noticeably easier specs than today's
FTTH..! -- There are so many more expensive aspects to 10G than 1.25G
(DFB, APD, 10G electronics, extra blocking filters, etc), that if they
want any hope of getting optics at a reasonable cost then they have to
compromise something somewhere.../
//
/"Thin films and DFB lasers can meet either spec. We believe (certain)
PLC technology can also meet either spec. But some other PLC
approaches ... would quite likely never meet these 10G specs.. So
again, it limits the pool of available suppliers and available
technologies that could otherwise help bring down costs for systems
people. /
//
/"Either way, we will make it work. We're just trying to make (the
cost of the ONU lower)..."/
//
Thanks,
jim farmer
Alan Brown
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
*From:* Frank Effenberger [mailto:feffenberger@xxxxxxxxxx]
*Sent:* Thursday, November 06, 2008 3:01 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
<mailto:STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx>
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
Victor,
I doubt that. >90% of EPON is deployed in Japan, so you can’t neglect
their OSP and the huge influence this has on part volumes.
Back to the Mike’s suggestion – while it is a good idea, it will work
if the big concern is the transmitter specifications.
However, the latest comment from Jim Farmer regards the filters at the
ONU receiver. And defining a super-set of the bands doesn’t help there.
Actually, in my opinion, neither the filters nor the lasers are that
big of a deal. I’m not sure where Jim’s filter data come from, but
there are pretty standard thin-film filter designs that can achieve
the sharpness, accuracy, and temperature stability that we need for
14nm of guard band. Our task force actually got a model of this back
in May of 2007. Actually, one of the considerations in the difficulty
of making these filters is the width of the pass band, and it is
actually easier to make a 6nm width pass band than a 20nm pass band.
Sincerely,
Frank E.
------------------------------------------------------------------------
*From:* Marek Hajduczenia [mailto:marek_haj@xxxxxxx]
*Sent:* Thursday, November 06, 2008 3:24 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
Hi Victor,
That is how Mike sees it. That does not need to be necessarily how
things work out in the market. It seems to me that we are trying to
guess which direction the market goes and I think we all agree that is
hardly predictable. Additionally, if I recall right, we are not
allowed to discuss market shares so probably it is better to leave it
at this ...
Regards
Marek
------------------------------------------------------------------------
*From:* Victor Blake [mailto:victorblake@xxxxxxx]
*Sent:* quinta-feira, 6 de Novembro de 2008 13:13
*To:* marek_haj@xxxxxxx; STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* RE: [8023-10GEPON] FW: Downstream wavelength
To chmine in here – I’d have to say that to me it sounds like the 1577
is the exception, not the 1590.
-Victor
*From:* Marek Hajduczenia [mailto:marek_haj@xxxxxxx]
*Sent:* Thursday, November 06, 2008 12:06 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
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]
*Sent:* Wednesday, November 05, 2008 8:53 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
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
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
------------------------------------------------------------------------
*From:* Frank Chang [mailto:ychang@xxxxxxxxxxx]
*Sent:* Wednesday, November 05, 2008 7:06 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
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]
*Sent:* Wednesday, November 05, 2008 3:22 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
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]
*Sent:* Wednesday, November 05, 2008 6:12 PM
*To:* STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
*Subject:* Re: [8023-10GEPON] FW: Downstream wavelength
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
Please respond to
Victor Blake <victorblake@xxxxxxx>
To
STDS-802-3-10GEPON@xxxxxxxxxxxxxxxxx
cc
Subject
Re: [8023-10GEPON] FW: Downstream wavelength
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 <file:///%5C%5Cwww.enablence.com%5C>
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