Dear Marek and Tsutomu:
Here is the reference:
ECOC 2006, paper We4.5.7:
Analysis on SRS-Induced Performance
Impairment of Downstream Data Signal in Video Overlay EPON Systems
A. Agata | A. Murakami | Y. Horiuchi
KDDI R&D Laboratories Inc., Saitama , Japan
To quote (and add to) the conclusion from the paper:
…we have found that the impact of AC
crosstalk (from SRS) on downstream data signal (at 1490 nm) exceeds 0.1dB on average only when these
conditions as follows are satisfied simultaneously: (1) PRF (optical launch power at 1550 nm) becomes
~18dBm or more, (2) RF video signal contains VHF component (that is operates in the ~<100 MHz region),
and (3) OMI (optical modulation index)
of the VHF component in the optical RF signal becomes more than ~10%.
The authors show that cross talk from a
discrete RF tone in the video domain onto a baseband GbE signal, can result in
a power penalty. This is in addition to any loss in optical power suffered by
GbE signal due to SRS.
In the case of 10GEPON:
(1) The crosstalk would be 1545(?)nm <->
1550nm XPM instead of 1490(?)nm <-> 1550nm SRS. The relative magnitude
of these effects can be seen in M. R. Phillips, et al., J. Lightwave Technol.,
vol.17,
(1999), pp1782-1792.
(2) Instead of a ~ 10% RF subcarrier at ~
50 – 100 MHz, the RF “tones” (typically two) are in the 2 – 10 GHz range. The
tones are chosen such that f1-f2, f1-2*f2, 2*f1-f2, f1-2*f2, etc lie outside of
the CATV signal band (50-870 MHZ). Typically the frequencies of the tones may
be in the 2 and 6 GHz ranges. The tones can result from phase and or intensity
modulation of the source laser, and the resulting RF power is usually much
higher than any one CATV RF sub carrier. (Laser chirp + fiber dispersion
rapidly convert pure phase modulation into intensity modulation)
I have not carried out experiment or attempted
to calculate this effect. I will be in Monterey
next week and will be happy to discuss this topic over a beer.
David Piehler
Alphion
mobile: +1 732 692 4581
From: Hajduczenia, Marek
[mailto:marek.hajduczenia@SIEMENS.COM]
Sent: Wednesday, January 10, 2007
12:18 AM
To:
STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON]
[Channel link model ad-hoc]
Dear David,
Would You be so kind and provide the
complete reference for the said paper ? I am also curious but a broad search is
lengthy - I am sure we could benefit from this publication if we could identify
which one it is ..
Regarding the issue number 2: what we are
interested in is the impact of the video overlay signal on the digital
transmission rather than trying to model the RF channel transmission in the
1550 nm band. The video overlay is not an obligatory part of the standard and
as far as I know, current IEEE 802.3 does not specify the parameters of the
video overlay apart from the statement that the 1550 nm band is reserved for
other services. As such, I believe that the 10G standard should go the same way
and focus on the EPON PHY rather than on the RF overlay specifications, which
are outside of the scope of our PAR.
Thank You for Your comments. I would
appreciate if You had a look at the modelling of the SBS and SRS once the
updates spreadsheet is released and shared Your thoughts with us ...
Best wishes
From: TATSUTA
[mailto:tatsuta@ANSL.NTT.CO.JP]
Sent: quarta-feira, 10 de Janeiro
de 2007 2:42
To:
STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON]
[Channel link model ad-hoc]
Dear David,
(1) I would not be so quick to dismiss XPM. 々PM
gets stronger as delta lambda gets small, and at higher RF frequencies. ！t’s
not well known but most video signals have or less discrete, high modulation
index, phase and/or intensity tones in the 2 ？10 GHz range. ゝhese
are used for SBS suppression, and they vary significantly among vendors.？I
have not done any calculations, but there was a paper at ECOC this year from
KDDI that showed that cross-talk from RF carriers could add a penalty ？aside
from power loss.
I looked for a paper you suggested, but I did not find it.
Anyway, if it is true, I agree with your comment.
(2) Is there any need to define the acceptable
degradation on the video signal?？This is perhaps the most
significant issue with the B/GPON RF video overlay.？I am not concerned with
power loss (or gain) but rather the effective increase in RIN (mediated by
either XPM or SRS), or by discrete RF interference from idle fames again
mediated by XPM and/or SRS.？(Incidentally would these idle
frames be in phase if you had several 10G DWDM signals originating from the
same switch/router?
I do not think it is an issue of the channel link model, because we can not put
it on the spread sheet and also it is an implementation issue of RF-ONU.
However, if we can consider it when we decide the output power level of
10GE-OLT and wavelength allocation of a downstream signal, it is good for us.
Sincerely yours,
Tsutomu TATSUTA
At 02:02 07/01/10, David Piehler wrote:
Just a few comments 〓
(1) I would
not be so quick to dismiss XPM. 〓XPM gets stronger as
delta lambda gets small, and at higher RF frequencies. 〓It’s not
well known but most video signals have or less discrete, high modulation index,
phase and/or intensity tones in the 2 〓 10 GHz range. 〓These
are used for SBS suppression, and they vary significantly among vendors.〓 I have
not done any calculations, but there was a paper at ECOC this year from KDDI
that showed that cross-talk from RF carriers could add a penalty 〓 aside
from power loss.
(2) Is there
any need to define the acceptable degradation on the video signal?〓 This is
perhaps the most significant issue with the B/GPON RF video overlay.〓 I am
not concerned with power loss (or gain) but rather the effective increase in
RIN (mediated by either XPM or SRS), or by discrete RF interference from idle
fames again mediated by XPM and/or SRS.〓 (Incidentally would
these idle frames be in phase if you had several 10G DWDM signals originating
from the same switch/router?
I am not trying to open a big can of worms here, and my feeling is that these
effects are probably negligible, although measurable.
David Piehler
Alphion
mobile: +1 732 692 4581
From: Hajduczenia, Marek [mailto:marek.hajduczenia@SIEMENS.COM]
Sent: Tuesday, January 09, 2007
3:56 AM
To:
STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON]
[Channel link model ad-hoc]
Dear Tatsuta-san,
Thank You very much for Your contribution. I found it useful and if there is no
problem with it, I would like to reuse part of Your conclusions in the
introductory section of the presentation on the ad-hoc activities.
I agree with Your conclusions and I believe that the updated Excel spreadsheet
will contain SBS and SRS power penalties - SRS is completed while SBS is still
under examination to achieve 0 - order approximation with reasonable quality.
The presentation will be distributed today and I will ask for
the potential supporters of the conclusions and implementation.
The updated Excel spreadsheet will also be distributed in due time on the
reflector ...
Best wishes
Marek Hajduczenia (141238)
SIEMENS
Networks S.A. - IC COM D1 R
Rua
Irm〓os Siemens, 1
Ed. 1, Piso 1
Alfragide
2720-093 Amadora
Portugal
* Marek.Hajduczenia@siemens.com
http://marekhaj.easyisp.pl/index.php
(+351.21.416.7472 4+351.21.424.2082
From: TATSUTA [mailto:tatsuta@ansl.ntt.co.jp]
Sent: ter〓a-feira, 9
de Janeiro de 2007 6:32
To: Hajduczenia,
Marek; STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON]
[Channel link model ad-hoc]
Dear Marek and all,
I summarized the influence of RF signal as attached.
My conclusion is following;
1. SRS and SBS should be studied.
2. XPM does not need to be considered, if a wavelength of 10G-EPON downstream
is separated in 5nm or more from RF signal wavelength.
3. The other items do not need to be considered, unless S/X value of ONU input
point is specified in the standard body (I do not think we specify it.). I
think S/X is implementation issue.
Sincerely yours,
Tsutomu TATSUTA
At 21:41 07/01/04, Hajduczenia, Marek
wrote:
Dear Sergey,
I would appreciate any help You can provide me with. I have some formulas to
estimate the impact of the video channel overlay on the downstream and upstream
channels but I have a very hard time trying to figure out how to calculate /
estimate the values of individual parameters.
Do You have any idea how to apply the formulas with the set of parameters that
we have in the Excel spreadsheet?
Best wishes
Marek Hajduczenia (141238)
SIEMENS Networks S.A. - IC COM D1
R
Rua Irm縊s
Siemens, 1
Ed. 1, Piso 1
Alfragide
2720-093 Amadora
Portugal
* Marek.Hajduczenia@siemens.com
http://marekhaj.easyisp.pl/index.php
(+351.21.416.7472 4+351.21.424.2082<?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" />
From: Ten, Sergey Y [mailto:TenS@CORNING.COM]
Sent: quarta-feira, 3 de Janeiro
de 2007 19:32
To:
STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON]
[Channel link model ad-hoc]
Marek,
The impact of the RF overlay may be modeled (in zero
approxiamtion) as increased loss at data signal wavelength since Raman
scattering will transfer energy from digital signal to video signal.
In the next order approximation one has to take into account transfer
of the modulation.
I can help you with taking into account zero approximation.
SergeyFax +1 607 974 4354
-----Original
Message-----
From: Hajduczenia,
Marek [mailto:marek.hajduczenia@SIEMENS.COM]
Sent: Wednesday, January 03, 2007
11:14 AM
To:
STDS-802-3-10GEPON@listserv.ieee.org
Subject: [8023-10GEPON] [Channel
link model ad-hoc]
Dear all,
since there was no
activity in the said ad-hoc for some time, I decided to run the first update of
the channel link model spreadsheet (please find it attached in a zipped form -
10GEPON-D.0.0.zip). The main changes included in this release are as follows:
- the examined target range is always limited
from L_start to Target reach, with the granularity depending on the Target
reach value. The formula used to calculate the individual steps in column
[A18:A34] is defined as follows:
=(($L$3-$L$4)/16*(ROW($A18)-ROW($A$18))+$L$4)
- the resulting chart for power penalties versus
distance has now the auto ranges for X and Y /top value/ enabled - this
way the chart auto adjusts to the selected range
- L_step was removed since the granularity is
auto adjusted ...
- the "Add Ins Loss" parameter is now
calculated based on the split count for the PSC module used in the EPON
system. Cell L5 contains the split count (Split_count parameter). The cell
L8 value is calculated using the following formula:
=10*LOG(L5)+$AM$121*LN($L$5)+$AN$121, where the theoretical loss for N way
splitter are summed with the approximated excess loss, based on the
approximation curves estimated for typical, commercially available
splitters (Cell range [Y69:AL130]). The curve coefficients for average
expected splitter parameters are as follows: $AM$121 (A=0.5636) and
$AN$121 (B=0.3979) with the approximation curve of logarithmatic type:
A*ln(N)+B
To be added,
if required: changing the average splitter type into worst/best case scenario
values - preferably with the switch variables defined in the spreadsheet (may
be tough to find some space for that though :-9)
As for the other
parameters in the spreadsheet: as Dawe suggested previously, we should probably
examine the "TP4 offset cell" (T8) which currently follows "Tx
mask top" (G14) in similar style to 10GEPBud3_1_16a.xls. Dawe thinks that this
cell needs a thorough review and we should adjust its value in such a way that
it compensates for the upstream channel burst mode transmission.
Additionally, we should
try to numerate the impact of the optional video overlay channel on the overall
power budget. Is anyone willing to help me with that ?
Thank You for Your time
and attention
Best wishes
Marek Hajduczenia (141238)
SIEMENS
Networks S.A. - IC COM D1 R
Rua
Irm縊s Siemens, 1
Ed. 1, Piso 1
Alfragide
2720-093 Amadora
Portugal
* Marek.Hajduczenia@siemens.com
http://marekhaj.easyisp.pl/index.php
(+351.21.416.7472 4+351.21.424.2082