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Dear all,
looking at this thread, I just can't help thinking that it is getting close to nowhere, with both sides presenting valid arguments in favor of their preferred solutions. I think that we should sit down together and discuss that face to face rather than continuing this counterproductive squabble. If we want th standard to move forward, we need to overcome the differences in the opinion regarding this issue. Since we all know the pros and cons of both solutions, I suggest all people interested in this topic have a meeting (lunch, dinner You name it) and discuss that face to face. Perhaps there is some way to build consensus around this particular issue.
Any comments on the proposal ?
BR
Marek Hajduczenia (141238)
NOKIA SIEMENS Networks S.A. - COO BBA DSLAM R&D
Rua Irm?os Siemens, 1, Ed. 1, Piso 1
Alfragide, 2720-093 Amadora, Portugal
* marek.hajduczenia@nsn.com
<mailto:Marek.Hajduczenia@siemens.comhttp://www.marekhajduczenia.info/index.php> (+351.21.416.7472 4+351.21.424.2082
________________________________
De: ext Kim Bong Kyu [mailto:bongkim@etri.re.kr]
Enviada: s?b 10-11-2007 6:03
Para: STDS-802-3-10GEPON@LISTSERV.IEEE.ORG
Assunto: Re: [8023-10GEPON] PR-20 Performance comparison between 1550nm and 1590 nm
Dear Dr. Otaka and Dr. Marek,
I appreciate your comments.
As the downstream wavelength, we believe that 1550 nm wavelength is better than 1590 nm with respect to not only availability but also performances.
However, I think that it is a little difficult for us to get the exact value of the performance
because of the lack of our knowledge and too fast changing in technology.
For transmission Loss,
I used the IEC standardization which describes the transmission loss only for 1550 nm and 1625 nm.
So I estimated that it would increase linearly as the wavelength increases from 1550 nm to 1625 nm.
However, I find out that there is no significant difference between 1550nm and 1590nm by Marek' good advice.
Thank Marek for your comment to correct me.
For the bending loss,
The bending radiuses of 25 mm and 30 mm have been considered for the outdoor plant (such as backbone, longhaul system) as you know.
In recent, the bending losses of 5 mm, 10 mm, 15 mm radius are discussed in the ITU-T G.657 for access network.
However, I think that it is a little difficult to make a common rule for many different service providers.
So I just bring a guideline of a Korean service provider to our presentation.
They limit the bending to less than 3-turns with 10mm radius in the indoor plant(or from MDF to ONT).
That is why we use 2-turns with 10mm radius in our presentation.
I think that NTT can have a different policy to deal with the problem.
If we choose the 1550 nm wavelength, we can have the following benefits
- we can use a standard SMF instead of a bend insensitive/improved fiber. (it may more economic)
- if a bend insensitive/improved fiber is used, 1550 nm wavelength allows more turns of bending and more flexibleness.
Sincerely yours,
Bong Kyu Kim, Ph.D.
Senior Research Staff
Optical Access Tech. Team
BcN Research Lab.
Electronics and Telecommunications Research Institute
Tel: +82-42-860-1344, Fax: +82-42-860-5213
E-mail: bongkim@etri.re.kr
-----?? ???-----
?? ??: "Akihiro Otaka" <ootaka@ANSL.NTT.CO.JP>
?? ??: 2007-11-08 ?? 9:43:23
?? ??: "STDS-802-3-10GEPON@LISTSERV.IEEE.ORG" <STDS-802-3-10GEPON@LISTSERV.IEEE.ORG>
??:
??: Re: [8023-10GEPON] PR-20 Performance comparison between 1550nm and 1590 nm
Dear Marek,
This is Akihiro Otaka.
Thank you for your quick commnt and information.
What I'd like to say in my e-mail is just;
- we have no common values for small size bending loss
- I don't know the presentation shows the typical bending case
or not.
- so detail discussion such as "2 to 3dB worse" is not useful for us.
P.S.
I am interested in the reason why 10 mm and 2-turns,
as one operater member not as a task force member.
P.S.2
for your information;
In our case, we design our ODN loss using "end of life" values.
The attenuation, connetor loss and variation are a little bigger
than the commonly used values.
And fiber rerouting margin is also considered, because in the very
long years of operation, we often have to change fiber route.
I think every carriers are using different values for their designing.
Best regards,
Akihiro Otaka
NTT
At 20:36 07/11/08, Hajduczenia, Marek wrote:
>Dear Otaka-san,
>I believe it does not. We DO NOT need to specify the bending radius for the
>cable plant - it is completely out of the scope of the TF as You also
>pointed out. We see only power budget as a whole and if some vendor deploys
>fibre plant with 10 mm bend radius, they will have to suffer the incurred
>loss. We cannot simply afford to get into such details in our group -
>otherwise we will end up doing the specifications which are useless and do
>not find practical application.
>As for the attenuation difference between 1550 and 1590 nm as included in
>the presentation, according to fibre measurement data collected and
>compiled by Pete Anslow >
>http://www.ieee802.org/3/hssg/email/msg00869.html, the fibre has
>attenuation of 0.277 dB/km and 0.276 dB/km for 1550 and 1590 nm windows,
>respectively. I fail to see how that is compliant with the measurements You
>present. Pete's data is a relatively large sample of various cable plants
>and even if the values are expected to be higher in PON plants (worse
>splices??, more splices ??, connectors ??), definitely it is hard to expect
>2-3 dB power budget difference which is stated in the presentation. That
>would require at least 0.1 dB/km difference between 1550 and 1590 nm in
>favour of 1550 nm window at the material properties level, assuming both
>plants are prepared in the very same way. The data I have and which is
>quoted as reliable by various people (Pete and Piers are not afraid to put
>their names under that)!
> suggests otherwise. I would say such an argument will not hold. I agree
>with the worse bend loss parameters as quoted, though again the indicated
>difference is slightly exaggerated - the ODNs I had a chance to see had
>fibre bent with at least 30 mm radius to avoid excessive loss. I do not see
>a valid reason to go below that value, unless really tight ducts are
>available, which is quite uncommon.
>Since the upstream channel loss is dominant in the system we design, You're
>right - we have to assure upstream channel works (0.466 dB/km according to
>Pete's data). That is significantly lower than the 1550/1590 nm windows.
>Best wishes and thank You for keeping the topic rolling
>Marek Hajduczenia (141238)
>NOKIA SIEMENS Networks S.A., Portugal - R
>Rua Irm??os Siemens, 1
>Ed. 1, Piso 1
>Alfragide
>2720-093 Amadora
>Portugal
>* Marek.Hajduczenia@siemens.com
>http://www.marekhajduczenia.info/index.php
>(+351.21.416.7472 4+351.21.424.2082
>"C makes it easy to shoot yourself in the foot; C++ makes it harder, but
>when you do, it blows away your whole leg." - Bjarne Stroustrup
>
>-----Original Message-----
>From: ext Akihiro Otaka [mailto:ootaka@ANSL.NTT.CO.JP]
>Sent: quinta-feira, 8 de Novembro de 2007 10:26
>To: STDS-802-3-10GEPON@LISTSERV.IEEE.ORG
>Subject: Re: [8023-10GEPON] PR-20 Performance comparison between 1550nm and
>1590 nm
>
>Dear Bong Kyu Kim,
>
>This is Akihiro Otaka.
>Thank you for the slide.
>
>I have just one comment about fiber loss.
>
>I understand that the IEC standard say nothing about macrobending
> loss of r=10mm. Therefore, the value of r=10mm should be a
>vender specific value. These values may be different from venders.
>And I think that some venders may not guarantee such values,
>and that some venders may guarantee the smaller value.
>I don't think the discussion based on such kind of value is usefull.
>And if we use the value of r=30mm shown in the standard,
>there is no difference between 1550 nm and 1590 nm.
>
>Of course, in the real installation, you can allocate 20dB CHIL for
>any kinds of loss in ODN. I think it is out of scope of the task
>force.
>
>And the transmission loss of 1590 nm and 1260 nm is nearly
>the same. So, in my understanding, I have to design the ODN loss using
>1260 nm, whether 1550 nm or 1590 nm.
>
>Best regards,
>Akihiro Otaka
>NTT
>
>
>At 23:08 07/11/07, ????????? wrote:
>>
>>Dear All,
>>
>>Sorry! Once more for clear title.
>>
>>In our knowledge, 1550 nm wavelength has better performance than 1590 nm
>>wavelength.
>>The attached file is our proposal for wavelength plan for PR-20.
>>Please let me know if you have any comment on the proposal.
>>
>>Sincerely yours,
>>
>>Bong Kyu Kim, Ph.D.
>>Senior Research Staff
>>Optical Access Tech. Team
>>BcN Research Lab.
>>Electronics and Telecommunications Research Institute
>>Tel: +82-42-860-1344, Fax: +82-42-860-5213
>>E-mail: <mailto:bongkim@etri.re.kr>bongkim@etri.re.kr