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$B%F!W(Bos 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, $Beb!Vq|(e$Aeb!Vec!"(B 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