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Dear Tanaka-san, Thank You for the splendid presentation and high quality report on the progress of this particular ad hoc. IMHO, I would not like to see two wavelength channels standardized for downstream channel for a single reason: even though it is relatively easy to manufacture ONU modules with different wavelengths (change of complete optical subassembly with laser, filters and receiver), it may cause stock problems and accidental mix-up when a system set up to operate with 10G downstream in 1480-1500 nm window suddenly has an ONU which expects a downstream channel in the 1574-1580 nm band. The OLT would have to be also equipped with varying laser sources. As much as it is a practical solution, I do not know whether it is the best choice possible. I would rather stick with a single downstream band for the sake of simplicity and transparency of the system. As for the proposal of the filter structure in the presentation - I must say that the case-2 (see page 4 for example), will require pass band filter of quite super quality, which will have to be uniform for a large band (upstream 1310 window, downstream 1490 window, video 1550 window), then have a notch above 1570 nm and then again have minimum loss in the window above. I am concerned whether such devices can be designed in practice. At least what I gather from the work I did with Joao Santos, it is quite challenging to have a filter with a large flat top, then sharp, high isolation narrow band. This is mainly a practical concern - I do not know how such a structure will impact the other channels i.e. what will happen when the part of the video channel leaks into the 10G signal. Additionally, I did some minor editorial changes in the presentation. You can find it attached. In its current form, I am ready to support its conclusions. It would be beneficial also to add a slide on the proposed 2 option wavelength allocation system and consider its pros and cons. The topic came out already so we may as well tackle it in the right ad hoc group. Best wishes and thank You for Your time Marek Hajduczenia (141238) NOKIA SIEMENS Networks S.A., Portugal - R Rua Irmãos 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 -----Original Message----- From: Keiji Tanaka [mailto:kj-tanaka@KDDILABS.JP] Sent: quarta-feira, 2 de Maio de 2007 5:42 To: STDS-802-3-10GEPON@listserv.ieee.org Subject: [8023-10GEPON] Wavelength plan proposal : current status Dear Colleagues, Attached please find the intermediate report on wavelength plan proposal, which is based on local discussion in Japan. In addition, I received study results from Dr. Joao Miguel Santos of Siemens and discussed the filter configuration issues. I appreciate his contribution. I would like to elaborate the wavelength plan from the proposal in the slides, and it would be appreciated if you could give me any comments and technical proposals. I wish to apologize in advance for the inconvenience that I will be out of my office from May 2 to 8. Through the study, I recognize the difficulty of deciding the downstream wavelength. The situation of broadband services and its access technologies varies widely depending on countries and operators. Some operators may not care the coexistence among 1G-, 10G-EPON, and RF-video. As a solution to resolve the problem, is it possible to specify two wavelenth band for downstream? For example, Option-1: 1480-1500 for greenfield deployment, Option-2: 1574-1580 for the coexistence among 1G-, 10G-EPON and RF-video. I hope that the concept of creating options is acceptable. Best regards, Keiji Tanaka
Intermediate report(070501) v 1.1.ppt