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Dear Marco, Thanks for your detailed presentation at last Tuesday SMF adhoc meeting. As agreed I would send you this email to clarify my questions. What was your intent with this presentation, demonstrating that 112G PAM4 can work or that you can establish a solid power budget? If it were the first, I would agree that you succeeded, but if it were the latter, I would have some concerns. From the latter point of view it is a pity that you didn’t include slide 11, first slide of your back-up slides, during the adhoc meeting, because I had intended to raise a further question. This slide, taken from bhatt_3bs_01a_0714, shows a needed Rx sensitivity of about -10dBm. Our experiments (details in stassar_3bs_01_0714 in San Diego and song_3bs_01a_0514 to Norfolk) showed a receiver sensitivity
of -6.7 dBm, which is more than 3 dB “short” of your suggested specification. Would you be in a position (now or soon) to confirm a sensitivity of -10dBm by experiments? We would be very interesting to see the receiver sensitivity results of other organizations. The presentation bhatt_3bs_01a_0714 was presented during the San Diego meeting. After this presentation many concerns were voiced and it be difficult to repeat all here. One specific question from myself was related to the proposal towards a CWDM configuration, specifically about chromatic dispersion penalty testing at the highest envisioned wavelength, being 1338nm. At this
maximum CWDM wavelength the maximum dispersion will be 6.8ps/nm, which is relatively higher than the 100GBASE-LR4 spec of +10ps/nm, so probably we will not be able to ignore the associated penalty, even for 2km SMF. In a similar way as to your presentation
I asked Vipul how to derive the suggested receiver sensitivity from the test results. In my presentation in San Diego, stassar_3bs_01_0714, I expressed that closing a power budget for a 4x112G PAM4 configuration for 2km, is very, very challenging, with either very stringent transmitter power requirements
or very stringent receiver sensitivity requirements. We have made this analysis after extensive optical testing a complete optical link including transmitter and receiver. In the end of the presentation other parties are invited to confirm our assessments
or show improved data. Thanks in advance for the further information. Kind regards, ciao, Peter Peter Stassar, 施笪安
Technical Director, 技术总监
Huawei Technologies Ltd,
华为技术有限公司 European Research Center,
欧洲研究所 Karspeldreef 4, 1101CJ Amsterdam The Netherlands Tel: +31 20 4300 832 Mob: +31 6 21146286 |