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Pete, Regarding your first question. RS FEC can provide you 3-4dB optical gain,
but depends on the receiver type. In case of APD, which is limited by Shot Noise the coding gain is quite similar
to the electrical SNR. While in PIN, which is limited by the Thermal Noise the coding gain is around half of the
electrical gain (APD gain). Haim. From: Pete Anslow
[mailto:pja@NORTEL.COM] Robert, Thanks for the notes from the Ad-Hoc call. I have comments on
three sections: “It was stated that for a 7% overhead
code, such as RS, a 1.5 dB coding gain would be appropriate for PIN case, but a
3 dB gain for APD case. It was not known how to evaluate the pre-amplified PIN
case. This seems to be a major area requiring clarification.“ Was this for RS (255, 239) as defined in G.709? Upstream or
downstream? If it is for (255, 239) downstream I find this surprising are there measurements to
support this? Secondly, “Assuming a
value of 13 dBm for minimum Psat and subtracting 3 dB to avoid patterning and 2
dB for min/max range would yield a minimum SOA output power of 8 dBm as a
working assumption. ” I don’t think that there is any need to
subtract anything for the min/max range. If +13 dBm is the guaranteed minimum Psat, then
subtracting 3 dB to avoid distortion would give +10 dBm minimum. Surely a min/max range of 2 dB means that the spec for
output power would be +10 dBm min and +12 dBm max? Thirdly, “It was not known
how to evaluate the pre-amplified PIN case. This seems to be a major area
requiring clarification.” There is some information on the slope of the BER vs
power curve for pre-amplified receivers in Supplement 39 to the G-Series Recommendations
clause 9.5.2 which is relevant to the FEC gain that might be expected. This can
be found at: http://www.itu.int/rec/T-REC-G.Sup39/en Regards, Nortel Networks UK Limited, External +44 1279 402540 ESN 742 2540 Fax +44 1279 402543 _____________________________________________ Please find attached the notes from today's call. Please review it carefully and discuss issues on the reflector. If you
wish to volunteer to take action items, please let me know. Otherwise I will
raise issues on the reflector and begin asking people to take action items :-) Robert -----Original Message----- From: Lingle, Jr, Robert (Robert) [mailto:rlingle@OFSOPTICS.COM] Sent: Tuesday, February 06, 2007 5:27 PM To: STDS-802-3-10GEPON@listserv.ieee.org Subject: Re: [8023-10GEPON] [POWER_BUDGET] ad hoc group 2nd meeting Please find attached the file for the call today 2/6 at 7PM EST and 2/7
at 9AM. -----Original Message----- From: Lingle, Jr, Robert (Robert) [mailto:rlingle@OFSOPTICS.COM] Sent: Friday, February 02, 2007 4:37 PM To: STDS-802-3-10GEPON@listserv.ieee.org Subject: Re: [8023-10GEPON] [POWER_BUDGET] ad hoc group 2nd meeting Please find attached the notes for the first Power Budget Ad Hoc
meeting. Please direct any corrections to me. Robert -----Original Message----- From: Lingle, Jr, Robert (Robert) [mailto:rlingle@OFSOPTICS.COM] Sent: Thursday, February 01, 2007 3:09 PM To: STDS-802-3-10GEPON@LISTSERV.IEEE.ORG Subject: [8023-10GEPON] [POWER_BUDGET] ad hoc group 2nd meeting All, I will send the notes from this week's meeting tomorrow 2/2. As discussed in the previous call, the next call(s) will occur on
Tuesday Feb 6 at 7PM EST and Wednesday Feb 7 at 9AM EST. Notes from this week's call as well as agenda for next week will be sent
Friday. Toll-free in US 866-263-8899 Outside US 816-249-6061 Conf. Code 7707985015 Robert Robert Lingle, Jr. Fiber Design and Transmission Simulation OFS Corporate R&D, 404-886-3581 (cell) 770-798-5015 (office) |