Re: [8023-10GEPON] [POWER-BUDGET] 10G PIN sensitivity at ONU
Dear Hiroshi,
I am left to wonder, then, why the APD sensitivity number is not similarly
reduced? I think we both began with the specifications on practical XFP
optics, which are -18 dBm for PINs and -24 dBm for APDs (that was my idea,
at least).
So, if PINs get degraded to -16 dbm, then shouldn't APDs get degraded to -22
dBm?
Put another way, if we use the numbers put forward from the Japanese
sub-group, we see that the APD - PIN sensitivity difference is 8 dB. This
seems to be a little on the high side. More nominal APD advantage is around
6 dB, especially when you factor in that the APD is probably less than
optimized in the access device.
Sincerely,
Frank E.
-----Original Message-----
From: Hiroshi HAMANO [mailto:hamano.hiroshi@JP.FUJITSU.COM]
Sent: Monday, May 14, 2007 7:10 AM
To: STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON] [POWER-BUDGET] 10G PIN sensitivity at ONU
Dear Dr. Lingle;
Thank you for your E-mail.
I have asked some colleagues, who are involved in XFP design and production,
about its receiver sensitivity. They said that practical XFP receiver
sensitivities are distributed between -18dBm and -19dBm, and they cause
yield issues if you reject receivers with the sensitivity worse than -18dBm.
As additional WDM filter losses and other penalties are significant and
cannot be ignored, related items are listed in the table of 'Vender
Summary',
ONU sensitivity should be considered worse than that of PIN-RX.
Some 1dB may be easily allocated for each WDM filter and penalty, but
piling up those worst-case numbers is destructive in the 29dB CH IL B++
case.
Total loss coordination in the ONU transceiver was therefore admitted as
the vendor's choice to make the sensitivity degradation together as small as
possible (within 1-2dB, I suppose). I am not sure a detailed discussion
about
loss and penalty has been done in each vendor, but I believe, with FEC,
'-19dBm'
is the most likely and marginal number for ONU sensitivity at this moment,
and most of the vendors here have suggested the same.
I appreciate your further questions and comments.
Best regards
Hiroshi Hamano
Fujitsu Labs. Ltd.
%% "Lingle, Jr, Robert (Robert)" <rlingle@OFSOPTICS.COM>
%% [8023-10GEPON] [POWER-BUDGET] 10G PIN sensitivity at ONU
%% Fri, 11 May 2007 10:12:54 -0400
> The effective PIN diode sensitivities assumed in the two draft Downstream
> power budgets on the Reflector (Effenberger 4/18 and Takizawa 4/30) differ
> by 2 dB, when FEC cosnsiderations are eliminated:
>
> Effenberger -22 dBm, including ~4dB of FEC gain, for effective Rx
> sensitivity of -18 dBm.
> Takizawa -19 dBm, including ~3 dB of FEC gain, for effective Rx
sensitivity
> of -16 dBm.
>
> Hamano-san told us that the Takizawa budget does not assume a cheaper PIN
> than Effenberger, but he said that it rather includes penalties inside the
> Rx which must be accounted for.
>
> I would appreciate it if Hamano-san (or some other person familiar with
the
> issue) to describe in some detail the estimates leading to the -16 dBm
> number, so we can try to narrow the gap between these two drafts in this
> area to a common number.
>
> Robert
>
> Robert Lingle, Jr.
> Fiber Design and Transmission Simulation
> OFS Corporate R&D, Atlanta
> 404-886-3581 (cell)
> 770-798-5015 (office)
>
>