Re: [8023-10GEPON] Meeting Report (April 13th in Japan)
Dear Robert,
* Rx Sensitivity
I just gave end-point's Rx sensitivities at ONU and OLT because
they are the value we have to decide in the standard.
The vendors in Japan also considered WDM filter insertion loss
(US/DS/Video), crosstalk and other margins and reflected them
to the proposal. But since they differ among the vendors in the
idea of loss/margin estimation, they were not explicit in this
proposal.
Please refer to my presentation in Orlando. It described the
range of the values proposed from the Japanese vendors.
* FEC gain
We basically assumed RS(255,239) and most of the vendors estimated
the coding gain as 3-4dB for APD-Rx.
Some of the vendors refered to Enhanced-FEC but it was not included
in the proposal this time.
* Sensitivity difference
We assumed comparatively cheap DFB lasers for US although adoption
of EML seems to be necessary for DS to overcome fiber dispersion.
In the case of Direct Modulation Laser, we have to use it with
lower ER to guarantee high-speed operation and it will lead to an
additional penalty. And also Relaxation Oscillation Frequency
(Resonance Frequency) inherent in DFBs will induce waveform distortion
and it will end up performance degradation.
Overall, we estimated 2dB deterioration for APD sensitivity as
compared with one of EML.
The presentation on EML@ONU attached to the previous report suggested
the advantage of the use of EML for this reason to easily reach 29dB.
Best Regards,
Motoyuki Takizawa
On Mon, 23 Apr 2007 23:02:26 -0400
"Lingle, Jr, Robert (Robert)" <rlingle@OFSOPTICS.COM> wrote:
> Dear Takizawa-san,
>
> Can you explain what are your assumptions about Rx sensitivity and FEC gain
> in the three cases shown below?
>
> I notice that a better sensitivity is assumed for the the upstream APD (at
> OLT) than for the the downstream APD (at ONU). Why are those different?
>
> Robert
>
> -----Original Message-----
> From: Motoyuki TAKIZAWA [mailto:mtaki@ACCESS.FUJITSU.COM]
> Sent: Tuesday, April 17, 2007 8:47 AM
> To: STDS-802-3-10GEPON@listserv.ieee.org
> Subject: [8023-10GEPON] Meeting Report (April 13th in Japan)
>
>
> All,
>
> In the last Friday's telephone conference, all the six Japanese vendors
> held a meeting and carefully discussed the OLT and ONU parameter details
> considering not only optical component feasibilities and FEC increments
> but all possible optical filter losses, crosstalk penalties, and optical
> source degradeations, since the 29 CHIL requirement is not an easy goal
> for 10G system to achieve.
> After several amendments, all the vendors concluded to suggest the
> following tables as the baseline specs. for the first draft.
>
> - 10G Upstream
> [DFB@ONU, APD@OLT]
> ONU Launch Power(min) +5 dBm
> OLT Sensitivity(max) -25 dBm
> CHIL 29 dB
> Path Penalty 1 dB
> Extinction Ratio 6 dB
>
> - 10G Downstream
> [PIN@ONU] [APD@ONU]
> OLT Launch Power(min) +11 dBm +3 dBm
> ONU Sensitivity(max) -19 dBm -27 dBm
> CHIL 29 dB 29 dB
> Path Penalty 1 dB 1 dB
> Extinction Ratio 9 dB 9 dB
>
> We'd had two discussion materials about PMD component choices, suggesting
> the benefits of APD@ONU and EML@ONU each, shared among attendees
> prior to the conference.
>
> We first went through the material which suggested the benefits of APD,
> or rather, no SOA in OLT. To PIN supporters, cost was still a main problem
> and they still stuck to PIN option.
> After the serious discussion, the preferences of the venders were not
> changed and were clearly deviced into 3:3.
> So each group of supporters will be posting their proposal and
> we will move the discussion to the reflector.
>
> Another material suggesting EML@ONU was also discussed,
> but it seemed that the venders thought DFB would still be preferable.
> Possibility to merge EML specs. into DFB's will be further studied.
>
>
> Best Regards,
> Motoyuki Takizawa
--
Motoyuki Takizawa
Fujitsu Access Ltd. R&D Center