Chris,
Thanks for
sending. Is there cost modeling done using the technique on
page 20? Are there losses for that structure? I see a chart
on slide 21 that seems to suggest the OMAs are somewhere
between -10 to -20 dBm…. Is there more info on this?
How do the
driver/receive I/Cs figure into it? Would be good to see how
a whole module could come together using this approach.
I don’t believe
the alternate integrative approaches shown in 802.3bm, at
least those that were shown consistently, are representative
of solutions that can be effectively deployed in volume.
Many of them made no mention of how coupling/assembly was
performed, variability/control over process and temperature
corners, or how polarization diversity was accommodated on
the receiver.
Thanks,
Brian
Hi Brian,
You make good
points that we have seen proposals and measurements with
high grade components, such as used for long haul telecom
applications. The high cost and power is then dismissed as
not representative of integrated implementations, without
detailed discussion of what the implementations actually
are.
We do need to
be cautious about using your approach to benchmark
implementations. The SiP PIC grating coupler which you have
presented is bandwidth limited so obviously has high loss
for WDM applications. However, there are other approaches,
including for SiP PIC like some presented in .bm, which do
not have this limitation.
So I agree with you that if when you present your technology
it is not appropriate to use the proposed lower Mux/DeMux
loss numbers. However, we will keep in mind that it’s not
good approach to WDM.
With respect to
your beliefs, I hate to shake them, but here is at least one
real example of 8x50G integrated solution:
http://www.ieee802.org/3/bs/public/14_07/cole_3bs_01a_0714.pdf#page=20
Chris
My proposal is
not to assume very low loss technologies for technical
feasibility, while simultaneously assuming that future
integration will bring the cost down. I’ve heard many times
on questioning that products will be cost reduced in the
future with ‘Integration and SiP’, although no presentations
as to whether these proposals would allow for such measures.
As per what I
think are likely losses for WDM MUX/DEMUX I’ll refer you to
my prior bm and bs presentations on the matter, at least for
2L and 4L. I don’t have anything on 8L as I don’t believe
such solutions will ever allow for integrated solutions,
although I may be able to provide more quantitative answers
in our next meeting.
Brian
Brian
What is your
proposal?
Chris
What
technologies/integration are you assuming in these MUX/DEMUX
figures? Conservative for one technology (ie, discrete thin
film) may not be for another (ie, integrated SiP).
Brian
Dear Task Force
Participants,
Last week, the
TF gave permission to update cole_3bs_02 to include TX and
RX analog BW used in TDP calculations, which was requested
during Q&A. The updated deck was posted last week.
http://www.ieee802.org/3/bs/public/14_09/cole_3bs_02b_0914.pdf#page=5
(pages 5 and 6)
On a separate
topic, in this presentation, we use 2.5dB for 4:1 WDM Mux
and 1:4 WDM DeMux loss, which is conservative. Other
presentations use loss values of 1.5dB and 2.0dB. Since
these values do not enter into normative specifications,
normally there is no need for agreement. However, when
making comparisons between different approaches, if the loss
values are not the same, the results are not
apples-to-apples.
To enable fair
comparison of different results I would like to propose that
we all use 2.0dB as the value for 4:1 Mux loss, and for 1:4
DeMux loss. This value was used by Alan Tipper in his
analysis. This is neither conservative nor aggressive. Using
this number in no way constrains implementations. When we
adopt normative specifications, everyone is free to set
their design and production targets as they please.
If we can agree
on a consensus 4:1 Mux and DeMux loss value for use in
analysis, I will update our optical specifications analysis
to reflect it.
Thank you
Chris