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Re: [STDS-802-3-400G] Sept Interim Meeting Material Posted



Hi Brian,

You are touching on a very critical point in analyzing proposals.

The means for achieving a particular architecture will not only affect its technical feasibility, but it will affect cost and potentially power and density.

So assuming a particular (ex: SIP vs DTF) (ex: CMOS IC vs SiGe IC) approach will automatically result in cost/power/density implications.

And approving a particular architecture, should convey that there are multiple approaches that meet all criteria. If you can only build a solution one way to achieve all those points, its not an architecture, its an implementation. This doesn't mean that we should mandate multiple means of implementation, but at least a broad industry capability to deliver the architecture whether via a single means, or multiple means.

Thanks for providing the basis for making this point.

Dan Dove
Chief Consultant
Dove Networking Solutions
530-906-3683 - Mobile
On 9/17/14 10:44 AM, Brian Welch wrote:

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

 

 

From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Wednesday, September 17, 2014 10:30 AM
To: Brian Welch; STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: RE: Sept Interim Meeting Material Posted

 

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

 

From: Brian Welch [mailto:bwelch@xxxxxxxxxxx]
Sent: Wednesday, September 17, 2014 9:16 AM
To: Chris Cole; STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: RE: Sept Interim Meeting Material Posted

 

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

 

From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Wednesday, September 17, 2014 9:05 AM
To: Brian Welch; STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: RE: Sept Interim Meeting Material Posted

 

Brian

 

What is your proposal?

 

Chris

 

From: Brian Welch [mailto:bwelch@xxxxxxxxxxx]
Sent: Wednesday, September 17, 2014 9:01 AM
To: Chris Cole; STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: RE: Sept Interim Meeting Material Posted

 

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

 

From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Tuesday, September 16, 2014 4:15 PM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: [PossibleSpam] Re: [STDS-802-3-400G] Sept Interim Meeting Material Posted

 

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