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Re: [802.3_100GNGOPTX] questions remained unanswered at the Q&A session at 802,3bm Plenary after the presentation of welch_01_0313_optx

Thanks Dan.
The baseline proposal was presented in Phoenix here

The draft spec will be along the line of the baseline proposal. I will work with the rest of the team to fix as much as possible and minimize TBDs.
I would encourage the rest of the team memers that are not already part of the consensus team to send me private email if they want to join or have suggestions or concerns regarding the draft.

Date: Mon, 25 Mar 2013 17:07:37 -0700
From: dan.dove@xxxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GNGOPTX] questions remained unanswered at the Q&A session at 802,3bm Plenary after the presentation of welch_01_0313_optx
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx

Hi Arash,

Thanks for communicating that.

Be sure to bring along a baseline proposal that includes all key elements of the draft document so people can decide upon it. I expect to see TBDs on some parameters in the draft that are soft/fuzzy, but all critical parameters/functionality should be defined and proven through your proposal.


On 3/25/13 4:59 PM, Arash Farhood wrote:
Hi Dan and the team,
  As stated in BM meeting, I volunteered myself to provide the PAM draft. In the PAM consensus team we believe a serial scheme is the right option. I will work with the rest of the team to produce the right draft.


Sent from my iPhone

On Mar 25, 2013, at 12:13 PM, "Daniel Dove" <ddove@xxxxxxx> wrote:

Hi Ali,

Thank you for sharing your opinion.

The Task Force chose to move forward with a draft development for both a PSM4 (Pete) and CWDM (Petar) doing the work, on the assumption that one of these approaches *may* see sufficient consensus to achieve a baseline proposal adoption. PSM4 was highest in the straw polling, and CWDM was next highest.

Anyone who has confidence that they can achieve consensus on an alternative baseline proposal is asked to also produce a draft clause so that we can leave the May meeting with a full draft set of clauses to move forward with into Task Force review.

Clearly, LR4 and ER4 will be choices available to the industry in a 4x25 CAUI-4 based solution. Whether or not they are sufficient to address broad market needs over time will be defined by the Task Force.


Dan Dove
Chair, IEEE P802.3bm
On 3/25/13 11:39 AM, Ali Ghiasi wrote:
Dear Dan

We had a very productive OFC meeting and hope you as well had a productive IEEE meeting!

There were two interesting announcement at OFC with implication to .bm SMF objective:
Where Finisar CFP2 100Gbase-LR4 PD< 7 W based on DFB DML

Where Cisco announces 100Gbase-LR4 CPAK OFC demo based on Silicon Photonics with PD < 5.5 W

Above 100GBase-LR4 products in live demo during OFC-2013 have power dissipation lower than power quoted in some of the IEEE presentations.

PSM4 does not offer cost advantage of 0.23-0.13 as was illustrated with PAM solution 

It is clear that in the .bm group the solution based on serial 100 Gb/s with best economic and cost advantage require more time to converge to a baseline proposal than we have in the bm group.  IEEE already has the Cadillac solution the 100Gbase-LR4 and I believe nearly everyone in our task  force would agree the ultimate solution is serial 100 Gb/s and something we have to define in the 400 GbE, but we may disagree on the timing.  If we can't agree to define the ultimate solution now, do we wait or do we define something between the Cadillac and the ultimate solution that may only have short term market potential ?  

I would definitely support both CWDM and PSM4 as part of an MSA definition.


On Mar 25, 2013, at 10:16 AM, Daniel Dove wrote:

Hi Brad,

Thanks for bringing this up.

All, when producing questions on a presentation please be attentive to the fact that we participate on an individual basis and frame your questions to the individual, not their employer or affiliation.

In the same manner, if someone asks you a question directed to your employer or it's business, or any other business for which you may have information that is proprietary, do not feel obligated to respond.


Dan Dove
Chair, IEEE P802.3bm

On 3/25/13 9:57 AM, Brad Booth wrote:

I’m a bit concerned about this line of questioning and some of what I noticed happening at last week’s meeting (at least the portion I was able to attend).


There seems to be a lot of focus on vendor-specific implementations which then trends into the realm of cost comparison, NDAs,  and opinions on technical viability.


The goal of the task force is to develop a standard written such that it is not dependent on any implementations, but rather that it enables multiple, interoperable, compliant implementations.


Is it possible to put the relative cost comparison and vendor-specific implementation information aside and focus on the market requirements and technical merits of each proposal?





From: Yurii Vlasov [mailto:yvlasov@xxxxxxxxxx]
Sent: Thursday, March 21, 2013 5:11 PM
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: [802.3_100GNGOPTX] questions remained unanswered at the Q&A session at 802,3bm Plenary after the presentation of welch_01_0313_optx


Dear all,

As a follow-up on yesterday’s discussion I am summarizing here questions to the presentation
Some of the questions I was able to ask during the Q&A time, while some of them were left unanswered or even not asked due to request of the Chair to move the rest of the discussion offline. Following Chair’s suggestion I am writing down all the questions I was planning to ask here in the Reflector. I do believe that it is important for people on the floor to get an unbiased view on advantages and disadvantages of various proposals as well as on technologies behind them to cast a balanced educated vote.
The answer on the first question is crucial. I would have had no further questions if the answer would have been “Yes”. However the answer was “No”. Correspondingly I feel obligated to present here all the questions numbered consecutively with the page number in the presentation listed for the reference.

Page 1
Question 1
Do you agree or do you not, “yes” or “no” would suffice, that “Si Photonics” in the title of your presentation means “Luxtera Si Photonics technology” and, correspondingly, the numbers and statements presented are related to advantages and disadvantages that Luxtera technology has in trying to reach performance required by different baseline proposals?

Page 2
Question 2
This page represents the strategy for comparative analysis of link budget, power, assembly and cost for CWDM, PSM4 and LR4. Depending on how this strategy is formulated a substantially different set of conclusions can be reached.
It is stated that for power estimate the “fully integrated silicon photonics solution using 28nm CMOS node” is being used. Does “full integration” means CMOS circuits and optical devices located side-by-side on the same silicon die?

Question 3
What is the level of maturity of this “fully integrated silicon photonics 28nm CMOS technology” – a) is it in development, b) is it fully qualified or, by any chance, c) does Luxtera already have transceiver (not AOC) products shipped today in volumes with this technology node?

Question 4
In this page you mention “existing silicon photonics technologies”. Which existing silicon photonics technologies are you considering: a) Luxtera technology exercised in 130nm node at Freescale, b) Luxtera 28nm technology mentioned above, c) any other Luxtera technology not mentioned or d) Si Photonics technologies of other companies?

Question 5
If the answer to Q4 is “all of the above”, what are the sources of your information and what is the approach you are using in assessing the non-Luxtera Si Photonics technologies?

Page 4
Question 6
Which technology version of Luxtera Si Photonics technology the performance numbers of WDM mux and Demux correspond to – a) the 130nm Freescale or b) “fully integrated silicon photonics 28nm CMOS node”?

Question 7
How different is the interleaver presented on the right bottom corner of this page from the one reported in T.Pinquet et al, Proc. of SPIE Vol. 6898, 689805, (2008) with 2.6dB insertion loss?

Question 8
Are you aware of other reports on low-loss and passive (no tuning power required) WDM filters demonstrated in a number of non-Luxtera Si Photonics technologies?

Question 9
For example, are you aware of several presentations presented in the past at this IEEE 802.3bm as well as in the 100G Study Group meetings on WDM filters based on non-Luxtera Si Photonics technologies that have less than 3dB insertion loss:
pages 9 and 10 in gill_01b_1112_optx.pdf
page 12 in vlasov_01a_1112_optx.pdf
page 6 in martin_01_0712_optx.pdf
page 4 in vlasov_01_0312_NG100GOPTX.pdf ?

Question 10
Are you aware that of these WDM devices listed in Q9 (in addition to many other silicon photonics WDM demonstrations currently in the public domain) NONE are relying on active thermal tuning of the WDM components phase and hence do not contribute to the total dissipated power as it is demonstrated, for example, on page 10 of gill_01b_1112_optx.pdf ?

Question 11
Are you aware that all of these measured results listed in Q9 are obtained on chips fabricated on a high-volume non-Luxtera Si Photonics technology platforms in Kotura or IBM?

Question 12
 Do you agree that the necessity to burn a total of 1.8W of power for tuning of WDM components as suggested in page 4 is not a generic problem with all Si Photonics technologies, but rather, perhaps, a problem with one of Luxtera’s Si Photonics technologies? Which one?

Page 5
Question 13
Does the “PSM4”, “CWDM” and “LR4” on the top of each column have any relation to corresponding baseline proposals as it was presented at the latest meetings of 802.3bm (anderson_01a_0313_optx.pdf and vlasov_01a_0313_optx.pdf,)?

Question 14
The usual approach to calculate the optical power link budget that 802.3 has followed for many years is to calculate the channel insertion loss between TP2 and TP3 and add the TDP penalty. For all IEEE standards this link budget does not include insertion loss of the transmitter or receiver. These latter numbers are left for vendors to resolve and are not a part of any standard.
If the Q13 answer is “yes” then do you agree that the link budget calculations should follow the usual definition as channel insertion loss plus TDP penalty for 500m channel reach as presented for all PMD baseline proposals so far?

Question 15
If the answer to Q13 is “yes” and the “CWDM” column represent an attempt to build a channel insertion loss budget based on the 100GBASE-CWDM baseline proposal (vlasov_01_0113_optx  or vlasov_01a_0313_optx) , why 2km option is used on line 4 with additional 0.75dB insertion loss, while the objective of both the 802.3bm TF and the baseline CWDM proposal is the reach up to 500m?

Question 16
If the answer to Q13 is “no” this means that columns “CWDM” does not refer to a specific baseline proposal. It is possible then to assume that the table represents an attempt to fold module insertion loss into the link budget and compare to other solutions.
 In this case, if the answer to Q4 is “all of the above” and the answer to Q9 is “Yes” then why additional 3dB+3dB=6dB insertion loss due to MUX and DMUX is included for “CWDM” column since it is a problem specific only to one or all of Luxtera technologies in yielding low loss WDM, and this generalization is not applicable to all possible non-Luxtera Si Photonics technologies?

Page 6
Question 17
If the answer to Q13 is “yes” and columns “PSM4” and “CWDM” correspond to PSM4 and CWDM baseline proposals as presented in anderson_01a_0313_optx.pdf and vlasov_01a_0313_optx.pdf, correspondingly, then the bottom line of the table representing “per baseline proposal (aggregate)” corresponds to maximum channel insertion loss. Correspondingly, for the baseline PSM4 this should be 3.26dB and for the baseline CWDM should be 4dB. Correspondingly, the difference in channel insertion loss between PSM4 and CWDM baseline proposals should be 0.74dB, not 7dB. With maximum TDP budgeted differently (for baseline PSM4 as 3.8dB and for baseline CWDM as 2.2dB) the total power link budget for maximum TDP is actually 7.06dB for PSM4 and 6.2dB for CWDM. Do you agree?

Page 8
Question 18
If the answer to Q1 is “Yes” there are no comments related to pages 8, 9, 10, and 11 since it solely represents numbers for Luxtera “fully integrated silicon photonics solution using 28nm (or better) CMOS node.” The maturity level of this technology is already answered in Q3. If the answer to Q1 is “No” – then there is a question: Which version of non-Luxtera Si Photonics technology (and from which company) is used to fill out the columns “CWDM” and “LR4” in pages 8, 9, 10, and 11?

Page 12
Question 19
There is a subnote “Achilles heel of CWDM”. Which non-Luxtera Si Photonics technologies are having these problems?

Page 13
Question 20
Which non-Luxtera Si Photonics technologies are having these problems?
For example edge coupling technologies are, in fact, widely used for edge emitting lasers iii-V PICs, etc. for many decades. Some of non-Luxtera Si-Photonics technologies successfully using edge coupling for volume products, like for example VOA and other components from Kotura. It is, actually, vertical grating couplers that Luxtera technology is using that is a relatively new and to my knowledge unique approach for coupling light in and out of the PIC.
In general, it is possible to imagine that non-Luxtera Si Photonics technologies utilizing edge coupling might not necessarily suffer from violation of CMOS design rules, do not require CMOS post-processing (precision dice/polish), can enable easy fiber attach, and do not require large area for bonding to CMOS.

Question 21
If Luxtera Si Photonics technologies are being used for comparison it would be good to know which version of the technology a) 130nm Freescale or b) “fully integrated silicon photonics solution using 28nm (or better) CMOS node” is being considered?
If it is a) then indeed millions of parts were shipped and edge coupling was not in production and is only theoretically known. If it is b) then it is necessary to refer to the answer to Q3 and apply it here with respect to the statement “millions of grating couplers already shipped”.

Question 22
What the source of the information that non-Luxtera Si Photonics technologies using edge coupling are having a problem of “prohibiting chip on board cost reductions”.?

Question 23
What the source of this information that non-Luxtera Si Photonics technologies that are using edge coupling are having to rely on “polarization maintaining fiber”?

Page 14
Question 24
If the answer to Q1 is “No” and the statements on this page also include comments on non-Luxtera Si Photonics technologies, then the word “theoretically” should be removed since numerous feasibility demonstrations have been presented in the open public domain showing monolithically integrated WDM mux, Demux, photodetectors, modulators, etc. that can be found for example in the proceedings of the OFC from 2007 to 2013. I can easily provide over 50 recent references upon request.

Page 15
Question 25
If the answer to Q1 is “No” and the statement on this page 14 “Insufficient technology maturity to reasonably project costs/yields” also includes comments on non-Luxtera Si Photonics technologies, then I would insist on rephrasing the statement to “Insufficient information that Luxtera has on technology maturity to reasonably project costs/yields”.

Page 16
It is a critical page in the presentation as it compares module costs for various implementations.

Question 26
If the answer to Q1 is “Yes” then don’t the statements in this comparison refer to problems specific to Luxtera Si Photonics technologies, and as such this comparison illustrates that Luxtera Si Photonics technologies could not provide CWDM modules in a cost-effective manner.

Question 27
If the answer to Q1 is “No” then the statements in this comparison implies generalization of problems specific to Luxtera technologies to all other non-Luxtera Si Photonics technologies. In this case I would ask which non-Luxtera technology is used for this comparison and what the source of this information is. I would also suggest to take into account three independent relative cost analysis studies presented in martin_02_0912_optx.pdf, shen_01a_0313_smf and in vlasov_01a_1112_optx.

Page 17
Statements on this page either refer to Luxtera Si Photonics Technologies (if the answer to Q1 is “Yes”) or (if the answer to Q1 is “No”) it is required to provide additional information as mentioned in all related questions above.

Sincerely yours

Yurii Vlasov

Dan Dove
Principal Engineer
Dove Networking Solutions
530-906-3683 - Mobile