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Hi Dan, I would like expend on your comment that we have a jam-packed agenda. Not only do we have a large quantify of presentations, but we also have great depth and breadth of material in those presentations. Some of the technical results being presented are ground breaking and reflect major efforts. We should take pride in our Study Group for being a venue for reporting such high caliber work.
Let’s take as an example Sudeep’s excellent presentation; bhoja_01_0112. As pointed out by Mark in nowell_01_1111 (page 8 table), PAM-16 has 1 laser instead of four lasers required for LR4. All things being equal that can translate to dramatic long term cost reduction, which Gary reconfirms in nicholl_01_0112. One seductive analogy that comes to mind is 10GE-LR versus 10GE-LX4. However, it is the implementation details that will determine whether this promise is real or an illusion. The problem is that many Study Group participants, including us, have no experience with high order PAM modulation, to enable a quick conclusion. We will need lots more time to digest this material. A great example of why this understanding is critical comes from nowell_01_1111 observing that xA-yDPSK modulation also requires 1 laser instead of 4 lasers. There are published works showing Si implementations, so even the building blocks appear similar to the PAM-16 proposal. Fortunately, many Study Group participants already have multi-year experience with complex modulation and can immediately conclude that this approach is orders of magnitude away from being technically feasible as a low cost, low power client interface. If we want to seriously consider PAM-16, we will need time to study it and understand the real implementation limitations. Mark and Gary have convinced me that this an area worthy of further study, but I do not see how that can be done by next week as urged by Dan. We will need at least two more meeting cycles to reach an independent conclusion if this is real. It is critical for the chair to have a sense of urgency to make forward progress. I fully internalized this during 802.3ba, where without John D’Ambrosia continuously herding the participating cats, it would have taken us a decade to finish. However, that needs to be balanced against allowing sufficient time for proper deliberation. if we want a SMF objective, we have to invest more time, unfortunately with no assurance that we will end up with an SMF objective at the end. My second concern is that we are lumping together two very different applications and technologies into one SMF objective bucket, specifically parallel SMF for 300m to 500m applications and duplex SMF for 1km to 2km applications. A group of us discussed this at lunch during OIF, and Steve Trowbridge made a very insightful observations. In 802.3ba we did not have explicit statements about fiber cabling in either the MMF or SMF objectives, but very strong implications were there. Every participant understood that the MMF objective was for parallel MMF, and the SMF objective was for duplex SMF. Had we moved into Task Force and switched to duplex MMF (let’s say using WDM) or parallel SMF (let’s say because of cost), many in the larger optics community would have felt misled. Looking at parallel SMF, we are reaching a critical mass for Technical Feasibility, among other reasons because there are multiple credible technical solutions on the table. On the other hand, the Broad Market Potential for 300m to 500m parallel SMF standard is questionable. In additional to carving out a small fraction out of a moderate Market, there are many end users that will not even consider parallel SMF for future deployments. This runs counter to solving fiber congestion which is becoming a major problem in IDCs. For duplex SMF, if we assume the potential for dramatic cost reduction versus LR4, like 4x, then Broad Market Potential is more credible. However, we are nowhere near showing Technical Feasibility. Given this disparity, if we are serious about parallel SMF and duplex SMF, each addressing different applications, we need to two separate SMF objectives, where each one stands on its own merit. To move forward with one SMF objective, by using parallel SMF for Technical Feasibility and duplex SMF for Broad Market Potential would be misleading the larger optics community. Moving forward with one SMF objective by using parallel SMF for both Technical Feasibility and Broad Market Potential, and then switching to a duplex SMF solution would be even worse. I look forward to a great meeting next week and wish everyone safe travels.
Chris From: Daniel Dove [mailto:ddove@xxxxxxx] Dear Study Group Members, We have received all of the presentations to be given in Newport Beach and the leadership team is finalizing the agenda shortly. Our vice-chair Kapil Shrikhande will be sending out an email to the reflector later today communicating the link when the website is ready for operation. Our goal is 12pm PST today. As you will see, we have a jam-packed agenda and are planning to work from 8am to 6pm both days. Due to the magnitude of the workload, I will be putting some rules on discussion to ensure fairness and efficiency. We will discuss these at the beginning of the meeting. Your contribution to an efficient flow of work will help us to achieve success. If we can conclude our SG work in Newport Beach, we may find ourselves with less to do in Waikoloa..think about that! :) Best Regards, Dan Dove Chair, Next Generation 100Gb/s Optical Study Group |