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The proposal to adopt 4x100G PSM4 for 500m, 4x100 WDM for 2km, and 8x50 WDM for 10km will result in three very different PMDs. The similarity between 4x100G
PSM4 and 4x100G WDM is superficial, and stops at wavelength count. All the optical specification which actually define an optical interface are substantially different. WDM is not converted from PSM4; it is a separate development.
The number one determinant of cost is volume. The number two determinant of cost is manufacturing margin. The number of wavelengths has never been an absolute
determinant of cost. For mature technology fewer wavelengths is lower cost. For a new technology rate, the higher speed always has significantly higher cost. 4x100G WDM will be the highest cost solution, once components are available to make it manufacturable,
which is several years away. There is not a single precedent to support the claim that a new technology rate at introduction is lowest cost. This was certainly not true for either 10G or 25G.
Further, by adopting 3 very different PMDs will splinter limited industry R&D resources into developing 2 very expensive new technologies (50GBaud) and 1 derivative
technology (25GBaud) for 3 modest volume applications. Today, the industry is struggling to find sufficient R&D resources to reduce the cost of 10G and 25G optics which will continue to be the dominant volume interfaces for many years to come. The main industry
focus has to remain on 10G and 25G.
From: Brad Booth [mailto:bbooth@xxxxxxxx]
Actually, I prefer the 4x100G lambda solution for 2 kms. If one assumes the 8x50G lambda solution is the preferred proposal for the 10 km reach, I can understand the logic applied to see the 2 km reach version as a reach optimized solution
for that market space. But, if I look at the 2 km reach as it's own market where the maximum reach is 2 km on a duplex fiber, then it seems to me that this technology should more closely resemble the 500 m reach solution. If a 4x100G PSM4 solution is the preferred
proposal in that space, converting that solution from PSM4 to WDM would be preferred. While there is added complexity to convert a PSM4 solution to a WDM solution, I believe that the industry would be able to capitalize on the 500 m reach volume to help drive
down the cost of the 2 km WDM version. One of the other reasons I favor having a 4x100G lambda solution for 2 km is that the task force easily means the distinct identity requirement for each reach solution. The 500 m, the 2 km and the 10 km are all unique and distinct.
Thanks, On Mon, May 18, 2015 at 7:55 AM, Dan Dove <dan.dove@xxxxxxxxxxxxxxxxxx> wrote: Hi Jeff, Dan Dove On 5/18/15 10:04 AM, Jeffery Maki wrote:
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