[10GMMF] Corrected Monte Carlo Model as LRM standard model for OM1
All,
At the London meeting, several of us made a presentation on the Monte Carlo
set corrected for mode mixing (the gamma correction). I showed duplex
coverage PIE-D results for the recommended correction of gamma = 0.9, and
recommended that this model be used henceforth for LRM coverage
calculations. See
http://grouper.ieee.org/groups/802/3/aq/public/upload/Implicationsofduplexco
veragewithcorrectedMonteCarlomodelforTP3stressors.pdf
At the meeting Jon Abbott and I received useful feedback from Jon King that
sensitivity analysis of the choice of lowest OFL-BW value admitted into
coverage calculations was needed to assess the robustness of the fiber
model. Fiber modeling for LRM typically uses 500MHz-km as the lower cutoff
for OM1 fiber in all calculations to date. Kasyapa Balemarthy (GaTech) has
done this analysis, and it increases the credibility of using the Monte
Carlo model to assess OM1 coverage for LRM.
Kasyapa varied the LOWER limit of OFL-BW fibers retained in the MC model and
found that the 99%tile duplex PIE-D point changes linearly by 0.05dB for
each 50MHz-km change between 400 and 600 MHz-km. This relative
insensitivity arises from the fact that a wide range of both low and high
PIE-D fibers exist in a selected range of OFL-BW, and the distribution of
PIE-D values within a range of OFL values varies smoothly as OFL rises from
400 to 600MHz-km.
This is very good news and means that the MC model is robust to the choice
of this parameter, i.e. coverage results obtained are rather insensitive to
picking 500 MHz-km vs. 475 or 525 MHz-km.
I would like to assess whether there are any remaining technical objections
to using the Monte Carlo model at 1355nm with a gamma=0.90 correction as the
standard model for LRM coverage calculation.
Robert
Robert Lingle, Jr, Manager
Fiber Design and Transmission Simulation
OFS R&D, Atlanta, GA