Hillo Amanda Holt
I've been working a lot with MEEP, for
FBG Design and I could answer.
You should note the following:
1- you can use plano source (size of source = size of FBG core).like this code:
(set! sources(list
(make source
(src (make gaussian-src(frequency fcen) (fwidth df)))
(component Ez)
(center (+ lpml (/ sx -2))wvg-ycen)
(size 0 w) )))
2-For FBG design you should have a good study. As specified Bragg wavelength
and grating pitch (please study this book:FIBER BRAGG GRATING
3- For transmitted flux you can use this code: (center (- (/ sx 2) padx lpml)
wvg-ycen) (size 0 (* 2 w)) )))
4- For reflected flux you can this code: (center (+ (* -0.5 sx) padx lpml) wvg
lpml) wvg-ycen) (size 0 (* 2 w))
I Hope
I have given the right answer to your questions.
E.Amiri, PhD., St., IUT., IRAN
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Today's Topics:
1. Bragg fibers, transmission (Amanda Holt)
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Message: 1
Date: Mon, 9 Dec 2013 16:07:29 -0800
From: Amanda Holt <alh...@physics.upenn.edu>
To: meep-discuss@ab-initio.mit.edu
Subject: [Meep-discuss] Bragg fibers, transmission
Message-ID: <8f942ac6-2327-4b04-b8ac-9ff4b221d...@physics.upenn.edu>
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Hi all,
I am using meep to calculate the wavelength/frequency dependent transmission or
loss down a hollow core Bragg fiber (as described in the online book Photonic
crystals: molding the flow of light). I have been able to replicate all figures
in the book using cylindrical coordinates. Now, I want to calculate the
transmission down a fiber - specifically one with low refractive index contrast
(1.33 vs. 1.55) and low number of crystal repeat units (< 7). I calculate the
transmission using two flux planes - one closer to the source normalized by one
farther away down the fiber. I currently do not consider that the materials
absorb because I want to first examine radiating loss from the photonic crystal
structure. I am trying to get to a point where I can adjust the refractive
indices and the photonic crystal dimensions to compare fiber transmission/loss
for the different scenarios. We are interested in visible wavelengths which and
the frequency range accordingly. The current paramet
ers in the attached ctl file should guide approximately 600 nm light (f=1.67
meep units where a = 1 micron).
As I understand it, I should place the first flux plane far enough away from
the
source to consider primarily guided frequencies. I see large differences in
the
transmission (and sometimes greater than 1) when I change things like the flux
plane position from source and size as well as whether the source is a point or
a plane. I have attempted to optimize the pml layer thickness and the
resolution. My current questions are: 1. Am I modeling transmission down a
bragg fiber correctly? 2. Should I use a point or plane source? 3. How far
from the source should I put the first flux plane such that I primarily look at
guided frequencies? I am currently looking at 2 microns from the source which
is
more than 2X the guided wavelength. 4. Should the flux planes be the size of
the "hollow core", the full fiber or larger?
Thanks in advance for your advice,
Amanda
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Amanda Holt, Ph.D. | Postdoctoral Scholar
University of Pennsylvania, Philadelphia
Department of Physics and Astronomy
alh...@physics.upenn.edu | 831.359.9822
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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