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My first question for this forum is... when a wave goes through a
waveguide, what is the effective length of the guide. Is it just the
physical length?
My second question is... it is my understanding that an optical fiber
is constructed so the refractive index is continuously graded from a
higher refractive index at the center to a lower refractive index
near the outside.
If this is true, what does it mean to refer to a
cable as having a particular refractive index?
Putting my first two questions together, my third question becomes...
is this apparatus a fraud?
Has the company simply said the
refractive index of the fiber is 1.50 so the calculation ...
comes out correct?
That is, might we say n = 1.50 is an effective
refractive index that we determine from knowing c, rather than
vice-versa?
In a real sense *any* experiment that purports to actually measure c
is a 'fraud'. This is simply because c is a defined quantity--not a
measurable one.
My understanding is that th fiber does work like a wave guide. I
suspect this is true if the relative dimensions are the same.
The chase: the formula for the group speed down the guide is v sub g
= C sqrt[ 1- (frees space wavelength/2*waveguide dimension)^2]; the
wave guide dimension is for a rectangular guide with E perpendicular
(lowest mode).