Why in optic fibers, only certain wavelengths (such as 1300,1550) are
used?
Answer
Scattering and absorption are the two
enemies of optic fiber.
When wavelengh increases, scattering is
reduces. That is why they select higher wavelengths ie. 850nm and above
But above 850, why they have not
chosen 1000,1100,1200,etc. Why they
straight away chosen 1300?
Because, fiber has minute amounts of water vapour which absorbs certain
specific ranges of wavelengths called as WATER BANDS. so we hve to choose
wavelengths NOT falling in this range.
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