- Since the core and cladding have different indices of refraction hence they have different attenuation coefficients α1 and α2
- For step index fiber, the loss for a mode order (v, m) is given by,
… (2.5.1)
For low-order modes, the expression reduced to
… (2.5.2)
where, and are fractional powers.
- For graded index fiber, loss at radial distance is expressed as,
… (2.5.3)
The loss for a given mode is expressed by,
… (2.5.4)
where, P(r) is power density of that model at radial distance r.