Normalized frequency (fiber optics)

In an optical fiber, the normalized frequency, V (also called the V number), is given by

V=2πaλn12−n22=2πaλNA,

where a is the core radius, λ is the wavelength in vacuum, n1 is the maximum refractive index of the core, n2 is the refractive index of the homogeneous cladding, and applying the usual definition of the numerical aperture NA.

In multimode operation of an optical fiber having a power-law refractive index profile, the approximate number of bound modes (the mode volume), is given by

V22(gg+2),

where g is the profile parameter, and V is the normalized frequency, which must be greater than 5 for the approximation to be valid.

For a step-index fiber, the mode volume is given by V2/2. For single-mode operation, it is required that V < 2.4048, the first root of the Bessel function J0.

## See also

* Abbe number

## References

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Normalized frequency (fiber optics). Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Engineering:Normalized_frequency_(fiber_optics)&oldid=665411"