Talk:Normalized frequency (fiber optics)

Definition:V- number or cut off frequency or normalized frequency is a parameter in optical fibers which determines the number of modes of a step-index fiber.It is defined as: V=(2πa/ʎ)*n1*(√2∆).

Significance of v number: If V is less than 2.405 then the fiber is mono mode but if V is greater than 2.405 then fiber is multimode. V number is also related with the number of modes in the fiber as:

N=V^2/2 for step index fiber and

N=V^2/4 for graded index.