Optical Fiber Communications 4th Edition by Gerd Keiser

Exercise 10

Consider a fiber with a 25- m core radius, a core index n 1 = 1.48, and = 0.01.
( a ) If = 1320 nm, what is the value of V and how many modes propagate in the fiber
( b ) What percent of the optical power flows in the cladding
( c ) If the core-cladding difference is reduced to = 0.003, how many modes does the fiber support and what fraction of the optical power flows in the cladding