Question

The cladding in a typical multimode cylindrical fiber is only 35 um thick, and yet in analysis of wave propagation of fibers it is assumed to be infinitely thick. Assuming this is permissible only so long as the evanescent wave has attenuated 10 dB at the outer cladding boundary, how long can the wavelength of 89'incident light get before this condition is violated, assuming n an approximate answer by assuming a planar geometry as shown. 1.5 and ng is one percent lower. Get Cladding E250, Ho. Core Erzo. Ho 890