Refracting rays graded-profile fibers

The refracting-ray transmission coefficient for skew rays on graded-profile fibers is given by Eq. (7-6) within the local plane-wave approximation, except that 0, = njl — a, where a is the angle between the incident, reflected or transmitted rays and the normal at the interface. We deduce from Eqs. (2-14), (2-16) and (2-17) that... 

The transmission coefficients of Eqs. (7-15) and (7-19) apply to all tunneling rays on graded- and step-profile fibers, except in the limit where a tunneling ray becomes a refracting ray, i.e. when - p. In this limit, the value of the transmission coefficient is relatively large compared to its value for tunneling rays close to the bound-ray limit, i.e. when - oo. Consequently, for certain... 

FigMre 21. 22 Graded-index optical-fiber design, (a) Fiber cross section, (b) Fiber radial index of refraction profile, (c) Input Ught pulse, (d) Internal reflection of a light ray. (e) Output light pulse. 

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