%0 Electronic Article %A M.J. Adams %A D.N. Payne %A F.M.E. Sladen %K transit times %K graded index optical fibres %K guided rays %K tunnelling rays %X Calculations are presented of the transit times of guided and tunnelling rays in graded-index optical fibres. It is shown that 25% of the power launched by an incoherent source into a parabolic-index fibre is carried by leaky rays, which may increase the r.m.s. width of the impulse response by up to 41%. The profile which most effectively equalises the combined transit times of both guided and tunnelling rays is given by α=2−4δ %@ 0013-5194 %T Mode transit times in near-parabolic-index optical fibres %B Electronics Letters %D August 1975 %V 11 %N 16 %P 389-391 %I Institution of Engineering and Technology %U https://digital-library.theiet.org/;jsessionid=7ccbe5oambgk.x-iet-live-01content/journals/10.1049/el_19750295 %G EN