Instead of ‘Follow Me’ and ‘Copy along path’, try with c-points (guides)
or… you can also just try to use a material in which with the help of a texture you allow it to be brighter from place to place (instead of having a lot of v-ray light spheres). It is also possible to create those optical fibers as tubes, applying the material with lights on the inner cylinder, and the outer one to be semi-transparent and colored.