Using mode theory, we calculate the crosstalk between overmoded optical fibers or light pipes when one fiber is illuminated by a focused collimated beam. The presence of many modes allows the summation of crosstalk power between individual modes to be converted to an integral expression. The result is applied to two parallel, identical fibers, a hexagonal array of fibers, lossy fibers, and fibers of unequal diameter. In practice, the light pipes must be nearly identical and touching for significant crosstalk.
© 1976 Optical Society of America
Allan W. Snyder and Peter McIntyre, "Crosstalk between light pipes," J. Opt. Soc. Am. 66, 877-882 (1976)