Experimental Simulation of a Multiple Beam Optical Waveguide

The possibility of sending a multitude of gaussian light beams down a single lens waveguide has recently been suggested as an inexpensive means of multiplying the capacity of the waveguide.1-2 Though the beams would overlap along the guide, appropriate optics could separate them in the receiver. The density of resolvable beams in the system is determined by beam distortion and scattering rather than the spread of the ideal beams. Smooth imperfections of the optical surfaces cause the beam to deviate from the exact position and distort its profile and cross section.3 This limits the density of the beams and determines the receiver size required to secure reception. Surface irregularities that are small compared with the beam size result in scattering that is collected by receivers of adjacent channels.4 This crosstalk increases with the receiver size, the density of beams, and the number of scattering elements. The purpose of this experiment was to check the amount of distortion, to determine the receiver size required, and then to measure the scattering and find out what beam density and transmission dis* Formerly with Bell Telephone Laboratories at the Crawford Hill Laboratory. Now with the University of Southern California. 1445