The Capacity of Multiple Beam Waveguides and Optical Delay Lines

A Fabry-Perot interferometer with curved mirrors can he used as an optical delay line by inserting a laser beam through a small center hole in one mirror. 1 The beam performs many off-axis round trips before leaving the interferometer through the entrance hole.2 Reference 1 suggests t h a t the injection and retrieval of the beam could be improved by mismatching beam and cavity. A systematic study is carried out here to find the longest folded path that starts and ends in the center hole, thus optimizing the system for maximum storage capacity. Very similar to this problem is the analysis of a periodic lens guide in which many beams are to be transmitted in such a way that they are clearly resolvable at the receiver end. One such system is a transmission link that forms an image array of modulators in the receiver plane. The possible density of channels is given by the number of resolvable spots in this plane. 3 The investigation of all possible Gaussian beams transmitted simultaneously in a guide will show that this is only one among many possible systems. All these systems exhibit the maximum theoretical 2095