The potential of fiber-optic delay line signal processing has been generally recognized1 and is due to the low loss and large bandwidth (and the ensuing large time-bandwidth product) of single-mode optical fibers as well as its low weight, small size, etc. However, to utilize more efficiently this potential a combination with integrated optics (such as electrooptic LiNbO3 devices) Is essential, since this gives a degree of programmability of delay time, tap weights, etc. for the optical domain processing. Fiber-optic signal processors demonstrated to date seem, however, to be limited to delay lines and delay line filters with fixed or mechanically variable characteristics, limiting the usefulness of the devices.
© 1987 Optical Society of AmericaPDF Article