Solutions to the synthesis problem of optical delay line filters.

We report new design methods for the synthesis of incoherent low-pass fiber-optic delay line filters with finite impulse responses. These structures are considerably simpler in their operation than infinite impulse response filters, are always stable, and are capable of performing almost the same signal-processing operations. Some of their implementations and applications as adaptive filters or for demultiplexing of high-definition television signals are presented and discussed.