Cascaded fiber optic lattice filter

Abstract From the Canadian patent

Abstract A fiber optic lattice filter having a transfer function wherein the poles and zeros are adjustable independently of each other. The filter comprises a cascaded configuration of recursive and non-recursive fiber optic lattice filters. In one preferred embodiment an all-pass fiber optic filter is formed by cascading allpole and all-zero lattice filters, and by processing the resulting filtered output signal in a subtractive detection system. This detection system produces a signal which represents the difference between two signal outputs provided by the all-zero filter section and which is, adjustable in magnitude, thereby providing an overall filtering function which is capable of …