Design of Optical Notch Filters Based on Equivalent Relations

The transfer functions of optical notch filters based on all fiber unbalanced Mach-Zehnder interferometer with fiber ring coupled structure and Michelson Gires–Tournois interferometer structure are presented based on z-transform method respectively. On this basis, the structural parameters between the two kinds of notch filters are revealed to have some certain equivalent relations. With this equivalent relationship, the structural parameters for designing one of the two kinds of notch filter can be conveniently obtained by that of the other of the two kinds of notch filters. A design example of a two notch point notch filter using the method is given in detail in the paper.