Based on the nonlinear phase transmission characteristics of the ring resonator

a novel dynamic spectral filter structure is proposed

in which an all-pass ring resonator is coupled onto each arm of a symmetric Mach-Zehnder interferometer

realizing the dynamic filtering characteristics of the compound structure.Compared with the conventional symmetric Mach-Zehnder interferometer

this compound optical filter can be used to fabricate optical signal switches with much less power consumption.Thus

it will find important applications in increasing the switch and reducing the power consumption of phase modulators.