This application example represents a device named ring-loaded Mach-Zehnder which comprises a
Mach-Zehnder Interferometer with a delay ring in one of its arms
This arrangement might perform as an interleaver filter or as an optical filter with a flat response, depending on the
length of the ring and the path difference at the upper and lower branches.
In this design, the length difference has been chosen one-half of the length of the ring so it
features an interleave filter. The resultant FSR is given by FSR = c / n_g*LengthDifference, with "c" being the velocity of
light, "n_g" representing the group index and "LengthDifference" showing the length difference between upper and lower arms. The flatness
and the extinction ratio depend on the coupling coefficient at the couplers and the ring-waveguide coupling.
shows the transfer function of the cross and bar outputs for two values of the ring coupling.
Keywords: Ring coupler, Ring-loaded, MZI, Photonic Integrated Circuits, PICs
Similar demonstrations are available in VPIComponentMaker Photonic Circuits and on the VPIphotonics Forum.