  We theoretically propose a multiparameter cascaded quantum interferometer in
which a two-input and two-output setup is obtained by concatenating 50:50 beam
splitters with n independent and adjustable time delays. A general method for
deriving the coincidence probability of such an interferometer is given based
on the linear transformation of the matrix of beam splitters. As examples, we
analyze the interference characteristics of one-, two- and three-parameter
cascaded quantum interferometers with different frequency correlations and
input states. Some typical interferograms of such interferometers are provided
to reveal more rich and complicated two-photon interference phenomena. In
principle, arbitrary two-input and two-output experimental setups can be
designed with the proposal. This work offers a toolbox for designing versatile
quantum interferometers and provides a convenient method for deriving the
coincidence probabilities involved. Potential applications can be found in the
complete spectral characterization of two-photon states, multiparameter
estimation, and quantum metrology.
