Extended active tunable optical lattice filters enabled by four-dimensional couplers: systems modeling.

A system theoretic model of a unit cell of a two-dimensional tunable lattice filter architecture consisting of four 4-port couplers and four waveguides containing semiconductor optical amplifiers is provided. It is shown that such multiple input-multiple output devices can be modeled in state space and by transfer function matrices. This modeling can also be extended to devices constructed by concatenations of the basic building block, the unit cell.