Bias-correlated branched-waveguide cascaded light intensity modulator in the scattering matrix formalism

The authors describe the concept of a composite interferometric light intensity modulator constructed in the form of a cascade of 2ⁿ branched-waveguide electrooptic modulators in which the DC bias of the individual modulators are provided in a certain phasing required to yield a high overall modulation efficiency. The analysis of this cascaded modulator, presented in the scattering matrix formalism, predicts that the overall modulation efficiency of the cascade is increased by the factor 2^n/2 compared with that of a single constituent modulator when both are supplied with the same amount of modulating signal power