Evolution of nonclassical light propagating through passive optical coupled waveguides: Entanglement dynamic

In this paper, nonclassical light propagation through passive optical coupler is investigated. On the other hand, passive optical device design for nonclassical light is analyzed in this work. Effect of mode mismatching including mismatching in propagation constant on operation of the considered device is studied. We investigate different separable and entangled input excitations with single photons in this case. We specially study the measure of entanglement and effect of propagation constant mismatch on it. The simultaneous effect of loss and mismatch is also studied. Obtained results for different excitation states illustrate that there is a possibility to design such that the system operation can be immune versus fabrication imperfections.