LAUSR

Based on the wave-particle duality of light, the Schrödinger equation for a photon as a particle is established to treat the light coupling effect by introducing concepts of the virtual mass and potential for a photon, which is different from the previous method that uses the analogy with quantum mechanics. The virtual mass is physically correlated to the kinetic energy according to Einstein’s energy–momentum relation. As a consequence, this new model has merits of physical simplicity and analytic nature. This new model can well explain the exponential dependence of the light coupling effect on the physical parameters in coupled waveguides on, which can be observed in the experimental and simulation data reported in the literature. Moreover, an explicit expression for the coupling length (coefficient) on the effects of physical parameters can be obtained by virtue of this new model, whereas the previous modal approach and the coupled-wave model resulted in implicit expressions. This new model does not only give a better physical understanding but also offers a possibility to design and fabricate optic devices based on the light coupling effect by optimizing the physical parameters.