M.Sc Thesis

M.Sc StudentGreenberg Maxim
SubjectIrreversible Optical Devices
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROF. Meir Orenstein


A large family of optical devices is based on employing the interactions between optical modes. Conventionally, a transfer of power from one optical mode to another is achieved by introducing a spatial perturbation of the refractive index (real perturbation). Such power transfer is symmetric from mode n to mode m and vice versa, and reversible in time, which can impede definite performance of many optical devices. We suggest a novel concept, in which by using a matched periodic modulation of both the index of refraction and loss (gain) of the medium, we implement a complex spatially Single Sideband Perturbation (SSP), which breaks the symmetry to allow only a unidirectional energy flow from mode m to mode n, while blocking the inverse flow. In the case of "power flow", the power of the first (incident) mode remains constant, whereas the power of the second mode experiences parabolic growth. For the inverse transition, the power of the incident mode remains constant and the power of the second mode remains virtually zero. Since an implementation of exact SSP can be challenging technologically we investigate various deviations from the ideal resonant condition. We obtain solutions for system with detuning (the period of perturbation is not exactly matched to the difference of propagation constants of the modes); solutions for different real and imaginary coupling coefficients; we investigate the influence of self-coupling coefficients, and the impact of the saturation on unidirectionality. To make the implementation of the SSP more feasible we investigate a separation of real and imaginary perturbations into different spatial locations. SSP is employed as an infrastructure for a number of optical applications - improved broadband “Add” component for OADM system, "One way emitting laser", and "High Q Optical Storage Ring".