Long period gratings in multimode interference devices

The mathematical theory of tilted long period gratings (LPGs) written on multimode interference (MMI) devices is presented in this thesis. Theoretically, long period gratings can be used to change the multimode imaging in a planar waveguide by coupling modes of light. Simulations and designs of these devices are accomplished using MATLAB.;Using long period gratings to couple core-modes to core-modes in order to modify multimode images is presented as a novel concept. This forward-looking concept can be used to create dynamic long period gratings in order to create dynamic optical power splitters or switches. These dynamic long period gratings can be accomplished by using technologies such as thermo-optic materials, electro-optic materials or liquid crystals.