Investigation on selective excitation of 200um polymer cladded silica (PCS) waveguide using eigenmode expansion method / Ahmad Afif Safwan Mohd Radzi

A waveguide or an optical waveguide is the media for light to propagate through inside an insulator. The light or the electromagnetic wave is confined inside the waveguide so that it will flow direct to the next end of the waveguide. There are several types of optical waveguide which is widely used today such as circular, rectangular, tapered and slotted. All of these produce different types and forms of outputs. A waveguide can be compared by its size, where the smaller one, which is nanometer in size, mostly produces single mode wave propagation. The bigger size will have multi-mode wave propagation inside but depends to the beam size. Fiber optics consists of strings of optical waveguide which is prominent as the information transfer medium. It is widely used today inside vehicles as the information and entertainment data medium conveyor. The optical network system requires high efficiency data transportation. Self-imaging and splitting mechanism was investigated to provide better efficiency even in a highly multimode waveguide. Both of the phenomena occurred due to the multimode interference(MMI) inside the waveguide. In this thesis, a highly multimode waveguide of dimension 200umx2um was designed using refractive index of 1.456 for its core and 1.444 for its cladding. The waveguide was excited by Gaussian beam of various sizes. The results obtained show that both self-imaging and splitting mechanism still occur even though the modes were excited using Gaussian beam. Therefore, self-imaging still holds through even in a highly multimode waveguide.