Optic add-drop multiplexers

The internet and information technologies have rapidly been progressing lately and data, sound and video traffic keeps getting more and more congested. Due to these reasons, the amount of data conveyed at computer networks increases exponentially. This constantly gives rise to the need for more bandwidth. To meet this demand in the presence of existing network infrastructures seems difficult in the future. Optic fibers are the most likely choice available for communication channels that can be used to meet the increasing demand. No matter how much wider the bandwidths of fiber optic cables are than those of other transmission components, in order to benefit, as much possible as, from the bandwidth offered by fiber channel, different multiplexer techniques must be used. Optic Add Drop Multiplexer (OADM) is the most basic way to increase the capacity of communication network.This thesis have been based on the design of optic add drop multiplexer with different radii (3-6 µm). This design has been carried out with silicon on insulator (SOI). SOI waveguides which have same geometry were used in design of optic add drop multiplexers. This design has been carried out with numerical approximations based on Beam Propagation Method (BPM) and Finite Difference Time Domain (FDTM) Method.Effective index, bending losses and coupling ratios of SOI waveguide were calculated by the conventional simulation program based on Finite Difference Time Domain (FDTD) Method. Designs of optic add drop multiplexer are presented in detail. As dimension of SOI waveguides decreases, the polarization dependence of this waveguide increases. Therefore, the calculations were performed only for TE polarization in this thesis. As the radius of optic add-drop multiplexer decreases, free spectral range of this structure (cavity) increases. It has been seen that with decreasing of cavity radius from 6 µm to 3 µm, the free spectral range increases from 26 nm to 47 nm in this work. It has been obtained that the quality factor equal to 632 of SOI cavity in the result of this thesis. In addition, as a preliminary work we mentioned to production of optical add-drop multiplexors. Optical microscope and SEM images of the optical add-drop multiplexors fabricated in Advanced Research Laboratuary of the Department of Physics at Bilkent University were presented in this thessis.Key Words : Waveguide, BPM, FTDT, Optic Add Drop Multiplexer