In this research work, dielectric photonic crystal (PhC) structures based on low refractive index slab waveguide are investigated. These two-dimensional slab waveguide PhC structures work on the principle of guided-mode resonance and find their application in optical filters operated in the near-infrared range. The design and numerical simulation of the presented PhCs are carried out using finite-difference time-domain (FDTD) method. The dielectric materials used in the presented structures are zirconium dioxide/niobium pentaoxide (ZrO2/Nb2O5) for the waveguide layer and silicon dioxide (SiO2) as surrounding medium and substrate. The study includes the effect of structural features and design layouts on the transmission characteristics of the PhC filters. The dielectric PhC structures are implemented using focused ion-beam milling lithography and the fabrication results are used as an experimental input for numerical simulations. Dielectric PhC filters are also investigated on the basis of provided experimental data from material processing using high energy femtosecond (fs) laser pulses. The effects of various structural features of the high-aspect ratio holes generated by fs-laser pulses on the performance of PhC filters are discussed. Moreover, various challenges regarding the optical characterization of the dielectric PhC filters are also numerically investigated. These challenges include the finite size of the source, its angular spectrum and spot size, and the finite size of the structures. Some properties related to the existing optical characterization setup at the laboratory are also numerically investigated to improve the measurement method.