It is already foreseen that future integrated photonic circuits for ultra fast alloptical signal processing will require various types of functional elements that include spectral managements. Consequently, dynamical manipulations of the photonic crystals play an important role in order to route the optical signal between waveguide channels or may be among layers. Hence, in this study, photonic crystal based spectral filters are proposed for all-optical communication applications. Firstly, grating structures composed with Gaussian beam interference equation and stimulated by nonlinearity phenomenon in photonic crystal are studied. The grating structure exhibiting special features on transmission characteristics are shown. After that, idea is expanded with applying a realistic Gaussian beam source, and transient grating in nonlinear photonic crystal structure is considered. At this point, light wave interaction with nonlinear response time plays a significant role on the signal manipulation. So, the behavior of pulse propagation in the medium having the response of instantaneous nonlinearity (Kerr) is summarized. As a second aspect of this work, the optical resonator, which is essential functional block for filtering, modulating, buffering, switching in integrated optical circuits systems, is presented. Photonic crystal microcavity based dual-mode dual-band bandpass filter is designed and its transmission characteristics are investigated for various configurations. Photonic crystal resonator structure is formed by a point defect microcavity that is constituted with a large and three smaller auxiliary perturbation rods. Degenerate modes at each band may also be excited by changing the structure properties of the perturbation. The proposed photonic crystal spectral filters structure can effectively be used for optical communication applications.