OICC Press Journal of Theoretical and Applied Physics 2251-7235 19 6 2025 12 31 Design and Performance of an All-Optical Four-‎Channel Filter Based on Linear Photonic Crystals 10.57647/j.jtap.2025.1906.57 EN Elhachemi Kouddad‎ TelecommunicationDigital Signal Processing Laboratory, Faculty of Electrical Engineering, Department of ‎Telecommunications, University Djillali Liabes, Sidi-Bel-Abbes 22000, Algeria https://orcid.org/0000-0001-8983-5634 Ibrahim Yaichi Department of Electrical Engineering, Faculty of Science and Technology. University of Adrar 01000, Algeria Sououdi Boumediene Chabani Department of Electrical Engineering, Faculty of Science and Technology. University of Adrar 01000, Algeria Hassan Dahbi Department of Electrical Engineering, Faculty of Science and Technology. University of Adrar 01000, Algeria Islam Hassani Sustainable Development and Informatics Laboratory (LDDI), University of Adrar, Algeria Journal Article 2025 12 31 In this research, we present a novel design for an all-optical four-channel filter based on two-dimensional photonic crystals (2D PCs). This filter is capable of extracting four distinct wavelengths at each output through various techniques such as ring resonators, scattering rods, and resonant microcavities. We employed two well-established numerical methods: the Plane-Wave Expansion (PWE) method for calculating the band gap diagram and the Finite-Difference Time-Domain (FDTD) method to analyze the light behavior within our filter. The results obtained demonstrate that our proposed filter exhibits exceptional performance characteristics, including a remarkably high transmission efficiency of 99.1%, an outstanding quality factor of 15 628, response time is 9 ps, and minimal crosstalk at -41.6 dB. Furthermore, our operating parameters are compared favorably with recent published works, confirming the filter’s potential for integration into high-speed WDM optical communication systems.