Analysis of photonic crystal fiber for terahertz applications in optical communications

This study discusses photonic crystal fibers (PCFs), a novel type of optical waveguide that performs noticeably better than traditional optical fibers and offers an extraordinary light-guiding mechanism. In this work, a porous core PCF was designed and analyzed. The fiber has a core of 360 μm diameter surrounded by four circular rings of air holes. COMSOL Multiphysics is used to simulate the suggested PCF. By altering two crucial structural components—the pitch spacing, which ranges from 165 to 175 μm, and the diameter (d), which ranges from 140 to 160 μm—the fiber behavior was investigated at frequencies ranging from 0.9 to 1.4 THz. The results demonstrate that dispersion properties exhibit strong dependence on diameter variations, particularly at d=160μm. Analysis of the effective area (Aeff) reveals that it is inversely proportional to frequency, with maximum values observed at d=140, reaching 11.5×10-7 m2. The different effective mode indices of our proposed PCFs are investigated when the diameter d is modified. It can be seen from the results that the effective mode index shows significant sensitivity to the variation of the diameter d, When d=140μm, the effective mode index shows the highest values starting from 1.29 and reaching 1.38, while d=160μm shows the lowest values ranging from 1.23 to 1.35. The medium diameter d=150μm exhibits intermediate values throughout the frequency range. This indicates that the effective mode index changes significantly with diameter variations. the reported design has lower dispersion than the previously reported researches and lower effective area which in turn refer to higher nonlinearity. Hence the suggested design can be used for supercontinuum generation It is possible to fabricate the proposed PCFs by employing the widely utilized sol-gel casting, drilling, and stack and draw techniques. The PCF demonstrates exceptional stability across its operational bandwidth, making it ideal for advanced terahertz sensing and communication applications.