Simulation of Self-Image Interference in Single Mode-No-Core-Single Mode Fiber with COMSOL Multiphysics®

Self-image interference in a single mode-no-core-single mode fiber plays an important role especially for length optimization before acting as a sensor. The interference can be observed through optical simulation software. Past literature has successfully demonstrated the interference via COMSOL Multiphysics®, but the simulation was not restricted to the use of important domains and settings such as perfectly matched layer and surrounding domain causing imprecise simulation results. This paper proposes a simulation of self-image interference in a single mode-no-core-single mode fiber by using the wave-optics module in COMSOL Multiphysics® software. The beam propagation method is used to observe the self-image interference for different self-image indexes ranging from one to four indexes while the self-image length is obtained from the theoretical calculation before a simulation is carried out. The results show that accurate results can be obtained with restricted simulation settings. The number of the self-image index and self-image length produced by the simulation are similar to the calculation. The self-image point is located exactly at the calculated length with a four-decimal point 0.0000 difference, thus overcoming the limitation of the simulated previous work. In the future, the simulation settings and results can be used for reference to simulate the single mode- no-core-single mode fiber structure.