Dynamic analysis of an optical fiber coupler in telecommunications

This paper studies the vibration of an optical fiber coupler which is used in telecommunications subjected to a half sine shock. The emphasis is focused on analyzing the vibration response of the optical fibers inside the coupler and examining the influence of various coupler parameters on the vibration of the optical fibers, since their dynamic behavior is a critical factor in optical fiber communications. A simplified model of the optical fiber coupler is proposed, which consists of a beam and a string representing the substrate and the bundle of the optical fibers of the coupler, respectively. The beam and the string are bonded at four points using adhesive material, and therefore the boundary conditions for their equations of motion are coupled, which increases the complexity of the problem. For the string, two models are developed— the linear model assumes that the tension in the string is constant, while the non-linear one takes into account large transverse deflection and tension variation. With each model, both analytical study and numerical simulations for the vibration of the system under a half shock are carried out. Furthermore, numerical results are compared between the two models. Finally, parametric study leads to conclusions which are of practical importance to the design of optical fiber couplers.