This work presents an analysis of the coupling coefficient (C), observing the behavior of the fiber with three waveguides with a triangular arrangement, based on Photonic Crystal Fiber (PCF). The numerical study was based on solving the pair of equations for coupled modes using the Runge-Kutta numerical method. Initially, the propagation properties of ultrashort pulses with a temporal width of 100 femtoseconds (fs) of light in the form of fundamental...