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 solitons were investigated. Studies are also carried out measuring the critical power, observing the power variation during transmission and thus discovering the critical points.