Mode power evolution in tapered single-mode fiber

This paper reports the investigation of mode power evolution inside a tapered single-mode fiber (SMF). Simulation of the mode power evolution in a tapered fiber with varying waist diameter was performed by BeamProp software. The powers for all modes those exist in the tapered fiber were plotted along the fiber propagation length to study each mode evolution. The simulation results show that the power of the fundamental core mode LP₀₁ decreased as the waist diameter of the tapered SMF was reduced. For the smallest waist diameter of 10 μm, the higher order modes LP₀₂ and LP₀₃ become more dominant. Furthermore, reduction of waist diameter cause the power at the waist region oscillated at higher range and higher frequency.