A Simplified Coupling Power Model of Single Mode Fiber Fusion at Coupling Length

Fabrications of single mode fiber coupling by heating fibers on a flame are very common and popular. However, controlling the output power of fiber coupling process is neither easy nor similar. Power losses occur at the coupling length due to geometrical change of the fibers after fusion. The power losses will affect sensor devices such as an optical switch. This paper proposes power splitting into the second fiber junction in terms of a new model by deriving the coupling power with two conditions of refractive index changes. First is the change in the vertical part and second is the change in the vertical and horizontal part simultaneously. Both conditions are studied by perpendicular and parallel directions. The model is examined where power absorption and reflection are accumulated by power losses. Simulation result shows that the power increases by superposition wave. These power losses are due to radiation out of the cladding and fiber heating.