An Improvement of Coupling Coefficient for Weakly Coupled Multi Fiber Coupler

摘要

The directional fiber couplers consist of multi fibers joint have been successfully fabricated by heating and pulling the coupling region. Good performance of the coupling coefficient and the coupling ratio was obtained by setting the initial parameter of coupler machine such as the coupling coefficient, pulling speed, pulling length, and heating temperature. The Coupling coefficient of 3-dB fused directional fiber coupler was determined based on perturbation method. A good agreement between theoretical purposed and empirical coupling coefficient from experiment was reported. The coupling coefficient between the waveguides is significantly induced by the distance of separation between them and geometrical coupling region. It is exponentially decreases with increasing separation between fiber axis. However by controlling the coupling coefficient, the desired coupling ratio can be easily attained.