Abstract
The effect of fusion and coupling parameters to the form of birefringence of coupling region directional fiber coupler is reported. Vector of polarization was determined by using perturbation method that describes the propagation of electric field in single mode fiber coupling induced by stress which is caused by fusion and coupling parameters during fabrication. It is found that the geometrical change, such as radius of coupling cross section, refractive index difference, normalized frequency, and twisting angle significantly affect the polarization and birefringence. However, change of temperature during fusion in range 27-1350 degrees C gives only small increment in birefringence directional fiber coupler. By knowing these parameters, the polarization and birefringence can be maintained and optimized for polarization maintaining fiber coupler application. (C) 2012 Elsevier GmbH. All rights reserved.