Research on the phase properties of 2 x 2 single-mode fiber coupler

摘要

The phase properties at the output ends of 2 x 2 single-mode fiber couplers are investigated in detail. Considering the coupler's loss but not the birefringence, the phase difference between the two output ends is studied. It shifts less than 3 degrees from the phase difference without considering the loss. Taking account of the fiber's birefringence, the phase retardance between the two orthogonal components at the end of the throughout/coupled arms, the mathematical expression is given and influences of the working wavelength, the environment refractive index and the effective coupled length on the retardance are simulated. Error between theoretical results and experimental results is 7.374%. With a linear polarized light input, the output light develops into an elliptical polarization. (C) 2014 Elsevier GmbH. All rights reserved.