Journal of Applied Sciences ›› 1995, Vol. 13 ›› Issue (2): 184-188.

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LOCAL FIELD IN A SINGLE -MODE HELICAL FIBER

CHEN GUANSAN   

  1. Shanghai University, Jiading Campus
  • Received:1993-05-31 Revised:1993-11-05 Online:1995-06-30 Published:1995-06-30

Abstract: Based on the wave equation,we directly analyse a single-mode helical fiber with a circular cross section and step profile of the refractive index in the local coordinate system. Withe the perturbation method,the analytical expressions of the fundamental mode field and the propagation constant are given,Two results are brought about:(1) the fundamental modes in a single-mode helical fiber are right-rotated and left-rotated circularly polarised modes. (2) the difference of propagation constants between the two modes iS 2τ.The theoretical results agree with those of the known experimental measurements.

Key words: circularly polarised modes, nonorthogonal coordinate system, helical fiber