| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 88 === Fiber-optic couplers are the frequently used devices in the all-fiber commu-nication
systems. More and more complicated fiber-optic couplers have been
fabricated and simulations of such devices with extremely accurate numerical
method are in need in order to perform better design. In this thesis we em-phasize
our study on the analysis of six-port fiber-optic couplers such as the
3 × 3 triangular fused couplers and the 3 × 3 collinear fused couplers and em-ploy
the surface integral equation method (SIEM) to analyze these coupled
structures. The propagaion constants, the mode field patterns, the coupling
coecients, and the form birefringence have been calculated precisely by
dividing the boundary into hundreds of segments using the SIEM. We ap-ply
the uniform and the nonuniform division schemes and make a detailed
comparison. Nonuniform division scheme leads to saving in the computing
time, high accuracy in the calculation of the coupling characteristics, and,
in particular, accurate modeling of the singular behavior of the modal field
near the touching points between adjacent fibers. The eects of geometrical
asymmetry, such as making the fibers to have nonidentical radii, and making
the equilateral triangular 3 × 3 coupler become the isosceles triangular one,
on the mode field patterns and the coupling characteristics are investigated.
|
|---|
