Bending effects in optical fibers
Bending effects in optical fibers
复制标题
DOI：
10.1109/jlt.1984.1073659
复制
发表时间：
1984-10
影响因子：
4.7
通讯作者：
H. Taylor
中科院分区：
文献类型：
--
作者：
H. Taylor
通过考虑相应直波导的局域简正模，分析了只有一个或几个导模的光纤弯曲处的模耦合。给出拐角处导模之间的耦合强度以及导模和辐射模之间的耦合强度的矩阵元素被计算为这种“几何”效应的导模强度的函数。还确定了由于弯曲光纤中的纵向应变而对这些矩阵元素的修正。根据耦合强度和模式传播常数的信息，计算了包裹在等半径线圈中的光纤的基模传播常数的增加。文中还考虑了光纤轴的空间周期性微弯引起的基模相移和衰减。最后，讨论了这些效应在模式转换器、移相器、开关和传感器等光纤器件中的潜在应用。
Mode coupling at bends in optical fibers supporting one or only a few guided modes is analyzed by considering the local normal modes for the corresponding straight waveguide. Matrix elements giving the strength of coupling between guided modes at a corner bend, and for coupling between guided modes and radiation modes, are calculated as a function of guiding strength for this "geometrical" effect. The correction to these matrix elements due to the longitudinal strain in a bent fiber is also determined. The increase in propagation constant for the fundamental mode of a fiber wrapped in a coil of constant radius is calculated from information on the coupling strengths and mode propagation constants. The phase shift and attenuation of the fundamental mode caused by a spatially periodic microbending of the fiber axis are also considered. Finally, potential applications of these effects in fiber-optic devices such as mode converters, phase shifters, switches, and sensors are discussed.