Cohen L G
Appl Opt. 1976 Jul 1;15(7):1808-14. doi: 10.1364/AO.15.001808.
Dispersive differences between B(2)O(3) and SiCO(2) constituents make nonparabolic profiles optimal equalizers of intermodal group delays in fibers with graded B(2)O(3)-SiO(2) cores and uniform B(2)O(3)-SiO(2) cladding. Pulse dispersion measurements were correlated with profile shapes in a systematic study of multimode fibers with near power law gradients. Far field spatial ray filters were used to diagnose impulse response shapes so that new fibers could be fabricated with closer-to-optimal profile gradients. One of the fibers had an alpha approximately 1.77 power law exponent that was nearly optimal for lambda = 907.5-nm wavelength and caused 2sigma = 0.26-nsec/km full rms output pulse spreading. When expected material dispersion effects were deconvolved from the output pulse spreading, the resultant pulse width was approximately 75 times less than the result expected for a comparable step-index fiber. This is the largest pulse width reduction reported yet.
B₂O₃和SiO₂成分之间的色散差异使得非抛物线型分布成为具有渐变B₂O₃ - SiO₂纤芯和均匀B₂O₃ - SiO₂包层的光纤中模间群时延的最佳均衡器。在对具有近幂律梯度的多模光纤进行的系统研究中，脉冲色散测量与分布形状相关。远场空间射线滤波器用于诊断脉冲响应形状，以便能够制造出具有更接近最佳分布梯度的新光纤。其中一根光纤的α约为1.77幂律指数，对于λ = 907.5 - nm波长几乎是最佳的，并且导致2σ = 0.26 - nsec/km的全均方根输出脉冲展宽。当从输出脉冲展宽中解卷积出预期的材料色散效应时，所得脉冲宽度比可比阶跃折射率光纤预期的结果小约75倍。这是迄今报道的最大脉冲宽度减小。
