从本征方程式[k~2n~2(r)-β~2m_L-(m~2)/(r~2)]~(1/2)=(l+1/2)π中求出各模式的传播常数βm_L。此后共用四种方法计算光导纤维的通频带宽度。①通过求均方根脉冲宽度求带宽,②利田系统频率特性求带宽。③用付利叶变换求带宽;④用曲线拟合,由介析式求带宽 Each mode is determined from the intrinsic equation [k~2n~2 (r) -β~2m_L- (m~2) / (r~2)] ~ (1/2) = (l + ½) π The propagation constant βm_L. Four methods are then used to calculate the passband of the optical fiber. ① by seeking the root mean square pulse width and bandwidth, ② Lee Tian system frequency characteristics and bandwidth. ③ use Fourier transform to find the bandwidth; ④ curve fitting, by the analytical type of bandwidth