基于Pade逼近的非迭代双向光束传输法

Non-iterative bidirectional beam propagation method using Pade approximants

平方根算子有理逼近是双向光束传输法的必要步骤,其逼近精度决定了双向光束传输法计算结果的精度和有效性。采用Pade逼近有理化平方根算子,分别计算四种不同Pade逼近方式下的反射光场和透射光场,比较了基于不同Pade逼近方式的非迭代双向光束传输法计算结果的稳定性和有效性。

Accurate rational approximation to the square root operators is crucial for bidirectional beam propagation method（BIBPM）,which is relevant to damping of evanescent modes.Especially,it is essential to simulate the optical waveguide with significant longitudinal refractive index contrast.The range of numerical instability and validity in BIBPM associated with the use of different Pade approximations is studied by investigating the waveguide with varying refractive index.