Origin of spurious modes in the analysis of optical fibre using the finite-element or finite-difference technique

[[abstract]]An origin of spurious modes in the finite-element or finite-difference analysis of optical fibres is found. Such spurious modes are due to the ill-condition in the resultant matrix equation, which occurs whenever the propagation constant approaches the average between the permittivities of two consecutive node points employed.[[fileno]]2030130010041[[department]]電機工程學