@ARTICLE{ :/content/journals/10.1049/ij-moa.1977.0027, author = {J.M. Arnold}, keywords = {asymptotic evaluation;optical waveguide;large meridional order;normalised cut off frequency;quadratic index variation;}, ISSN = {0308-6976}, language = {English}, abstract = {Asymptotic expressions for normalised cut-off frequencies of modes having large meridional order n and small azimuthal order m are obtained for an inhomogeneous waveguide having quadratic index variation. A fractional integral technique is used to construct solutions directly from the differential equation in the form of an integral representation, which is expanded by the steepest-descent procedure.}, title = {Asymptotic evaluation of the normalised cut-off frequencies of an optical waveguide with quadratic index variation}, journal = {IEE Journal on Microwaves, Optics and Acoustics}, issue = {6}, volume = {1}, year = {1977}, month = {November}, pages = {203-208(5)}, publisher ={}, copyright = {© The Institution of Electrical Engineers}, url = {https://digital-library.theiet.org/;jsessionid=18se7w42hv3bt.x-iet-live-01content/journals/10.1049/ij-moa.1977.0027} }