This is a C++ library (a part of it is based on FORTRAN) to compute (double precision) Bessel functions of first kind (J), Bessel function of second kind (Y), Hankel function of first kind (H1) and Hankel function of second kind (H2); and their first derivative w.r.t. argument for REAL/COMPLEX ORDER and REAL/COMPLEX ARGUMENT.

The implementation is based of 'Uniform Asymptotic Expansion of Bessel functions in terms of Airy functions' as described in 'Handbook of Mathematical Functions' by Abramowitz and Stegun (1964).

For the computation of complex valued Airy function, FORTRAN routines of Amos are used. These are available at www.netlib.org

The emphasis is on the utility of the routines for large (complex) order and large argument.

Caution : Routines show numerical instabilities for the case when the absolute value of ratio of order to argument is close to 1.

Source code     More info

This simulator implements a semianalytical 2D microresonator model. Analytical solutions for modes supported by bend segments and straight channels are combined in a framework of frequency domain coupled mode theory. The resonator is functionally decomposed into two bent-straight waveguide couplers, which are connected to each other by segments of bent waveguides.

The C++ implementation provides objects for straight and bent waveguides, coupler configurations, and full microresonator structures. The latter includes methods for the evaluation of the power transmission, the free spectral range, the width of the resonances, and, for given vacuum wavelength, of the full (2D) optical fields. Scans over the wavelength parameter permit to compute the spectral response of the microresonator device.

Source code and user manual: Circurs