Abstract: A novel perturbative approach to determine the modes of elliptical waveguides is presented. The method is both simpler than the traditional Mathieu function treatment and superior to all previous approximate methods. The method can be used to determine the propagation constants and modal field profiles to any desired accuracy. Bio: Aku Antikainen is a doctoral student in professor Govind P. Agrawal's nonlinear photonics group at the University of Rochester. He got his BSc in mathematics and MSc in engineering at Tampere University of Technology in Tampere, Finland. His current research focuses on supercontinuum generation and other nonlinear effects in optical fibers.