Abstract

The magnitude and dispersion of the nonlinear refractive index are crucial parameters for transmission of high power pulses through optical waveguides. Although the wavelength dependence is usually weak in conventional waveguides like standard fibers, the nonlinear refractive index is expected to change more drastically near the bandgap of photonic bandgap waveguides like hollow core fibers. Consequently, the nonlinear refractive index of the carrier, $n_2^{\text{phase}}$, and of the group, i. e. the pulse envelope, defined as $n_2^{\text{group}}=n_2^{\text{phase}}-\lambda d{n}_2^{\text{phase}}/d\lambda$ become different in this wavelength region. It may lead to excess carrier-envelope-offset (CEO) phase noise of optical frequency combs after transmission through a hollow-core fiber. Such excess CEO phase noise arises due to different AM-PM conversion for the carrier phase and envelope timing [1].

© 2009 IEEE