Graphene as an inhomogeneously broadened two-level saturable absorber.

We show that the inter-band optical conductivity of graphene follows a dependence on intensity that is characteristic of inhomogeneously broadened saturable absorbers, and we obtain a simple formula for the saturation intensity. We compare our results with those from more exact numerical calculations and selected sets of experimental data, and obtain good agreement for photon energies much larger than twice the chemical potential.

High-order dispersion mapping of an optical fiber.

We report on measurements of high-order dispersion maps of an optical fiber, showing how the ratio between the third and fourth-order dispersion (β/β) and the zero-dispersion wavelength (λ) vary along the length of the fiber. Our method is based on Four-Wave Mixing between short pulses derived from an incoherent pump and a weak laser. We find that the variations in the ratio β/β are correlated to those in λ.

Shift of zero-dispersion wavelength in bent optical fibers.

The understanding of how bending modifies the dispersion of optical fibers, in particular, the zero-dispersion wavelength (λ), is essential in the development of compact nonlinear optical devices such as parametric amplifiers, wavelength converters, soliton lasers and frequency comb generators. Typically, substantial variations in the parametric gain and/or conversion efficiency are significant for changes in λ of ~0.1 nm, which occur for variations on the bending radius (Rb) of 1 cm or less.

Broadband single-polarization guidance in hybrid photonic crystal fibers.

We present hybrid photonic crystal fibers that provide broadband single-polarization guidance based on two different propagation mechanisms, namely, total internal reflection and the photonic bandgap effect. Experimental results demonstrate polarization dependent loss as high as 26.7 dB and the bandwidth of single-polarization behavior over 225 nm.

Efficient calculation of higher-order optical waveguide dispersion.

An efficient numerical strategy to compute the higher-order dispersion parameters of optical waveguides is presented. For the first time to our knowledge, a systematic study of the errors involved in the higher-order dispersions' numerical calculation process is made, showing that the present strategy can accurately model those parameters. Such strategy combines a full-vectorial finite element modal solver and a proper finite difference differentiation algorithm.