Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We demonstrate broadband second harmonic generation of low-energy pulses produced by injecting two single-frequency lasers into a highly nonlinear fiber. Full nonlinear conversion of the corresponding spectra, consisting of broadband (similar to 200 nm) optical frequency combs at similar to 1580 nm, were obtained by using conventional birefringence phase-matching in two BIBO crystals (2-mm and 100-mu m long) with a normal incidence configuration. The crystals were not tilted and the pulses were not compressed. This broadband conversion results from the large phase-matching bandwidth of the nonlinear BIBO crystals at similar to 1550 nm, but also seems to be a consequence of a fundamental comb with small spectral phase variation. (C) 2009 Elsevier B.V. All rights reserved.283714591462Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CEPOFConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)