Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Future Internet infrastructure will require the utilization of new all-optical devices able to enhance the use of fiber capacity. Nevertheless, before deploying such devices, it is necessary to test them under conditions similar to the ones of commercial networks and to evaluate their impact on real-world applications. In this work we investigate the performance of a tunable fiber four-wave mixing all-optical wavelength converter (AOWC) on a video-streaming carried through a field-trial network. This analysis is performed by measuring the packet-error rate (PER) degradation caused by the AOWC for different wavelength separations between the input and output optical carriers. To the best of our knowledge, this is the first time that such a cross-layer effect is systematically evaluated for an AOWC. A dynamic polarization controller was successfully used to prevent the FWM efficiency variations that were caused by the changes in the state-of-polarization of the video signal. Our results show that the AOWC introduced a maximum power penalty of 2.5 dB for wavelength separations of up to 12 nm. We also find that such a penalty is related to the optical signal-to-noise ratio degradation induced by the converter.271218161826Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho 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)CNPq [03/08320-2, 03/08196-0, 06/50911, 08/57857-2, 574017/2008-9]