Continuous-wave band translation between the near-infrared and visible spectral ranges

Wavelength conversion based on degenerate four-wave mixing in a photonic crystal fiber with two zero-dispersion wavelengths is investigated both theoretically and experimentally. The proposed concept of universal band translation in a single-pass traveling-wave structure offers a wavelength band rather than a single-wavelength mapping between distant spectral ranges. Near-infrared signals are modulated using both harmonic and pseudorandom bit sequences and translated to the visible optical band. Multiple-channel translation, which produces wavelength-division-multiplexed idlers in the visible band, is demonstrated for the first time. The performance of the translation process is measured both spectrally and temporally for both single- and multiple-channel signals.