Bismuth-oxide-based nonlinear fiber with a high SBS threshold and its application to four-wave-mixing wavelength conversion using a pure continuous-wave pump

The unique and practical benefits of the use of bismuth-oxide-based nonlinear fiber (Bi-NLF) in implementing a four-wave-mixing (FWM)-based wavelength converter for fiber-optic-communication-system applications are experimentally demonstrated. First, the Kerr-nonlinearity and stimulated-Brillouin-scattcring (SBS) characteristics of our fabricated Bi-NLF are experimentally investigated. The Bi-NLF is found to have the superior advantage of a significantly high SBS threshold in addition to its ultrahigh Kerr nonlinearity γ of ∼ 1100 W^-1 · km^-1, compared to the conventional silica-based highly nonlinear fiber. Next, the authors perform an experiment for the FWM-based wavelength conversion of a non-return-to-zero (NRZ) signal within a 40-cm length of the Bi-NLF fusion spliced to standard silica fibers by using a continuous-wave (CW) high-power pump beam. Error-free tunable wavelength conversion over a 10-nm bandwidth is readily achieved. No SBS-suppression scheme is employed for the pump due to the high SBS threshold, which simplifies the system configuration and improves the quality of the wavelength-converted signal.