Wide-Range Wavelength Conversion of 40-Gb/s NRZ-DPSK Signals Using a 1.3-$\mu$ m Quantum-Dot Semiconductor Optical Amplifier

Wide-range wavelength conversion using dual-pump four-wave mixing in a 1.3-
$\mu{\rm m}$
quantum-dot semiconductor optical amplifier is reported. Nonreturn-to-zero differential phase-shift keying signals of 40 Gb/s were converted over a tunable wavelength range of 45 nm, maintaining the signal fidelity and allowing error-free operation.