All-optical pulsewidth-tunable wavelength conversion of return-to-zero differential phase-shift keying signal

We demonstrate the wavelength conversion of return-to-zero differential phase-shift keying (RZ-DPSK) signal with the pulsewidth-tunable operation using a Raman amplifier (RA)-based ultrashort pulse compressor and a highly nonlinear fiber (HNLF)-based four-wave mixing (FWM) switch. The wavelength of the input RZ-DPSK signal is converted to new wavelengths owing to the FWM effect in HNLF. On the other hand, the pulsewidth of the wavelength-converted RZ-DPSK signal is tuned from 10 to 3 ps by using the ultrashort pulse source based on RA-based adiabatic soliton pulse compression. The bit error rate characteristics of the input RZ-DPSK and the wavelength-converted RZ-DPSK signals with different pulsewidths are measured and error-free operations are achieved in all cases. The optical spectra, autocorrelation traces, and clear and opening eye diagrams show high conversion performance with wide-range pulsewidth tunability. © 2015, The Optical Society of Japan.