title: Experimental investigation of all-optical nonreturn-to-zero differential phase-shift keying to return-to-zero DPSK format conversion based on nonlinear polarization rotation of semiconductor optical amplifier.
abstract: A novel all-optical nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) to return-to-zero DPSK (RZ-DPSK) format conversion scheme is proposed and experimentally demonstrated. This conversion is based on nonlinear polarization rotation of a semiconductor optical amplifier. Experimental results show that a 10 Gb/s RZ-DPSK signal with an extinction ratio over 10 dB can be converted with a tunable duty cycle from 33% to 66%, and the ER of the converted signal decreases with the increase in the duty cycle. For all cases of different duty cycles, the converted signals experience a -0.4 to -1.2  dB power penalty at a bit error rate of 10(-9) compared with the original signal. In addition, the spectra show that this format conversion is a wavelength-preserved operation.
authors.forename: Yaya
authors.initials: Y
authors.lastname: Mao
authors.forename: Xinzhi
authors.initials: X
authors.lastname: Sheng
authors.forename: Chongqing
authors.initials: C
authors.lastname: Wu
authors.forename: Kaiqiang
authors.initials: K
authors.lastname: Gao
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Tianyong
authors.initials: T
authors.lastname: Zhang