Electrically band-limited CSRZ-DPSK signal with a simple transmitter configuration and reduced linear crosstalk in high spectral efficiency DWDM systems

In this letter, we propose a novel transmitter configuration for generating electrically band-limited (EB) carrier-suppressed return-to-zero (CSRZ) differential phase-shift-keyed (DPSK) signals, which requires only a single-stage Mach-Zehnder modulator in conjunction with an electrical band-limiting low-pass filter and electrical mixer. The proposed scheme is cost-effective due to the simple configuration. In addition, when applied to dense wavelength-division-multiplexing systems with high spectral efficiency, the EB-CSRZ-DPSK signal exhibits reduced linear crosstalk, increased dispersion tolerance, and no additional nonlinearity penalty in comparison to the conventional CSRZ-DPSK signal.