Single-stage Mach-Zehnder Modulator Research Articles

Review on photonic method for generating optical triangular pulses

In this paper, several photonic generating methods for optical triangular pulses were reviewed. Four frontier research methods for generating optical triangular pulses were introduced, these four methods are respectively based on the frequency-to-time conversion, using normally dispersive fiber, by single-stage dual-drive Mach-Zehnder modulator (MZM), and using dual-parallel MZM. These four methods can be classified into two categories in terms of the optical source employed, such as mode-lock laser (MLL) and continuous-wave (CW) respectively. Compared with the methods based on MLL, those based on CW have many advantages, such as simpler structure, lower price, higher stability, more flexible and wider tunability. Besides, the method using single-stage drive MZM can generate versatile waveform optical pulses, which has better performance than the first two methods in tunable capability of both repetition rate and center wavelength. With the same driving signal applied, the optical source using the dual-parallel MZM can generate signal with higher frequency than that of using the single-stage MZM.

A novel optical picosecond-duration NRZ-to-RZ format converter with simultaneous wavelength multicasting using a single-stage Mach–Zehnder modulator

We propose a novel and simple scheme to achieve NRZ-to-RZ format conversion and simultaneous wavelength multicasting based on a single-stage dual-arm electro-optic Mach–Zehnder modulator (MZM) and a short single mode fiber (SMF). The format conversion and wavelength multicast process are achieved by chirp compensation under the condition of generation of optical flat frequency comb. 40Gb/s NRZ-to-RZ conversion with one-to-five multiple-wavelength channel multicasting and transmission of the NRZ and the converted signals over 200km dispersion-managed fiber-link are successfully demonstrated by numerical simulation. Research results show that 40Gb/s 2ps RZ signal with wavelength-preserving can be obtained after format conversion. The converted RZ signal presents good transmission performance and can easily be multiplexed to 160Gb/s using optical time division multiplexing (OTDM) technology. All the multicast channels can be error free after 50km transmission. Besides, the conversion operation can also greatly reduce the timing jitter of the degraded NRZ signal due to the retiming function of the proposed scheme.

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.

Electrically band-limited CSRZ signal with simple generation and large dispersion tolerance for 40-Gb/s WDM transmission systems

We present a novel configuration for carrier-suppressed return-to-zero (CSRZ) signal generation, which only requires a single-stage Mach-Zehnder modulator in conjunction with an electrical mixer. An electrical band-limiting filter is also introduced to further reduce the spectral width of the generated CSRZ signal. The proposed scheme is potentially cost-effective, and simulation results show that the electrically band-limited CSRZ signal exhibits larger dispersion tolerance than a conventional CSRZ signal without any degradation in its nonlinearity tolerance.

Compact-spectrum RZ signal generated by single-stage push–pull type Mach-Zehnder modulator for DWDM transmission

A novel compact-spectrum RZ signal is proposed; its bandwidth is approximately twice the bit rate. It is generated by a single-stage Mach-Zehnder modulator with 2:1 multiplexing function. 50 GHz-spaced 8×20 Gbit/s DWDM transmission is realised.