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Recently, high-speed optical transmission using single-side-band (SSB) modulation with Kramers-Kronig (KK) scheme has gained great attention due to its high spectral efficiency (SE) and capability of electronic chromatic dispersion compensation (CDC), which can be widely employed in optical metro networks as a promising transmission scheme. To our knowledge, the carrier-signal power ratio (CSPR) is the key parameter to SSB-based systems and the optimum CSPRs can vary distinctly in different SSB modulation schemes. In this paper, the SSB-based KK systems with four kinds of SSB signal generation schemes are investigated, i.e. optical carrier-assisted SSB (OCA-SSB), virtual carrier-assisted SSB (VCA-SSB), SSB subcarrier modulation (SSB SCM) with IQ modulator (IQM) and with dual-drive Mach-Zehnder modulator (DDMZM) respectively. Here, the detailed theoretical derivations of these modulation processing are given and the theoretical relationship between device parameters and the CSPR has been further studied for the different SSB schemes. In order to verify those theoretical analyses, a 224-Gb/s direct detection (DD) transmission with SSB 16-ary quadrature amplitude modulation (16-QAM) signal has been demonstrated based on four SSB generation methods. The results show that theoretical derivations are closely consist with numerical analysis, such as $V_{bias}$ in the scheme of SSB SCM with IQM and optical modulation index (OMI) in SSB SCM with DDMZM. Therefore, our research can provide a theoretical guidance of appropriate device parameter configuration so as to achieve the optimum performance for SSB systems.

Abstract Benefiting from the high spectrum efficiency and power efficiency, 6PolSK-QPSK (6-ary polarization-shift keying quadrature phase-shift keying) is a promising modulation format in coherent optical communication. We proposed a novel structure to generate the 6PolSK-QPSK with two dual-drive MZMs. Simulation results show that the proposed structure can generate 6PolSK-QPSK effectively and the performance is nearly the same to the traditional one.

A microwave photonic generation scheme of triangular waveform using cascaded dual-drive Mach-Zehnder modulators (DDMZMs) and FBG is proposed. We show that a frequency-doubled and power-variable triangular waveform can be obtained. The double frequency can reduce the high-frequency requirement of the local oscillation signal (LO) source. The introduction of the second modulator can improve the stability of the scheme. The simulation results show that the power of the triangular is variable; the stability is optimized when the first modulation index is in 0 1; the similarity coefficient is greater than 0.998, which is 0.006 higher than one-stage-modulation scheme. Meanwhile, the similarity coefficient remains over 0.992 when the DC drifting difference value of and is in −90 60 mV, and it remains over 0.99 when the phase difference of the two LO sources varies from −10° to 10°. It verifies the tolerance of DC drifting and phase desynchrony of the system. [ABSTRACT FROM AUTHOR]

Recently, single-side-band (SSB) modulation direct detection (DD) based optical transmission systems have attracted great interest due to their capability of electronic chromatic dispersion (CD) compensation. In this paper, we investigate the digital chromatic dispersion pre-management for optical SSB signals which are generated by radio frequency (RF) tone based on I/Q modulator and optical carrier based dual-drive Mach–Zehnder modulator (DDMZM) with DD at the C-band via numerical simulations. The impact of CD, self-phase modulation (SPM) and phase-to-amplitude noise on such a SSB DD optical transmission system with I/Q modulator based virtual carrier assisted, and the DDMZM based optical carrier are investigated. The simulation results have successfully demonstrated the transmission of a 224-Gb/s Nyquist 16-ary quadrature amplitude modulation (16QAM) signal over 75-km standard single mode fiber (SSMF) with bit error rate (BER) less than 3.8 × 10 −3 in a SSB-DD system by using digital CD pre-management. It is shown that the SPM induced impairment can be optically mitigated by the residual positive CD of the SSMF link. [ABSTRACT FROM AUTHOR]

Benefiting from the high spectrum efficiency and power efficiency, 6PolSK-QPSK (6-ary polarization-shift keying quadrature phase-shift keying) is a promising modulation format in coherent optical communication. We proposed a novel structure to generate the 6PolSK-QPSK with two dual-drive MZMs. Simulation results show that the proposed structure can generate 6PolSK-QPSK effectively and the performance is nearly the same to the traditional one. [ABSTRACT FROM AUTHOR]

We propose and experimentally demonstrate a reconfigurable ultrawideband (UWB) pulse generation scheme by using a dual-drive Mach-Zehnder modulator (DDMZM). In the proposed method, two phase modulators of the DDMZM are respectively driven by properly designed electrical signals. By carefully setting the parameters of the two electrical signals and the bias voltage of the DDMZM, different UWB pulses can be achieved at the interference output of the DDMZM. A proof-of-concept experiment verifies the feasibility of the proposed method. Photonic generations of UWB monocycle, doublet, triplet, and quintuple pulses have been successfully demonstrated, with central frequencies of 4.69, 4.69, 5.47, and 6.25 GHz and fractional bandwidths of 150%, 133%, 186%, and 75%, respectively. [ABSTRACT FROM PUBLISHER]

We propose and experimentally demonstrate a new method to generate a 3-D ultrawideband (UWB) signal by utilizing a dual-drive Mach-Zehnder modulator (DDMZM). Three degrees of freedom of the generated 3-D UWB signal are pulse position, pulse phase, and pulse amplitude. In this scheme, each radio frequency (RF) port of the DDMZM is modulated by a combination of two encoded signals with different amplitudes. By properly adjusting the amplitudes of the encoded signals and the bias voltages of the two RF ports, a 5-Gb/s 3-D UWB signal with a central frequency of 3.5 GHz and a 10-dB fractional bandwidth of 163% is successfully generated by using only a single DDMZM. [ABSTRACT FROM PUBLISHER]