Direct-detection optical differential 8-level phase-shift keying (OD8PSK) for spectrally efficient transmission

University of Central Florida, Orlando, Florida, United States
Optics Express (Impact Factor: 3.49). 08/2004; 12(15):3415-21. DOI: 10.1364/OPEX.12.003415
Source: PubMed


An implementation of optical differential 8-level phase-shift keying (OD8PSK) is proposed for spectrally efficient high capacity long-haul optical fiber transmission systems. Interferometric demodulation and direct detection at the receiver yield three output binary sequences identical to the three input binary sequences. This is accomplished by proper design of electrical encoding and optical encoding at the transmitter. Three optical encoding schemes are proposed with corresponding differential electrical encoding schemes. Numerical simulations are performed for a single channel transmission to evaluate the transmission performances of OD8PSK systems.

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Available from: Guifang Li, Oct 01, 2015
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    • "Here the optical narrow band filtering tolerance for two modulator implementations of directly detected NRZ-D8PSK signal for different receiver demodulator parameters is studied in detail through numerical simulations. The first modulator implementation is the conventional cascaded modulator [3] consisting of a DQPSK modulator and a phase modulator (PM). The other is recently proposed quad-parallel Mach-Zehnder modulator (QPMZM) structure [4]. "
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    ABSTRACT: The influence of optical filtering on direct detected NRZ-D8PSK system is investigated for two modulator implementations. Better tolerance to filtering can be achieved for parallel implementation of a 112 Gb/s signal in 50 GHz spacing system.
    OptoeElectronics and Communications Conference (OECC), 2010 15th; 08/2010
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    • "The demodulated signal was detected by balanced detectors having 28 GHz bandwidth. The architecture of DQPSK/D8PSK demodulator [7] is shown in Figure 3a and Figure 3b. OSNR measurement was done at 0.1 nm. Figure 4 shows the spectrum of the signal in the single channel as well as WDM scenarios. "
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    ABSTRACT: In this paper, 40 Gbaud transmission of single polarization (SP) and Polarization-Multiplexed (PM), RZ-DQPSK and RZ-D8PSK signals is analyzed numerically. The impact of nonlinear crosstalk arising from the presence of neighbouring intensity-modulated channels is analyzed in terms of required OSNR for the BER of 10<sup>-3</sup> versus launch power.
    Transparent Optical Networks (ICTON), 2010 12th International Conference on; 08/2010
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    • "As a result, multi-level modulation formats have received particular attention since they can exhibit high bandwidth efficiency and thus better dispersion tolerance [1]. In terms of embodiment, multi-level intensity modulation [2] [3] [4], multi-level phase modulation [5] [6] and hybrid multi-level phase and intensity modulation [7] [8] [9] can be utilized due to different potential advantages. While multi-level modulation techniques are investigated extensively, relevant signal processing techniques such as format conversion for multi-level formats are very lacking. "
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    ABSTRACT: We propose and demonstrate a multi-level all-optical format conversion from NRZ signal to RZ signal, using a semiconductor optical amplifier (SOA) and a detuned optical filter. The three-level NRZ signal and a synchronous optical clock signal are injected into an SOA, which acts as a nonlinear element and causes the spectrum of the input NRZ signal to be broadened due to the cross phase modulation (XPM) effect. A detuned filter is thus used to extract the specific part of the broadened spectrum to obtain three-level RZ signal. The proposed conversion can be achieved with error free at 10G baud rate.
    Communications and Photonics Conference and Exhibition (ACP), 2009 Asia; 12/2009
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