All-Optical regeneration of differential phase-shift keyed signals based on phase-sensitive amplification

Center for Research and Education in Optics and Lasers, University of Central Florida, Orlando, Florida, United States
Optics Letters (Impact Factor: 3.29). 11/2004; 29(20):2357-9. DOI: 10.1364/OL.29.002357
Source: PubMed


All-optical regeneration of differential phase-shift keyed signals based on phase-sensitive amplification in a nonlinear fiber Sagnac interferometer is described. Nearly ideal phase regeneration can be achieved in the undepleted pump regime, with output differential phase noise limited only by fast fluctuations of the pump phase relative to the DPSK signal. Operating in the depleted pump regime offers the possibility of simultaneously regenerating both phase and amplitude information of DPSK signals while providing low noise, phase-sensitive gain.

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Available from: Guifang Li,
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    • "In fiber optic systems phase-sensitive amplification can be realized either through the use of a nonlinear optical loop mirror (NOLM) [8], [9] or via four-wave mixing [14]–[16]. While both have successfully been demonstrated, the four-wave mixing approach is advantageous as it offers the possibility of using multiple channels and therefore supports wavelength division multiplexing (WDM) type applications. "
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    ABSTRACT: The properties of phase-sensitive amplification (PSA) in highly nonlinear fibers are studied. We present a soft glass fiber designed for high nonlinearity and broadband, low dispersion and simulate its performance as a PSA device for ultrafast bitrate signals at 640 Gb/s. The effect of the fiber design parameters on its PSA performance have been studied and the final design has been optimized using a genetic algorithm to have a high nonlinearity and low, flat dispersion. This design has subsequently been compared to other highly nonlinear fibers in order to highlight the effect of both using soft glass and the design and optimization technique. Modelled fiber performance shows squeezing of phase noise in a 5 m length of fiber with 32 dBm total power in the signal and pumps. The fiber length we have used in our model is two orders of magnitude shorter than the state of the art silica based PSA devices for comparable power levels. In addition, fabrication tolerance modelling is done to show that our fiber design is better able to manage fluctuations in the dispersion due to the high nonlinearity.
    Journal of Lightwave Technology 11/2012; 30(21):3440-3447. DOI:10.1109/JLT.2012.2215307 · 2.97 Impact Factor
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    • "Among various approaches, polarization-division-multiplexing (PDM) is one of the enabling techniques that can double the system capacity directly by carrying two data channels on orthogonal polarization states but at the same wavelength [2], [3], and over the past few years, numerous PDM-based hero experiments have been demonstrated [4]–[6]. On the other hand, all-optical regeneration is a potential enabler for future all-optical networks [7]–[25], as it may simplify the network configuration without complicated and bit-rate dependent optical-electrical-optical (O-E-O) conversion. Many schemes of all-optical regeneration have been demonstrated based on different nonlinear mechanisms and different nonlinear media for various modulation formats. "
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    ABSTRACT: Schemes of all-optical regeneration in polarization-division-multiplexing (PDM) systems are proposed and demonstrated with 2 × 10-Gb/s return-to-zero on-off-keying (RZ-OOK) transmission. Regeneration is achieved based on self-phase-modulation (SPM) effect and detuned filtering in highly nonlinear fiber (HNLF) with a polarization-diversified loop configuration. Furthermore, the ability of mitigating polarization-mode-dispersion (PMD) effects in PDM systems is evaluated. More than 3.7-dB eye-diagram-based signal-to-noise-ratio (SNR) improvement is achieved in the presence of 6.3-ps PMD as the pulsewidth of the PDM signal is about 18 ps.
    IEEE Photonics Journal 09/2011; 3(4-3):703 - 712. DOI:10.1109/JPHOT.2011.2160937 · 2.21 Impact Factor
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    • "Since the gain in a PSA exhibits symmetry with respect to π phase shifts of the signal, direct processing (amplification and regeneration) of two-level PSK signals [binary phase shift keying (BPSK) or differential phaseshift keying (DPSK)] is possible [46]. The initial proposal of DPSK regeneration through the use of PSA [46] was followed by demonstrations of phase regeneration [47] and simultaneous phase-and-amplitude regeneration [48] of return-to-zero (RZ)- DPSK signals using a PSA based on a Sagnac interferometer. Following the identification of the FWM-based schemes in [35], phase regeneration [49] and simultaneous phase-and-amplitude regeneration [50] for nonreturn-to-zero (NRZ) DPSK signals were demonstrated through the use of degenerate FWM. "
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    ABSTRACT: Phase-sensitive amplifiers (PSAs) offer numerous advantages over phase-insensitive amplifiers in optical communications. Squeezing of optical phase through PSA can remove accumulated phase jitter, which is a critical functionality for an all- optical, phase-shift keyed network. In recent experiments, reviewed in this report, different implementations of PSA were used for phase regeneration of both return-to-zero differential phase-shift keying and nonreturn-to-zero differential phase-shift keying data. The first demonstration explored the properties and performance of PSA that occurs in nonlinear interferometers. Experiments confirmed that a PSA operating in the depleted pump regime provides simultaneous reduction of amplitude and phase noise (PN). Phase regeneration performance limit was reached as a consequence of pump-wave imperfections, which can be significantly reduced through proper design. PSA that occurs directly in fiber in a traveling-wave configuration through partially degenerate four-wave mixing was also studied. The latter implementation offers stronger phase-matched gain and suppression of amplitude-to-phase noise conversion. Technical issues that remain to be addressed are identified for each implementation. Results characterized using coherent detection offer direct measurements of the phase-regenerative behavior.
    IEEE Journal of Selected Topics in Quantum Electronics 06/2008; 14(3-14):648 - 658. DOI:10.1109/JSTQE.2007.915397 · 2.83 Impact Factor
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