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Research On Phase Sensitive Amplifiers In The Application Of All Optical Regeneration And Multicasting Of QPSK Signal

Posted on:2016-11-14Degree:MasterType:Thesis
Country:ChinaCandidate:J Z LianFull Text:PDF
GTID:2348330479953144Subject:Optical Engineering
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In the Internet-based information age, multimedia application has increased rapidly. The increasing demand for transmission capacity has brought enormous pressure and challenges for current optical fiber transmission systems. The digital coherent optical communications have rebirthed recently. Advanced modulation formats have been regarded as an essential technique to achieve ultra-high speed ultra-large capacity ultra-long distance fiber optical communications. Moreover, wavelength multicasting is a key technology in optical network due to its flexibility. Therefore the wavelength multicasting scheme with the capability of all-optical regeneration for advanced modulation formats has attracted more and more attentions. In this dissertation, we propose all-optical one-to-three wavelength multicasting of quadrature phase shift keying(QPSK) signal with capability of phase regeneration, using dual-conjugated-pump phase sensitive amplification(PSA). We further theoretically analyze the operation principle and optimize the parameters for the best regeneration and wavelength multicasting performance. The main contents are included as follows:(1) Based on comprehensive literatures review, we overview and classify the existing schemes on signal regeneration of advanced modulation formats and wavelength multicasting and focus on the PSA-based all-optical regeneration configuration and cascaded four wave mixing(FWM)-based multicasting scheme. We also compare the advantage and disadvantage of different schemes.(2) The FWM effect in fiber, including the gain and phase response is illustrated. The electric field of signal after fiber transmission is deduced. The parametric gain of signal in different conditions of phase matching is discussed in details. We also discuss the characteristics of FWM effect on the condition of phase matching.(3) Two different kinds of PSA model are introduced: 1-mode degenerate idler PSA and 2-mode degenerate pump PSA. Corresponding to two kind PSA models, we derive the transfer functions of both signal and idler, respectively.(4) Based on 1-mode degenerate idler PSA, we proposed all-optical phase regeneration and one-to-three wavelength multicasting scheme, using dual-conjugated-pump PSA. The seven-wave coupled equations are used to investigate the characteristics of signal and multicasting copies. It is found that the nonlinear phase shift has impact on the transfer function of signal while its impact on two copies' transfer function is negligible. We also find a squeezing center deviation between input signal and two copies. There exists an optimal input phase of signal to realize simultaneous phase regeneration for three multicasting channels. Finally, the influence of gain saturation effect on the proposed scheme is investigated.(5) We build QPSK signal transmitter and coherent receiver system using VPItransmission maker9.0 and perform dynamic simulations to evaluate the scheme of QPSK multicasting with capability of phase regeneration. The simulation results agree well with the seven-wave model analytical results, which confirmed the validity of the seven-wave model. The best regeneration performance of three multicasting channels can be achieved by tuning the nonlinear phase shift and input phase of signal. In particular, on the condition of the optimum nonlinear phase shift and input phase, the EVM after regeneration can be decreased by 33%, and the BER curves verify that the OSNR penalties of three multicasting channels can be improved by around 1dB at BER = 10-3. Those results show that the proposed all-optical phase regeneration and multicasting scheme can squeeze the phase noise efficiently and create multiple channels for optical network.
Keywords/Search Tags:Quadrature phase shift keying(QPSK), All-optical signal regeneration, Wavelength multicasting, Phase sensitive amplification
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