Wavelength-shift-free all-optical 2R regeneration via four-wave mixing
ABSTRACT A wavelength-shift-free all-optical FWM-fiber-based 2R regenerator was proposed and tested by simulations. By comparing the input and output Q-factors, we found a new and improved optical regeneration regime that manifests itself when signal depletion occurs.
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ABSTRACT: A new scheme for all-optical signal reshaping is proposed. It is shown that proper adjustment of the operating conditions of a wavelength converter based on four-wave mixing (FWM) in dispersion-shifted fiber (DSF) results in significant extinction ratio enhancement and noise suppression of the converted signal. The key issue in the proposed idea is the application of the modulation bitstream on the input pump wave. Detailed numerical simulation shows that it is possible to achieve a wavelength-converted output with extinction ratio of 20 dB when the extinction ratio of the input signal is 10.5 dB, while at the same time, the improvement in the Q-factor is almost 6 (from 6.5 at the input, it becomes more than 12 at the output). The theoretical predictions have been experimentally confirmed by measuring the transfer function of the FWM in a 17-km-long DSF under different operating conditions. The obtained results are in a very good agreement with those predicted theoretically.Journal of Lightwave Technology 10/2003; 21(9):1892- 1902. · 2.56 Impact Factor
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ABSTRACT: It is experimentally demonstrated that the four-wave mixing (FWM) effect in an optical fiber can be exploited to achieve all-optical reshaping. The injection of a signal and a strong continuous-wave (CW) pump into a common dispersion-shifted fiber results in several wavelength-converted replicas of the signal. These spectral components exhibit various reshaping behaviors. Selecting low-order FWM waves, we observe a sinusoidal-like transfer function. However, unlike other reshaping devices, a step-like transfer function is obtained for higher order mixing products. A significant noise compression is observed at the converted output, starting from an input noisy nonreturn-to-zero (NRZ) signal stream.IEEE Photonics Technology Letters 03/2001; · 2.04 Impact Factor
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ABSTRACT: We show both theoretically and experimentally that signal re-amplifying and reshaping (2R) optical regenerator based on self-phase-modulation (SPM)-induced spectral broadening followed by optical filtering has significant advantages over conventional 2R regenerators. By discriminating amplified spontaneous emission noise from a pulsed signal, the SPM-based regenerator is able to selectively attenuate noise more than the pulsed signal. This unique feature results in a direct improvement in bit-error ratio (BER) of a noisy pulsed signal, whereas conventional 2R regenerators can only prevent BER degradation-not actually improve it. We compare the two classes of regenerator and highlight their fundamental differences. We also demonstrate the BER improvement of a noisy signal filtered with an SPM-based regenerator that utilizes a highly nonlinear silica fiber, and present a compact version by exploiting a short length of As<sub>2</sub>Se<sub>3</sub> chalcogenide glass fiberIEEE Journal of Selected Topics in Quantum Electronics 08/2006; · 4.08 Impact Factor