Research On All-optical Regeneration Based On Magneto-optical Four Wave Mixing

Nonlinear effect in the fiber is able to realize ultrafast optically controlled all-optical signal processing, which will play an increasing important role in the future all-optical network. Among those technologies, all-optical 2R/3R regeneration based on fiber four-wave mixing(FWM) has attracted numerous attentions. Combining magnetic-optical effect with nonlinear effect, we can not only improve the performance of all-optical regenerators, but also achieve magnetically-controlled intelligent fiber information processing. In this thesis, on the basis of the Magnetic-optical FWM(MOFWM) theory, the influence of magnetic-optical effect on power transfer function(PTF) of all-optical regenerators is investigated both experimentally and theoretically, and the equalization method of quasi-phase-matching for multi-wavelength regeneration of time-interleaved signals is also presented. The main innovation contents are as follows:1. MOFWM coupled-mode equations for guided optical pulses in the fiber are proposed, which involves a series of physical effects including pump consumption, group velocity dispersion(GVD), self-phase modulation(SPM), cross-phase modulation(XPM), FWM and Magnetic-optical effect. Furthermore, degenerated MOFWM is numerically solved with split-step Fourier method(SSFM). The calculation results agree well with the OptiSystem simulation.2. An assessment method of PTF of all-optical regeneration is presented. The theoretical calculation is verified by the MOFWM regeneration experiment, and the influence of magnetic field on the performance of data-pump FWM regeneration is explored experimentally. It is shown that, under appropriately biased magnetic field, the extinction ratio performance of the fiber-based regenerators is improved, and the magnetic field dependency of the output idler power is the most sensitive for the case with orthogonal SOPs. In addition, employing the characteristics of MOFWM for circularly polarized input lights, a method based on magnetic-optical nonlinear theory is proposed for measuring Verdet constant of highly nonlinear fiber(HNLF).3. An equalization method based on FWM quasi-phase-matching is proposed, and uniform regeneration is obtained for time-interleaved signals theoretically. Starting from optimizing the phase-mismatch factors of degenerate FWM, the equalization and regeneration of fixed or arbitrary four wavelengths are realized by the optimization of wavelength distribution or the fiber parameters, respectively. Our calculations show that the variations of output peak power, ER and Q for the equalized channels are less than 0.25 dB, 0.42 d B and 1.5, respectively. Moreover, it is found that optimizing the fiber length is able to improve applicability of quasi-phase-matching method.4. From the aspects of crosstalk and uniformity of regeneration performance, the influence of magnetic field on FWM-based all-optical regeneration of time-interleaved signals is analyzed theoretically. The study reveals that, under approximate conditions, magnetic field can not only improve the uniformity of multi-wavelength regeneration(especially the power equalization), but also reduce the inter-channel crosstalk which allows the transmission of time-interleaved signals with larger duty cycles.