Research Of All-Optical 2R Regeneration Based On Microstructured Fiber

These research works of this dissertation are supportted by National Basic Research Program of China (No.2003CB314906) , the Key Grant Project of Chinese Ministry of Education (No.104046) and Co-Constructed Project of Beijing Education Committee (No.XK1001 30437) .Microstructured fiber (MF) commonly consists of a fused silica core surrounded by an array of air holes running along the fiber length. It has many unusual properties compared to conventional optical fiber, such as endless single mode propagation, flexible tailorability of dispersion, high birefringence etc. Therefore MF has already found important applications in nonlinear fiber optics, optical communication and many other fields.In this thesis, the feasibility of MF in all-optical 2R regeneration is discussed and some important results have been achieved. The main achievements are listed as follows:1．Theoretical study(1) The feasibility of MF in all-optical 2R regeneration is discussed and SPM-based all-optical 2R regeneration is studied in detail. The simulation results show that this scheme has many advantages.(2) The effect of fiber parameters on SPM-based all-optical 2R regeneration performace is investigated.All-optical 2R regeneration can be realized by using a microstructured fiber with normal dispersion or a microstructured fiber with anomalous dispersion. But fiber dispersion has great influence on the regenerator performance. A mount of normal dispersion decreases the oscillatory structure in the broadened spectra and a better regenerator transfer function is achieved.(3) An improved scheme of optical regeneration by using two-stage regenerator is proposed in order to solve the problem of wavelength conversion caused by the SPM-based all-optical 2R regeneration. Results show that the performance characteristics of the two-stage regenerator are even better than that of single-stage one.(4) The effect of filter parameters on SPM-based all-optical 2R regeneration performace is investigated.The filter parameters have much influence on optical regeneration. In order to achieve optical regeneration, filter center wavelength and filter bandwidth need to meet certain requirement. By optimizing those parameters, a better regeneration result can be obtained.(5) The transmission characteristics of Nonlinear Optical Loop Mirror (NOLM) are studied. The effect of fiber parameters on the transmission performance is discussed. And application of NOLM in all-optical 2R regeneration is discussed.2．Experimental studyExperimental study of all-optical regeneration using a combination of self-phase modulation (SPM) effects and offset filtering in microstructured fiber is presented. An 80m-long microstructured fiber with dispersion of 0．6ps/nm/km and nonlinearity ofγ=11Wkm at 1550nm is used as the nonlinear medium. The dispersion is about-0．58 ps·nm·km at 1550nm, and it varies less than 1．5ps·nm·km between 1500 and 1650nm. By adjusting the input power into the microstructured fiber and the parameters of the tunable filter, all-optical 2R regeneration is achieved. The results show that transmission characteristics match well the theoretical analysis.