Research On All-Optical Multilevel Amplitude Regeneration Technology

With the development of fiber optic communication,the traditional optical repeater based on optical-electrical-optical conversion has been unable to satisfy the needs of higher-speed information processing.All-optical regeneration technology has become one of the key research directions of information processing.In particular,all-optical regeneration in a high-order modulation format represented by PAM?pulse amplitude modulation?and QAM?quadrature amplitude modulation?is attracting attention.This thesis mainly studies the all-optical PAM signal regeneration technology,and proposes a cascaded Mach-Zehnder interferometer?MZI?and reflective MZI schemes,and analyzes the integration of all-optical PAM regenerators.The main work content and innovation of the thesis are as follows:1.The multi-level regeneration characteristics of single-stage MZI structure are summarized.The influence of structural parameters on regeneration performance is analyzed.The regeneration parameters of single-stage MZI structure are optimized by the minimum value method.On this basis,a cascaded MZI all-optical PAM regenerator scheme is proposed,and the power matching relationship between the two stages is studied.By optimizing the length of the second-order highly nonlinear fiber,the regenerative performance which is much better than the single-stage MZI structure is obtained.2.A new all-optical PAM regeneration scheme based on reflective MZI is proposed.The effect of cross-phase modulation on the regenerative performance is compensated by a non-reciprocal phase shifter.The method for determining the regenerable working level range and working point is given.Compared with the single-stage MZI structure,the all-optical PAM regeneration scheme based on reflective MZI has a higher signal-to-noise ratio improvement,which is 3.28 dB higher than the single-stage MZI structure.Studies have shown that when the signal-to-noise ratio of the PAM signal is greater than 20 dB,the all-optical regenerator can realize error-free transmission processing.3.The integration of all-optical PAM regenerator was studied.The influence of two photon absorption?TPA?effect on power transfer function?PTF?in silicon waveguide materials was analyzed.For the two regeneration principles of self-phase modulation?SPM?and cross-phase modulation?XPM?,the limitation of the TPA effect on the amplitude and nonlinear phase shift of the guided wave field is discussed.The analysis of several optional optical waveguide materials shows that theSi₇ N₃ materials are integrated and the corresponding integration scheme is simulated.