Study Of Interleaver Based On Ring Resonator Assisted Mach-Zehnder Interferometer

Interleaver is one of the most important components in optical communication system, which is vigorously developing recently. The filter, which had been successfully applied in current optical communication system, cannot adapt to current upgrading need. The traditional filtering technology has reached its bottleneck. Therefore, it is necessary to find new ways to meet the upgrading and expansion demands and avoid high cost to replace the existing equipments. Now, to develop a novel low-cost Interferometer is becoming one of the key issues in the field of optical communication systems.Based on the theory of novel ring resonator assisted Mach-Zehnder interferometer, this paper analyses the characteristics of single-ring resonator assisted Mach-Zehnder interferometer and designed some related experiments. The main results and innovations are as follows.1. The current technology of Interleaver was described. And the advantages, disadvantages and principles of several Interleavers were analyzed and compared with each other.2. The relation between the bandwidth allocation of odd-even ports and ring circumference (Lr) on length difference (ΔL) of MZI arms was analyzed, which leads to the conclusion that the ring circumference (Lr) on length difference (ΔL) of MZI arms can be used to adjust bandwidth allocation of ring resonator assisted Mach-Zehnder interferometer. The result shows that a novel interleaver with 1:2 asymmetric bandwidth allocation can be achieved by adjusting Lr/ΔL=0.5 and that with 1:1 symmetry bandwidth allocation can be achieved by adjusting Lr/ΔL=2.3. The distribution feature of optical power was analyzed by utilizing the step-index fiber mode field theory. And the optimal radius of optical fiber microwires which can be used to product microring resonator was attained by combining the theoretical results of the relation between limiting factor for power and fiber circumference.4. Characteristics of the lateral coupling function between micro-ring and straight waveguide were analyzed by utilizing the coupling function and transfer matrix method, which gives rise to the obtaining of the inter-influence between the micro-ring bend radius and coupling distance on coupling coefficient and the amplitude coupling ratio, and the inter-influence between the coupling coefficient and microring assisted Mach-Zehnder interferometer output. The optimal value of the coupling angle was obtained.5. The precisely controlled fused elongation device platform was set up, which leads to the realization of the microring resonator with various radius of microwires. The influence of the bend radius and the external environment on the transmission loss was attained with the measurement of optical fiber microwires transmission loss under various circumstances. After several experiments, fiber microring resonator with about 1mm radius, high extinction ratio(>12dB) and good resonance were gained.