High-efficiency Coupling Structure Based On Silicon-based Multi-channel Arrayed Waveguide Grating

In recent years,with the rapid increase of data volume in optical communication network systems,the demand for high-speed optical devices has increased significantly.And higher requirements have also been put forward for their performance.As the key device in the optical transceiver system,arrayed waveguide grating can achieve many advantages such as system integration,low power consumption and miniaturization.However,the development of integration is inevitably accompanied by miniaturization,which will bring about the mode field mismatch between integrated devices and increase insertion loss.Thus,affecting the performance of the whole optical transceiver system.Therefore,we designed the arrayed waveguide grating(AWG)to realize the multiplexing and demultiplexing of 1271/1291/1311/1331nm wavelengths.And we designed the waveguide coupling structure of lasers and semiconductor detectors.We modified the iterative optimization of simulation model to achieve low coupling loss and high transmission efficiency optical transceiver.In this paper,we firstly analyzed the related optical waveguide theory of AWG,including the structure and mode of slab waveguides and rectangular waveguides.By analyzing the working principles and performance index of AWG,we summarized the design idea.We designed AWG based on parabolic transition waveguides,transverse transition waveguides,and auxiliary waveguides.Therefore,the optical field from the input/output/arrayed waveguides to the slab waveguides is a smooth transition process,which could reduce the mode field mismatch.For example,the transverse transition waveguides can effectively reduce the insertion loss from 3.46dB to 1.76dB,the crosstalk of adjacent channels by about 2.3dB and improve the 3dB bandwidth by about 1.3nm.We also mainly studied the coupling structure based on planar optical waveguide technology.We analyzed the theoretical principle and related loss of end-coupling of waveguides.In order to couple with semiconductor lasers and waveguide photodetectors,we designed the hybrid multi-core waveguide coupling structure,multi-core conversion coupling structure and the double-step spot-size converter.By analyzing the structure and size of the different materials waveguides and the transition mode of the tapered waveguides,the effective refractive index changed more slowly.Thus,we reduced the conversion loss between different waveguides and realized the mode field matching between different devices.And we improved the coupling efficiency of the whole coupling structure to over 80%.