Design And Optimization Of Broad-Band Arrayed Waveguide Gratings For Microspectrometer

With the continuous development of science and technology,spectrometer has extensive applications in biosensing,food safety,environmental monitoring and other fields.Conventional spectrometers bring a lot of inconvenience to practical applications due to their large size,heavy mass and high cost.In order to meet the requirements of portability and stability,on-chip spectrometers have become the new trend.In this papaer,the design and optimization of a broad-band arrayed waveguide grating(AWG)for microspectormeter are studied.The main contents include:1.Design and simulation of a broad-band arrayed waveguide grating: Based on the analysis of the working principle of AWG,the 20-channel broad-band arrayed waveguide grating operating in the wavelength range of 590 nm to 780 nm is designed.According to the proposed design flow the S-shaped anti-symmetric AWG layout is generated and the simulation of AWG is carried out.2.Optimized design solutions for reducing the size of AWG:The geometrical layout of S-type antisymmetric AWG is analyzed in detail and the caculation formula of the AWG device size is derived.The influence of structural parameters on bending radius and dimensions is discussed.For the constrained optimization problem,a penalty function approach is used to construct a computational model for the dynamics of the penalty function factor with the number of population iteration steps.By introducing the idea of differential evolutionary algorithm and the elimination mechanism of the worst individuals in a population,an improved particle swarm algorithm is proposed to optimally reduce the size of AWG devices,which overcomes the problem that the original particle swarm algorithm easily falls into local extremes and improves the global optimization capability of the algorithm.By applying this method,a broad-band AWG device is optimally designed.The results verify the effectiveness of the design.3.Preparation and characterisation of the borad-band arrayed waveguide grating:The broad-band AWG chip is prepared according to the process flow,and the test platform is built for testing the performance of the prepared AWG.The test results show that the central wavelength of the device is 681 nm,the wavelength interval is 10 nm,the insertion loss from the central channel to the edge channel of the chip is-2.76 dB to-6.93 dB,the insertion loss uniformity is 4.15 dB.