Study On The Method Of Side Lobe Suppression With Optical Wave-guide Phased Array

As a new type of laser scanning technology,the optical waveguide phased array has the characteristics of wide range,fast scanning speed,high resolution and low control voltage and has found an increasingly wide utilization in many military and civilian fields,such as imaging,radar,optical switch and printing.Due to the limitation of the current processing technology,there are some problems of the structural parameter error of the phased array of optical waveguides and the inconsistency of the element materials.Meanwhile,the optical waveguide phased array is also affected by the error of the incident light source and driving voltage,so that the optical waveguide phased array will generate side lobe in the scanning process,reducing the quality of the beam scanning.Therefore,the study of the side lobe compression method for optical phased array of optical waveguides plays a very important role for its practical application.Based on the basic theory of the optical waveguide array electro-optic scanner,with the electro-optic effect of optical waveguide crystal material and its grating diffraction principle as the theoretical basis,the beam pointing,lobe width and beam zero of one-dimensional optical waveguide optical phased array are studied.According to the principle of side lobe suppression,the position of side lobe,the level of side lobe and the conditions of grating lobes are analyzed.According to the formula of light intensity distribution,the influence of system parameters(element number and element spacing)on the far-field diffraction intensity distribution of optical waveguide phased array is analyzed.The side lobe compression method of the optical waveguide optical phased array is studied.In view of the side lobe suppression,the amplitude weighting side lobe suppression is studied.For the grating lobe suppression,the density and phase weighting gratin globe methods are studied.Based on this,for the hybrid optimization of side lobe and grating lobes,a hybrid weighted optimization algorithm based on the combination of amplitude weighting and phase weighting is proposed.Based on the combination of the illumination function of different amplitudes and the step coefficient of phase weighting,the effect of mixing weight on the side lobe compression and the main beam width is studied.Genetic algorithm is used to improve the basic hybrid weighting method,and experimental results show that the mixed weighting method based on genetic algorithm can further compress the side lobe,and the main lobe width has not increased significantly.