Study On Beam Pointing Control Method For Phased Array Of Optical Waveguides

Although the traditional mechanical scanner has the advantages of large scanning angle and small optical loss,it is difficult to meet the actual requirements in the future military field because of its disadvantages such as complex structure,heavy weight,slow scanning speed and large inertia.The optical phased array has the advantages of precision and stability,fast scanning speed,no inertia,and arbitrary setting of the scanning direction.Optical waveguide materials have become the research frontier of optical phased array devices in recent years due to lower driving voltage,larger beam scanning range,and shorter response time than other phased array fabrication materials.In order to improve the scanning performance of optical waveguide phased array,and effectively control the deflection of incident light.First,the structure of phased array is presented.The far-field intensity distribution of phased array is deduced from grating diffraction theory,and the scanning principle of optical phased array is explained.Based on the finite difference method for solving the electromagnetic properties in the anisotropic media the field characteristics of anisotropic dielectric waveguide array are showed and the calculation of the Rayleigh scattering properties for an anisotropic media target are developed.With the help of Matlab,the genetic algorithm is used to optimize the grating lobes by monotonically increasing and random distribution.However,genetic algorithms are easily trapped in local extreme traps,resulting in unsatisfactory results.Then redesigned a hybrid genetic-particle swarm optimization algorithm to optimize the spacing between array elements to achieve better grating lobe compression.Finally,the output waveform optimization is an important part of the beam-pointing control theory.After the incident light is deflected,the quality of the output beam is an important indicator to measure the quality of the beam-pointing control.The suppression effect of grating lobes directly determines the quality of the output beam.Therefore,theoretically,we first prove that the phase weight can weaken the grating lobe with uniform distribution of the array elements.Then the particle swarm optimization algorithm is used to optimize the additional phase of the array element.All the simulation results show that irregular array spacing and phase weighting can effectively suppress the grating lobes and improve the effect of beam deflection control.