Research On Key Techniques Of Interferometric Imaging Based On Photonics Integrated Devices

Photon integrated interference imaging is based on the principle of optical interference imaging and combined with integrated photonics technology.Photon integrated interference imaging combined with interference imaging and photonics technology can reduce the system volume,weight and power consumption to 1/10 ? 1/100 of the original.The photonic integrated interference imaging system provides a payload of high resolution,small size,light weight and low power consumption for future space optical systems.This provides a high-resolution,low-cost option for space surveillance missions based on carrying payloads and Cube Sat designs.This new imaging method can be extended to many fields such as space exploration,remote sensing and hyperspectral,and has important application value.At the same time,it can provide corresponding technical support for future space-based long-baseline interference imaging telescopes.In this paper,the photonic integrated interference imaging technology is introduced,and the important problems in it are analyzed and studied.Starting from the basic principle introduction and imaging model,the main research contents are as follows:1.Theoretical modeling of photonic integrated interference imaging.In this paper,starting from scalar diffraction theory,the optical imaging process of far-field incoherent radiation sources is discussed,and the relationship between the resolution of interference imaging and the baseline length of the observation wavelength is analyzed.Fizeau-type interferometric imaging,Michelson-type interferometric imaging and photon integrated interferometric imaging are discussed.Combined with the hardware characteristics of the photonic integrated interference system,the coupling efficiency between the light spot focused by the lenslet and the on-chip waveguide is analyzed,and the apodization effect of the system and the field of view of the imaging system are analyzed.On this basis,the relational expressions between the optical traditional function and point spread function of the system and the observation wavelength and baseline are deduced.2.Based on the idea of time-division sampling,the aperture arrangement scheme of the ultra-large aperture interferometric imaging system is designed.According to the existing arrangement of lens arrays and baseline pairing schemes,the baseline pairing and collecting lens arrangement principles in the system are summarized.On this basis,three design schemes of ultra-large aperture interference imaging systems are proposed to provide observation schemes for high-precision astronomical observations.In addition,the main optical processing modules on the photonic integrated chip are introduced,and the solution of the visibility signal and its calibration scheme,as well as the influence of the visibility measurement error on the final imaging quality are analyzed.3.Aiming at the inverse solution of the ill-conditioned matrix for photon integrated interference imaging image reconstruction,an revised entropy algorithm is proposed to enhance the image reconstruction effect.In this paper,the astronomical synthetic aperture image reconstruction algorithm is refered,and the theoretical framework of image reconstruction is proposed,and the simulation verification of various image reconstruction algorithms is given under this framework.It is revealed that the highfrequency sampling sparseness of the existing photonic integrated interference imaging causes the Gibbs ringing artifact in the IFFT restored image.Therefore,an revised entropy prior function is proposed.Based on this prior,an improved entropy reconstruction algorithm is proposed.Simulation verifies the feasibility of the revised entropy algorithm to eliminate ringing artifacts.4.A sparse-aperture photonics-integrated interferometer(SPIN)imaging system is proposed,and its imaging effect is analyzed and simulated.Aiming at the problem that the existing Michelson-type photonic integrated interference imaging system requires a large number of lens arrays and multiple narrow-band observations,a sparse-aperture photonics-integrated interferometer(SPIN)imaging system is proposed.The SPIN system is a Fizeau-type photonic integrated interference imaging system.The main obstacle to this type of imaging transition is to eliminate the coupling limitation of the waveguide tip,namely the apodization effect.This effect is caused by the Fourier lens and waveguide coupling effect,preventing the SPIN imaging system from achieving higher resolution.This apodization effect can be eliminated by magnifying the lens spot with a microscope.In addition,using the waveguide array to receive the fine details of the observed target can also expand the field of view of the system.The coupling efficiency of the waveguides and the crosstalk error between the arrayed waveguides are analyzed,which are of great significance to the parameter setting of the SPIN imaging system.On this basis,the imaging principle is deduced,and an image restoration algorithm based on hyper-Laplacian is proposed.By simulating the SPIN imaging system with 7 sub-apertures and 1 waveband,it is proved that the imaging system has high imaging quality and greatly reduces the ringing effect in image.5.The principle verification experiment of photonics integerated interference imaging based on silicon-based photonics device was carried out.In terms of chip design,the surface grating structure replaces the original straight waveguide,which can greatly reduce the difficulty of spatial optical coupling.In addition,three on-chip structures for quadrature detection of signal light are designed and tested.The test results show that the 4×4 MMI structure has the best splitting ratio and phase modulation accuracy.Based on 4×4 MMI,an experimental platform for optical interference imaging principle verification was built,and the visibility signal of a specific target was measured.By testing and analyzing the photonic chip and measuring the visibility signal,the principle of photonic integrated interference imaging is verified,and the image processing algorithm and arrangement of lens array scheme are partially verified Based on the above-mentioned key research contents,this paper expounds the overall structure of photonic integrated interference imaging technology and the solution to key problems,which provides theoretical and technical support for the practical research of this technology,and also provides basis and new ideas for the development of new large-aperture and high-resolution imaging technology.At the same time,it can provide corresponding technical support for future space-based long-baseline interference imaging telescopes.