Passive Multi-wavelength Optical Antenna Design And Simulation

Various applications of communication, detection, reconnaissance, surveillance, tracking and pointing between moving targets, are usually processed in the microwave and infrared bands. As the need for communication rate,capacity, secrecy and the all-weather and high-performance detection and tracking systems increases quickly, the communication, detection and tracking techniques in the near-infrared and visible light region were strongly investigated and developed. At the beginning of the 21st Century, overseas researches have already presented satisfactory achievements. Not only in the laser mobile communication systems, but also in the Lidar and directed high-energy laser weapon systems, precise tracking subsystem is the very important building block. And the stability of the line of sight (SLOS) is the key for tracking subsystem to reach high performances.This thesis aims at the full-waveband optical system of the up-to-date improvements in the application scenarios of the based on the theoretical, simulative and some applied researches. In this thesis, an active/passive multi-wavelength optical antenna of all-weather and high-performance detection and tracking systems are studied. It could be provide theoretic fundamental theories and experiential evidences for the realization of the full-waveband optical system in the communication, detection, reconnaissance, surveillance, tracking and pointing technologies among moving targets which suffers from atmospheric random channel effects, as well as the common bottleneck technology in the optical frequency systems for our nation.Firstly, the work principle of optical antenna is introduced, and the basic demands of the optical system design are analysised, infrared optical material plating membrane have been selected. And then Original structures are deduced.Secondly, basic design project of active/passive multi-wavelength optical antenna is proposed after the optical gain of Cassegrain telescope has been analyzed, the optical gain is up to 108.16dB with FOV of 2°.The high precision optical antenna structure is solved through gauss optics and primary aberration principle, and the aberration is optimized and analyzed by CODE V. The objective of the pre-collimation lens and Cassegrain telescope is designed to provide accurate pointing of a diffraction-limited and high quality beam, as would be required for a longer range tracking link.An optical isolation technical approach has been studied, trans-receive optical power isolation with single detector and multi-wavelength isolation with multi-detectors structure was designed, and proves that the design of active/passive multi-wavelength optical antenna is feasible. Then the structure of optical antenna is optimized and analyzed with optical design software CODE V.Two kinds of design project are proposed: the "windowed" read mode CCD project and adaptive optics subsystem project.In the "windowed" read mode CCD project, Spatial acquisition and tracking for the moving targets is accomplished using a large format CCD array. A small portion of the transmit laser beam is reimaged onto the array focal plane. The echo signal reflect from a remote moving target is received and imaged onto the same array focal plane. By reading out the area of the detector containing the echo signal and calculating the image centroid, the both coarse pointing and precise tracking are accomplished.The adaptive optics subsystem capable of minimizing the impact of atmospherically induced tiptilt and defocus distortions of the wavefronts and precisely tracking an mobile target is presented. To reduce the size of the optical antenna, a polarizing beam splitter cube is used in the adaptive optics subsystem to fold the optical path into a compact space.