Study On The Optical Feedback System And Phase Correction

Optical two-dimensional iterative function system is the combination of optical information processing and fractal, chaos. It integrates some advantages such as parallelism, ultra-high speed and so on. The 4f system is an important optical path for the realization of optical two-dimensional iterative function system. Research on the characteristics of the 4f system is the basis for improving the initial input quality of iterative function system. This paper takes optical two-dimensional iterative function system as the research object, it analyzes and researches characteristics of the 4f system and the method which improves the initial input of iterative function system, it includes several parts.1. Three kinds of optical feedback systems were studied and compared, then the coherent optical feedback system was selected to accomplish optical two-dimensional iterative function system, meanwhile, the 4f system is the basis of coherent optical feedback system.2. In this thesis, the model of coherent optical feedback system was established and the model is the basis of the 4f system simulation. According to the analysis simulation results, some characteristics of optical iterative function system were obtained. A certain improvement of bandwidth and output quality can be achieved by using optical iterative function system. The increased ranges of bandwidth and output quality were dependent of initial feedback input.3. In order to improve figure quality of feedback input, this paper analyzed errors which impact on the 4f system output. A variety of error sources were discussed and the methods of reducing errors were elaborated. This paper drew a conclusion that aberration and phase perturbation have great influence on the 4f system output by simulation of the 4f system.4. Aberration and phase perturbation decreased by using method of modulation phase in adaptive optics. Three kinds of wavefront sensing technologies were studied and compared, then the Hartmann-Shack wavefront sensing technology was selected for system simulation. The models of Hartmann-Shack wavefront sensor and phase spatial light modulation were established. The wavefront phase representation by using Zernike polynomial, wavefront sensing, wavefront reconstruction and wavefront phase correction of the system were simulated and the results were analyzed. In this paper, one of innovative points is that a method which improved the initial input of iterative function system has been proposed. Aberration and the phase perturbation were reduced by means of modulation phase to improve input of iterative function system. Another one is that a method improving image quality by iterative extrapolation. Diameters of optical devices are limited lead to loss of high-frequency information. The method is that iterative extrapolation widen spectrum of image to improve quality of image.Through the literature reference, the theoretical analysis and the theoretical simulations, some researches are done on the characteristics of optical iterative function systems and the wavefront phase modulation method for improving the initial input of the iterative function system in this paper. This has lay the foundation for further improving the initial input of the iterative function system and realization of the optical iterative function system ultimately.