Submitted In Total Fullment Of The Requirements For The Degree Of Master In Optical Engineering

For the structure limit of traditional wavelength scanning systems based on screwmandrel and step motor, they cannot simultaneously work both accurately and quickly.Three new meatheads to improve the performance of classical wavelength scanningsystem are proposed in this paper.By the research on the step motor directly driven system, it is found that it spendsless time to scan a whole spectrum, but the step motor runs unsteadily in high subdivi-sion mode, which will decrease the system's wavelength accuracy. After studying theperformance of step motor and harmonic motor, a harmonic motor driven scanningsystem is designed. As the step motor, the harmonic motor has better performanceon accuracy and stability. Test result shows that this system's wavelength accuracyreaches±0.4nm while the repeatability is±0.5nm.In order to increase the system's accuracy, a feed back structure is needed. Soa Moire fringe technique used system is designed, it is supposed to feed back thescanning performance of the gating. The gating is driven by a slider on a stem whichis driven by a step motor. The gating scanning performance can be detect accuratelyfor the Moire fringe sensor has the ability to detect small move. Test result shows thatthe wavelength accuracy is±0.15nm, and the repeatability is±0.15nmThe Moire fringe used system has a good performance on the wavelength accu-racy, though the cost of it is so high. In order to decrease the system's cost, a newactive opto-electrical feed-back measurement system based on laser, PSD and mul-tilateral prism mirror is designed. The purpose of the new strategy is to make thewavelength scanning system work not only accurately but also quickly. Elementaryexperiments show that the wavelength accuracy of it reaches±0.20nm, the repeata-bility is less than 0.20nm, and it can manages a whole spectrum in 20 seconds. The Moire fringe based system and the multilateral prism mirror system has thegood performance among all and the multilateral prism mirror system is much cheaperthan the former one. The paper offers some new thinking and meatheads for the re-search and improvement of the high accuracy wavelength scanning system.