Intelligent High Extinction Ratio Test Technology Research

"The research of Intellectualized high extinction ratio measurement system" mainly carries on to design a photosource for the high extinction ratio measurement system, and to seek an effective way to elimination photosource fluctuation. And then union the designed photosource and the advanced computer technology to establish a set of intellectualized high extinction ratio measurement system ,which test speeds quickly, data processing , gathering, and the operation automation ,and also the data processing is accurate and stability.The extinction ratio is an important optic polarization technology parameter of material and optic component, is one of the main physical parameters of each kind of polarization component, crystal and each kind of optics function material, and laser matter nature, and also is the main technical specification, which reflected the polarization characteristic of ray radiation source, polarization-preserving fiber, optical system and so on. The measurement and the appraisal of the extinction ratio is mainly to accurate and calibrate operational parameter of polarized prism itself. The measurement accuracy of extinction ratio can not only influence the measurement precision of measuring and discriminating all kinds of polarization of optical radiation, but also influence detection and analyze polarization response of optical devices and instrument system that have the transition nature of polarized light by making use of polarizer. Therefore, accurate measurement of extinction ratio of polarized prism has very important meaning for the development of modern informationtechnology.This article altogether is divided into five chapters. The first chapter is the introduction partial. The second chapter and the third chapter introduces the polarized light rationale knowledge , generally used experimental technique and the principle of the polarization component extinction ratio measurement, and has made a simple elaboration to the measurement method characteristic to each kind of generally used extinction ratio measurement. In the fourth chapter, unifies the basic principle of "GXC-1 high extinction ratio measurement system", which was successfully developed by our institute and union advanced computer control technology, we carried on the consummation and optimized improvement to this measurement system. Because the light power stability and the photosource polarization stability of JD- III He-Ne laser, which used by the high extinction ratio measurement system, also the photosource instability influence to the measurement result is big. The predecessor once introduced servo method to compensate the instability of photosource. But because it used the hardware to compensate, compensated timeliness is not ideal. Therefore, we first the carried on the experimental test to JD- III He-Ne laser photosource stability, glanced through the work principle of He-Ne laser and many stability solutions. Also, has carried on the multianalysis to each kind of photosource stable control solutions and made the massive simulations computation and experiments. In the foundation of theoretical analysis and experiments, we designed a high performance attenuator, which could meets the need of the high extinction ratio measurement system, and carried on the experiment , which has proven its validity. In the actual measurement, we use the computer control stepper motor to change the light pass surfaces angle of two polarized prisms to cause the weaken multiple change. Thus, causes the detector work in the linear response scope. This weaken system not only realized the automation of the luminous intensity weaken, but also to be possible to obtain a relatively stable circularly polarized light. In order to further eliminate the influence of photosource instability to the measurement result, we aimed at the specific high extinction ratio measurement system, designed a new method, which compensates the light wave signal auto-adapted. Finally, in the foundation of photosource stability research, we made the improvement and optimization to the high extinction ratio measurement system. Used the computer and the SR830 phase-lock amplifier data communication realized the 16Bit A/D transformation of weak signal, thus, realized the automatic gathering of weak light information empirical datum under strong noise , and further carries on the data fitting analysis, finally calculates the extinction ratio of polarized prism sample. In the fifth chapter, we analyzed the datum processing method, the error source which the data possibly existed and the error reduce method of the designed system. The main work and the contribution of myself as the follows states: First, in the predecessor's foundation, carries on the experiment and the preliminary theoretical analysis to the light intensity and the polarization stability of JD- III He-Ne laser photosource which is used by the high extinction ratio measurement system. Second, in the high extinction ratio measurement system, for the first time, introduce the OE double output prism to separate the reference light signal and the survey light signal. Third, designed a high performance attentuator which to be possible to adjust the light intensity continuously, and has carried on the precise calibration to it. Fourth, for the first time, introduces auto-adapted compensate system to high extinction ratio measurement system and has obtained a good experimental effect. Fifth in the predecessor's foundation, unifies the advanced computer technology, basically realizes the test and the data processing intellectualization.After the investigation and study, we find that the measurement method which generally used only based on the most basic test method, therefore ,the test precision problem and so on is inevitable. In this article we used the successfully developed measurement system to carry on the extinction ratio measurement to some types of polarization prism and achieved the ideal effect.