高消光比测试系统衰减器的研究

为了提高消光比测试系统的测试精确度,利用偏振干涉原理研究设计了一种用于此系统的衰减器,并对它的工作机理进行了详细分析。此衰减器主要包括3个偏光棱镜,1个λ/4波片(632.8nm),两个步近电机。它可以对光强度进行连续调节,其调节范围在0~60dB之间,插入损耗小于1.5dB,消除了以往更换固定衰减量的衰减器带来的误差。此光衰减器用在高消光比测试系统中可以得到优于10-7量级的消光比,它不仅可以用于高消光比测试系统,同样可用于其它光学测试系统。当用消色差波片代替λ/4波片时,它能对多种波长的光进行衰减,扩大测试系统对光谱区的使用范围。

Study of the attenuator for the high extinction ratio testing system

In order to improve the measuring accuracy of the intelligence high extinction ratio measuring system,the polarization interference principle is used to study and design an attenuator used in the system,and the attenuator's principle is analyzed carefully. The attenuator is consisted of three polarization prisms,one λ/4 wave-plate(λ=632.8nm),and two stepper motors. It can continuously adjust intensity of light within the range of about 0～60dB and the insertion lossof less than 1.5dB,so the aberration generated by changing attenuator with fixing attenuation value can be canceled effectively. If the attenuator is used to measure the extinction. the extinction ratio better than 10 －7 can be obtained. The attenuator can be used not only in the high extinction ratio measuring system,but also in other optical measuring systems. The attenuator can adjust kinds of wavelength lights with achromatic plate in place of λ/4 wave-plate,so the useful range can be expanded.