本文介绍的测定光强分布装置用光纤的一端接收被测定光束的某一小区域的光强,光纤的另一端密封在光电倍增管窗口前,把光电流输出信号接到函数记录仪的y轴,而X轴接入一随探针位置而变的信号,连继扫描就可以描绘出光强分布曲线.为了使用方便并加强抗干扰能力,扩大测量动态范围.设置了调制盘、选频放大器、相敏整流器、衰减器和对数放大器.这样就克服了光电倍增管光阴极光电转换不均匀的缺点. This article describes the measurement of light intensity distribution device with one end of the optical fiber receives the light intensity of a small area of ​​the measured beam, the other end of the optical fiber sealed in the photomultiplier tube window, the photocurrent output signal is connected to the function of the y-axis , While the X-axis access to a probe with the location of the signal change, with subsequent scanning can be plotted the light intensity distribution curve. In order to facilitate the use and enhance anti-interference ability, expand the measurement dynamic range set the modulation plate, frequency selective amplifier , Phase sensitive rectifier, attenuator and logarithmic amplifier, thus overcoming the shortcomings of non-uniform photoelectric conversion in photomultiplier tubes.