叙述了在266 nm波长点测量紫外探测器和紫外光功率计非线性的原理。提出了利用功率叠加法测量紫外探测器非线性参数的新思路, 设计并成功研制了精确测量紫外探测器非线性的装置。利用偏振分光棱镜实现光路的分离与合并, 提高了功率非线性测量的动态范围。采用外界杂散光屏蔽技术, 减小了背景光和杂散信号对测量结果的影响。编写了自动测量软件, 优化了数学模型, 降低了测量不确定度。实验结果表明, 在1 nW～100 μW的功率范围内, 测量重复性小于0.3％, 非线性扩展测量不确定度优于0.8％(k=2)。

The principle of measuring nonlinearity of ultraviolet photodetector and power meter at 266 nm was presented in this paper. A new technique is proposed for measuring the nonlinearity of ultraviolet photodetector using the power superposition method. The facility of accurate measuring ultraviolet photodetector nonlinearity has been developed. The power nonlinearity dynamic range is widened by using a polarizing beam splitter cubes for beam splitting and combining. The effect of background and scattering signals on the measurement results is reduced by the light shield. The measurement uncertainties are reduced by automatic test programme and optimized model. Results show that in the power range of 1 nW～100 μW, the repeatability of the results is better than 0.3％ and the typical expanded measurement uncertainty of nonlinearity is less than 0.8% (k=2).