针对由理论计算得到的解调系数无法实现强度调制偏振光谱仪实验系统（以下简称“实验系统”）测量数据解调处理的问题，提出了测量参考光获取实验系统解调系数的解决方法。该方法通过测量已知偏振态参考光经过实验系统调制器后输出的强度谱，结合傅里叶变换、滤波和逆傅里叶变换等数字信号处理过程，可从测量结果中分离出实验系统的真实解调系数。分析了该方法的理论依据，给出了实验系统解调系数的实测结果，并利用得到的解调系数，对实验系统测量典型待测光源（近似自然光和完全线偏振光）的测量数据进行了解调处理。解调处理结果显示：在有效测量波段范围内(550～650 nm)，以卤钨灯为光源的平行光管直接输出光的偏振度值约为10%；经过线偏振器起偏后，其偏振度值接近100%，与实际分析结果完全相符。验证了强度调制系统解调系数参考光测量方法的可行性。

A novel method is presented to acquire the demodulation coefficients of the intensity-modulated spectropolarimeter (IMS) by measuring the reference light, for the demodulation coefficients obtained by theoretical calculation cannot demodulate the measured data. The demodulation coefficients of IMS can be separated from the intensity spectrum of the reference light passing through the modulator of the IMS, and it is necessary to process the intensity spectrum, such as IFFT, filtering and FFT etc. The principle of the method is analysed in details and the measured results of the demodulation coefficients for IMS prototype are presented. The measured data of quasi-natural light and polarized light from IMS prototype is demodulated by the demodulation coefficients obtained to verify their validity. Experimental results show that the polarization degree of the light from a tungsten-halogen lamp collimator directly is less than 10%, but it is about 100% when the light is polarized by a polarizer in the spectral range of 550~650 nm. These results are coincident with the theoretical results well, which verify the feasibility of the method presented before.