光纤色散法测量闪烁体脉冲光谱

提出了一种利用光纤波长色散测量脉冲光谱的方法.由于具有较宽光谱的脉冲光在一定长度的光纤中传播时会发生波形展宽,需要根据测量和标定结果校正展宽的波形才能得到光源的实际光谱曲线.标定时首先利用ps级脉冲光源对测量系统进行时间响应标定,得到系统的时间响应函数；接着测量不同波长光的走时,得到不同波长的群折射率；最后测量光纤中的光谱衰减,得到各种波长的相对衰减或传输效率.利用以上3个标定结果,对波形进行数字逆卷积,并进行走时校正和衰减系数校正,即可对所得到的波形进行恢复.经实验测量和数据处理,得到了一种红光闪烁体的发光光谱曲线,其中心波长与用其他方法测到的中心波长的差小于2 nm,谱线形状基本一致.研究显示,在脉冲光的脉冲宽度远小于其色散展宽时,可以利用光纤的波长色散对脉冲光的光谱进行测量.

Measurement of pulse spectra for scintillator based on fiber dispersion

A new method to measure the spectrum of a pulse light was developed.As the pulse width could be broaden due to the dispersion when a pulse light passed through the optical fiber,the calibration and measurement were proposed to correct and recover the broaden waveform to obtain the real spectrum of a pulse light source.In calibration,the time response function of measuring system was gotten with a ps laser firstly;then the group refractive indexes at different wavelengths were obtained by measuring the time delay of given wavelengths;finally,the relative attenuation index of each wavelength in optical fiber was given by measuring the spectral attenuation.On the basis of the calibration results mentioned above,broaden waveform was recovered by the digital deconvolution,time delay and attenuation.The pulse spectrum of a red scintillator was measured with this method.Results demonstrate that the difference of the center wavelength of the scintillator given by this method and other methods is less than 2 nm,which shows the spectra of pulse light can be measured based on fiber dispersion when the pulse width is much less than its dispersion.