变迹-啁啾光栅在瞬态温度测试中的研究与应用

为了快速准确地获取火炮发射时炮管的瞬态温度场信息，设计了基于变迹-啁啾光纤光栅传感器的瞬态测温系统。系统采用啁啾光纤光栅实现对回波光的带宽调制，从而使回波光带宽大幅提高，大大增加了系统带光栅传感器数量及回波光能量。在分析了五种常见变迹函数切趾性能的基础上，系统采用超高斯函数形式完成对回波信号的切趾处理，有效地抑制了由于啁啾调制所造成的旁瓣增大以及光谱抖动，使系统符合瞬态温度测试的设计要求。实验采用调制范围1 532.0～1 548.0 nm的变迹-啁啾光栅传感器，并在炮管上均匀缠绕，共50个测试点位。针对某型火炮发射时炮管的瞬态温度进行测试，实验数据与WRP-130S型高速温度探测器的测试结果比较。实验结果显示，该系统与WRP-130S型探测器测温结果相近，平均误差小于2%，在温降平稳区优于1%。测试结果中，温度-波长数据满足1 ℃约引起0.041 3 nm(均值)的波长偏移。该系统在一次采集过程中可获得50个独立位置的瞬态温度，大大提高了炮管温度场重建的效率。

The Research and Application of Transient Temperature Test Based on Apodized-Chirped FBG

In order to quickly and accurately obtain the transient temperature field information of the barrel when the gun is fir-ing,the transient temperature measurement system was designed with apodized-chirped fiber Bragg grating (FBG)probe.In the system,chirped fiber grating was used to modulate the bandwidth of echo light.The bandwidth of echo light had been greatly improved.So the number of apodized-chirped FBGs in one fiber could be greatly increased,and the energy of echo light was in-creased too.The performances of five common apodization functions were analyzed,and the super-Gaussian function was used to process the echo signals in the system.This function effectively suppressed sidelobe increases and spectral dispersion caused by chirp modulation,which indicated that it could meet the design requirements of the transient temperature measurement.50 apo-dized-chirped FBGs,which evenly wound on the barrel,were used in the experiments,and they modulation range was from 1 532.0 to 1 548.0 nm.Transient temperature of a certain type of gun barrel was tested when it fired,and test data from the system were compared to WRP-130S high-speed temperature detector.Experimental results show that the two methods are simi-lar ones with average error of less than 2%,and better than 1% in the region of temperature steady drop.1 ℃ can cause 0.041 3 nm wavelength shift in temperature-wavelength data.Transient temperatures of 50 independent positions can be obtained in an acquisition,so the efficiency of the barrel temperature field reconstruction is greatly improving.