基于FPGA和DS18B20的温度光栅的波长标定方法

Wavelength calibration method of temperature FBG based on FPGA and DS18B20

提出了一套基于FPGA(fiber-Bragg-grating)和DS18B20的温度布拉格光栅的波长标定方法。基于DS18B20对外界温变的实时响应特性,将数字温度传感器DS18B20与连接了光谱仪的温度光纤布拉格光栅FBG置于同一温度场中,以现场可编程门阵列FPGA(field-programablegate-array)作为数据处理和控制芯片,设计了通过串口发送智能指令对温场变化的实时监控和显示系统。方法中不需要温箱进行恒温控制,降低了FBG波长标定的成本及功耗。实验表明,标定出的波长-温度曲线线性度为0.999,测得光栅的温度灵敏度系数为9.899pm/℃,与用恒温箱测得的结果10.468pm/℃相差0.569pm/℃,在系统允许误差0.619pm/℃范围内,验证了该方法的准确性。

Based on real-time response of DS18B20 to external temperature, digital temperature sensor DS18B20 is placed in the same temperature field as the temperature fiber Bragg grating （FBG） connected with the spectrometer. Taking field-programable-gate-array（FPGA） as a data processing and control chip, real-time monitoring and display system on the temperature field change is designed through serial port to send intelligent instructions. This method does not need thermostat to control temperature, which reduces the cost and power consumption of FBG wavelength calibration. Experimental results show that the linearity of wavelength-temperature curve is 0. 999 , and the temperature sensitivity coefficient of FBG is 9. 899 pm/℃, which differs from the result 10. 468 pm/℃ measured with thermostat to 0. 569 pm/℃ . The error falls in the range of 0. 619 pm/℃ allowed by the system, which verifies the accuracy of the method.