Zhao Qiang, Wang Yinglong, Sun Peng, Du Dawei, Yu Luyao, Zhang Jianwei, Ding Baoyan, Han Guihai, Qu Yi
Appl Opt. 2022 Mar 10;61(8):2089-2095. doi: 10.1364/AO.450325.
Traditional electrical expendable bathythermograph (XBT) is designed to fall at a known rate based on a great deal of experiments so that the depth of the temperature profile can be inferred from the time it enters the water. Unlike the traditional electrical XBT, which derives the depth from fall-rate equations, we propose an all-optical fiber (AOF) XBT (AOF-XBT) based on cascade of two fiber Bragg gratings (FBGs). In the AOF-XBT, the depth data comes from one FBG, which responds in real time to the pressure acting on the diaphragm, and temperature data can be measured via the other FBG simultaneously. First, the pressure and temperature response characteristics of the AOF-XBT are analyzed based on a finite element method. Then, the temperature and pressure calibrations for the AOF-XBT is completed after they are packaged. Results show that the mean-temperature sensitivity of two sensors are 14.765 and 13.705 pm/°C in the range of 5°C-30°C, and the mean-pressure sensitivities are -2.75586 and -3.00472/ in the range of 0-0.6 MPa, respectively. At last, by comparing the results obtained from the AOF-XBT and the SBE 911plus CTD that tested in the sea area of Weihai, the trends of the temperature-depth profile from the two devices are consistent, which presents a new all-optical technique to provide full ocean temperature-depth profile observations.
传统的电子式抛弃式温深仪（XBT）是基于大量实验设计成以已知速率下落，以便能根据其入水时间推断出温度剖面的深度。与通过下落速率方程推导深度的传统电子式XBT不同，我们提出了一种基于两个光纤布拉格光栅（FBG）级联的全光纤（AOF）XBT（AOF-XBT）。在AOF-XBT中，深度数据来自一个实时响应作用在隔膜上压力的FBG，同时温度数据可通过另一个FBG进行测量。首先，基于有限元方法分析了AOF-XBT的压力和温度响应特性。然后，在AOF-XBT封装完成后进行温度和压力校准。结果表明，两个传感器在5°C至30°C范围内的平均温度灵敏度分别为14.765和13.705 pm/°C，在0至0.6 MPa范围内的平均压力灵敏度分别为-2.75586和-3.00472/。最后，通过比较AOF-XBT与在威海海域测试的SBE 911plus CTD所获得的结果，两种设备的温度-深度剖面趋势一致，这提出了一种新的全光技术来提供全海洋温度-深度剖面观测。
