The effects of gamma ray (γ-ray) radiation and electron beam (e-beam) radiation on Rayleigh scattering coefficient in single-mode fiber are experimentally investigated. Utilizing an optical time domain reflectometry (OTDR), the power distribution curves of the irradiated fibers are obtained to retrieve the corresponding radiation-induced attenuation (RIA). Based on the backscattering power levels and the measured RIAs, the Rayleigh scattering coefficients can be characterized quantitatively for each fiber sample. Under the given radiation conditions, Rayleigh scattering coefficients have been changed very little while RIAs have been changed significantly. Furthermore, simulations have been implemented to verify the validity of the measured Rayleigh scattering coefficient, including the splicing points.

采用稀土掺杂光纤（又称有源光纤）制成的光纤激光器和光纤放大器具有优异的光学性能，已被广泛应用于太空、核电设施及高能物理设施中。有源光纤对辐照十分敏感，当其处于上述辐照环境时易产生辐致损耗，导致光学性能迅速恶化，因此，提高有源光纤的抗辐照性能十分有必要。本文简要介绍了有源光纤在辐照环境下的应用背景以及面临的问题，并从有源光纤的辐照特性、影响辐照特性的因素和有源光纤抗辐照手段三个方面详细介绍了国内外抗辐照有源光纤的研究进展，最后对抗辐照有源光纤未来的研究趋势进行了展望。

A new radiation-hard germano-silicate glass optical fiber with a pure silica glass buffer and a boron-doped silica glass inner cladding was fabricated for temperature sensor application based on the fiber Bragg grating (FBG) under --ray irradiation environment. The temperature dependences of optical attenuation at 1550.5 nm and Bragg reflection wavelength shift from 18 ℃ to 40 ℃ before the γ-ray irradiation were about 4.57×10^–4 dB/ ℃ and 5.48 pm/ ℃ , respectively. The radiation-induced optical attenuation at 1550.5 nm and the radiation-induced Bragg reflection wavelength shift under the γ-ray irradiation with the total dose of 22.85 kGy at 35 ℃ were about 0.03 dB/m and 0.12 nm, respectively, with the γ-ray irradiation sensitivity of 5.25×10^–3 pm/Gy. The temperature and the γ-ray irradiation dependence of optical attenuation at 1550.5 nm in the FBG written fiber with boron-doped silica glass inner cladding were about 6 times and 4 times lower than that in the FBG written fiber without boron-doped silica glass inner cladding under a temperature change from 18 ℃ to 40 ℃ and the γ-ray irradiation with the total dose of 22.85 kGy at 35 ℃, respectively. Furthermore, the effect of temperature increase on the Bragg reflection wavelength of the FBG written fiber with boron-doped silica inner cladding was much larger about 1000 times than that of the γ-ray irradiation. However, no influence on the reflection power of the Bragg wavelengths and the full width at half maximum (FWHM) bandwidth under temperature and the γ-ray irradiation change was found. Also, after the γ-ray irradiation with the dose of 22.85 kGy, no significant change in the refractive index was found but the residual stresses developed in the fiber were slightly relaxed or retained.

为了提高辐射传感技术的探测精度、探测剂量范围以及监测点数量, 研究了使用光时域反射仪(OTDR)技术观测单模光纤的辐射致衰减(RIA)效应, 从而实现分布式辐射传感应用的可行性。通过计算OTDR曲线中光功率衰减斜率, 建立了单模光纤RIA与辐射剂量的线性关系。采用具有合适RIA效应的单模光纤, 有望实现具有高空间分辨率的长距离分布式辐射剂量监测。

稀土掺杂有源光纤激光器或放大器具有重量轻、体积小、电光转换效率高等优点,在空间激光通讯、空间激光雷达、太空垃圾处理及**等方面有重要应用价值。然而,常规稀土掺杂有源光纤在太空辐射环境中的辐射诱导损耗是非稀土掺杂无源光纤的1000倍以上,这给面向空间应用的光纤激光器或放大器的长期稳定性带来了严峻挑战。本文简要介绍了太空辐照环境、石英光纤在太空中的应用需求和所面临的挑战;然后从三个方面详细介绍了当前国内外在耐辐照有源光纤领域取得的最新研究成果:1)有源光纤辐致暗化机理,2)有源光纤耐辐射特性的影响因素,3)提高有源光纤耐辐射特性的方法;最后,对耐辐照有源光纤的未来研究方向进行了展望。

研究了辐射剂量对光纤辐射致衰减及其对辐射致衰减温度依赖性的影响.对锗磷光纤进行不同辐射剂量的辐照，搭建了光纤辐射致衰减实验装置用以分析辐射剂量对光纤辐射致衰减的影响.用辐照并充分退火后的光纤搭建光纤辐射致衰减温度依赖性实验装置进行测试，对锗磷掺杂光纤的辐射致衰减与辐射剂量间进行了模型分析.分析发现:锗磷掺杂光纤在1 310 nm的辐射致衰减主要取决于P1心,但吸收峰位于紫外可见波段的POHC色心等也会对光纤在1 310 nm波段的光纤辐射致衰减产生影响，尤其是在高辐照剂量的情况下.实验结果表明，随着辐照剂量的增加，光纤的辐射致衰减显著增加.经过不同辐射剂量辐照并充分退火的锗磷光纤，在－40℃~60℃温度范围内光纤辐射致衰减具有单调稳定的温度依赖性.且光纤辐射致衰减的温度灵敏度随着辐照剂量的增加而增加.该研究不仅可以使光纤在复杂辐射环境中更好地使用，而且还可以利用光纤辐射致衰减稳定的温度依赖性研制温度传感器.

在空间辐射环境下，光纤会产生辐射致衰减(RIA)，严重影响光纤在辐射环境中的应用。为了保证光纤在辐射环境中的工作性能，需要对光纤辐射致衰减效应进行研究。从辐射与光纤相互作用的机理出发，说明了辐射条件下引起光纤主要衰减的色心的形成和退化，并详细分析了辐射条件、光纤参数和传导光波等因素对光纤辐射致衰减的影响。在此基础上，总结了光纤辐射致衰减的主要模型，包括幂律模型、多成分饱和指数模型和拓展多成分饱和指数模型等。最后，介绍了光纤辐射致衰减效应的应用。