光纤陀螺随机游走系数的分析研究

分析了产生随机游走误差的机理,分别采用有关标准和Allan方差进行了随机游走系数的分析和计算。结果表明:随机游走系数是衡量光纤陀螺噪声水平的重要指标,其值的大小体现了陀螺的极限精度。采用Allan方法表述光纤陀螺的静态指标,物理概念清晰,方法简便。     

Effect of radiation-induced mean wavelength shift in optical fibers on the scale factor of interferometric fiber optic gyroscope at a wavelength of 1300 nm

In order to analyze the effect of wavelength-dependent radiation-induced attenuation (RIA) on the mean transmission wavelength in optical fiber and the scale factor of interferometric fiber optic gyroscopes (IFOGs), three types of polarization-maintaining (PM) fibers is tested by using a ⁶⁰Co γ -radiation source. The observed different mean wavelength shift (MWS) behaviors for different fibers are interpreted by color-center theory involving dose rate-dependent absorption bands in ultraviolet and visible range and total dose-dependent near infrared absorption bands. To evaluate the mean wavelength variation in fiber coil and the induced scale factor change for space-borne IFOG under low radiation dose in space environment, the influence of dose rate on the mean wavelength is investigated by testing four germanium (Ge) doped fibers and two germanium-phosphorus (Ge-P) codoped fibers irradiated at different dose rates. Experimental results indicate that the Ge-doped fibers show the least mean wavelength shift during irradiation and their mean wavelength of optical signal transmitting in fibers will shift to shorter wavelength in low-dose-rate radiation environment. Finally, the change in the scale factor of IFOG resulting from the mean wavelength shift is estimated and tested, and it is found that the significant radiation-induced scale factor variation must be considered during the design of space-borne IFOG.     

Temperature dependence of radiation-induced attenuation of optical fibers

We investigate the temperature dependence of radiation-induced attenuation (RIA) at 1 310 nm for a Ge/P co-doped fiber after a steady-state γ-ray irradiation.A γ irradiation facility 60Co source is used to irradiate the fiber at a dose rate of 0.5 Gy/min,satisfying a total dose of 100 Gy.The test temperature ranges from-40 to 60℃ by 20℃,and the RIA of the fiber is obtained using a power measuring device.The experimental result demonstrates that RIA exhibits a steady,monotonic,and remarkable temperature dependence after approximately 48h of accelerated annealing at 70℃.The optical fiber irradiated with a high dose and annealed sufficiently can be used as a temperature sensor.     

A radiation-temperature coupling model of the optical fiber attenuation spectrum in the Ge/P co-doped fiber

A radiation-temperature coupling model of optical fiber attenuation spectrum has been developed. The spectrum in Ge/P co-doped fiber ranging from 800 nm-1600 nm at different temperatures and doses was measured and decomposed according to the configurational coordinate model based on which the power-law model was employed to predict the intensity of the color center absorption band at different doses. And the fiber loss in space was predicted by the model. This work will benefit the application of fibers in a complicated radiation environment.     

Method for measurement of fusion-splicing-induced reflection in a photonic bandgap fiber-optical gyro

We propose a method for the real-time measurement of the reflection at both splicing points between a photonic bandgap fiber coil and conventional fiber during the process of fusion splicing in a photonic bandgap fiber optical gyroscope(PBFOG), using the interference among the secondary waves, which arise from the fusion splicing points and the mirror face produced by intentionally cutting the bear end of the coupler. The method is theoretically proven and experimentally verified in a practical PBFOG, and it is significant for inline examination of the fusion splicing quality and evaluation of the PBFOG performance.     

Phenomena of optic-bound effect on fibre optic gyro

The optic-bound effect on fibre optic gyro (FOG) precision is analysed theoretically, and formulas describing the change of FOG light power under the action of optic-bound effect are given. It is confirmed that optic-bound effect is a main instantaneous non-reciprocity effect of FOG in addition to the Sagnac effect and can lead to a dynamic error of FOG in practical environments. An approach to suppressing or eliminating the error due to the optic-bound effect is presented and verified experimentally. The result shows that the approach is valid and the precision of FOG is improved observably.     

油溶性CuInS2/ZnS量子点的制备及其温敏性聚丙烯酰胺胶束介导的水相转移

采用非热注法成功制备了高质量的油溶性CuInS₂/ZnS核壳量子点, 量子点的荧光发射峰在可见光到近红外范围内可调(550~800 nm), 且荧光量子产率最高达80%。本文进一步利用具有温敏特性的聚丙烯酰胺胶束作相转移剂, 成功地将油溶性的CuInS₂/ZnS核壳量子点转移入水相。水相中自组装形成的CuInS₂/ZnS量子点-胶束复合物不仅具有良好的荧光性质, 而且胶束原有的灵敏的热响应性被保留。这些研究初步表明, 无镉的低毒的CuInS₂/ZnS量子点可作为纳米胶束的荧光示踪探针。     

基于FPGA内部自激振荡与温度相关性的温度传感器

温度是IMU及其他导航器件等精密仪器中需要监测的重要参数,传统的温度监测一般使用热电偶或者数字温度传感器(如DS18B20)等,监测程序复杂,功耗高,因此使用精密仪器中广泛采用的FPGA芯片独立完成高集成度、低功耗温度监测具有重要意义。在FPGA中通过搭建环形振荡器产生了自激振荡信号,该信号周期与FPGA芯片温度具有正相关性,通过对振荡信号周期的检测完成了对温度的监测,设计了一种以FPGA芯片同时作为敏感头和处理模块的温度传感器。通过对Xilinx Virtex-2系列FPGA芯片进行实验,得到该传感器在-40℃⁺60℃的范围内具有优于0.1℃的分辨率,优于0.5℃的检测精度,满足一般温度监测需要。实验表明该传感器具有功耗低、集成度高、可靠性好等优点。     

Effect of radiation-induced mean wavelength shift in optical fibers on the scale factor of an interferometric fiber optic gyroscope at a wavelength of 1300 nm

In order to analyze the effect of wavelength-dependent radiation-induced attenuation (RIA) on the mean trans- mission wavelength in optical fiber and the scale factor of interferometric fiber optic gyroscopes (IFOGs), three types of polarization-maintaining (PM) fibers are tested by using a 60 Co γ-radiation source. The observed different mean wave- length shift (MWS) behaviors for different fibers are interpreted by color-center theory involving dose rate-dependent absorption bands in ultraviolet and visible ranges and total dose-dependent near-infrared absorption bands. To evaluate the mean wavelength variation in a fiber coil and the induced scale factor change for space-borne IFOGs under low radiation doses in a space environment, the influence of dose rate on the mean wavelength is investigated by testing four germanium (Ge) doped fibers and two germanium-phosphorus (Ge-P) codoped fibers irradiated at different dose rates. Experimental results indicate that the Ge-doped fibers show the least mean wavelength shift during irradiation and their mean wavelength of optical signal transmission in fibers will shift to a shorter wavelength in a low-dose-rate radiation environment. Finally, the change in the scale factor of IFOG resulting from the mean wavelength shift is estimated and tested, and it is found that the significant radiation-induced scale factor variation must be considered during the design of space-borne IFOGs.