双Fabry-Perot干涉纳米测量控制系统的设计

设计了一种基于双Fabry-Perot干涉仪的新型纳米测量系统,阐述了系统各环节的数学模型。针对探针与样品表面相互作用的数学模型比较复杂的特点,详细设计了基于模糊控制理论的控制系统,提出了通过控制控针振动曲线不变进行纳米测量的理论依据及实测方法。在此基础上,对系统进行了仿真实验,实验结果充分证明了系统设计及理论依据的正确性。     

混凝土固化期收缩应变监测的光纤珐珀传感器

针对混凝土固化监测的难题,提出了采用光纤珐珀传感器进行混凝土固化过程中收缩应变监测的新方案,分析了光纤珐珀传感器的传感原理,研制出了相应的实验系统,对440mm×50mm×40mm的混凝土试件进行了实验,在试件两天的固化过程中监测到了130με的收缩应变.本文还对光纤珐珀应变传感器的温度稳定性能进行了理论分析及对比实验,实验结果表明,在一定条件下环境温度对光纤珐珀应变传感器的影响可忽略不计.     

双通道光纤通信波分复用滤光片的设计与模拟

讨论了在采用薄膜干涉方法分（合）波时,其中的关键器件－薄膜干涉滤光片的设计和镀膜监控误差模拟,主要介绍了一个波分复用双通道薄膜干涉滤光片的设计原理、设计过程、滤光片的性能及影响因素分析。并进行了假定监控误差下的镀膜过程的模拟。     

利用AOTF的可调谐光纤激光器的特性研究

提出了一种新型的可调谐光纤激光器 ,其谐振腔是由声光可调谐波长滤波器 (AOTF)和掺铒光纤构成的Fabry Perot腔。该激光器具有调谐方便 ,调谐速度快和调谐范围大的优点。在忽略激发态吸收和放大的自发辐射情况下 ,对该激光器的线宽和调谐特性以及阈值抽运功率和斜率效率进行了理论计算。在中心工作波长 15 5 0nm处 ,得到输出峰值的半极大值线宽 (FWHM)约为 0 2 6nm ,并且在 15 5 0nm附近 ,声波频率每改变 1MHz所调谐的峰值波长间隔约为 8 95nm。理论上 ,调谐范围只受掺铒光纤增益和滤波器带宽的限制。计算结果表明 ,该激光器的阈值抽运功率和斜率效率分别为 0 795mW和 15 15 %。     

Light trapping schemes in organic solar cells: A comparison between optical Tamm states and Fabry–Pérot cavity modes

Recently optical Tamm states at metal/photonic crystals interface have been applied in thin-film organic solar cells (OSCs) as a new light trapping scheme for photon absorption enhancement. In this work, we theoretically investigate this scheme thoroughly to optimize the absorption performance for such optical Tamm states based OSCs (OTS–OSCs). We find that the overall absorptivity of the OTS–OSCs can be improved by using photonic crystals bilayers with a higher refractive index contrast, which is a result of the more strongly enhanced field intensity in the active layers. The conventional Fabry–Pérot cavity modes based OSCs (FP–OSCs) are also studied for comparison, whose absorption performance is found to be strongly dependent on the refractive index of the additional dielectric layer. These two schemes based OSCs exhibit comparable absorption performance in aspects of absorption enhancement, field distributions, and angle effect in the planar case. However, the proposed OTS–OSCs exhibit ～10% higher overall absorptivity than that for the FP–OSCs in the corrugated case, if both OSCs exhibit the same overall absorptivity in the planar case. The reduced absorption in the corrugated FP–OSCs is a result of the strong scatterings induced losses in the metal, which can be avoided by the photonic crystals bilayers in the OTS–OSCs. Therefore, the proposed Tamm states based scheme shows a higher value in corrugated OSCs.     

高精度双波长光纤F-P传感系统正交特性研究

针对光纤Fabry-Perot(F-P)传感器在实际应用中,受外界环境干扰,造成输出精度较低,提出了一种采用波分复用器(DWDM)输出两路正交信号的双波长稳定系统。基于微分进化(DE)算法建立了光纤F-P传感系统的双波长稳定优化模型,设计了一高正交精度传感系统,构建了传感系统正交实验方案,研究了其正交输出特性和正交误差。结果表明,DE算法运行速度快,能在较短运行时间内得到全局最优解,可很好的用于光纤F-P传感系统结构优化,误差小于10-3;设计的传感系统具有较高的正交输出精度,当腔长变化为-1¹μm时,两路工作波长相位差接近π/2,传感系统正交误差均小于6%,具有良好的稳定性和抗干扰能力,能满足实际需求。     

Dual-wavelength erbium-doped fiber laser with asymmetric fiber Bragg grating Fabry-Perot cavity

A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating（FBG） Fabry-Perot（FP） cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility.     

Impact of signal filling factor for switching in reflective vertical cavity-based fast semiconductor saturable absorbers

A numerical model on reflective vertical cavity-based fast semiconductor (carrier recombination time in ps regime) saturable absorbers (VC-FSSA) is investigated for all-optical high-speed future applications, where the fluctuation of cavity optical length due to thermo-optic effects and cavity heating, and optically induced carrier density change are considered simultaneously with the increase of input signal intensity. The phase-shift due to thermal-optic effects and cavity heating is very important for high-speed device performances. At first, intensity and wavelength bi-stabilities are modelled with the different intensity time filling factor of RZ modulated pump signals and also, with the different input intensities, where the intensity tuning time is considered at few μs. Then the inverse saturation characteristics of reflectivity for the universal logic operations are shown for probe signal with the proper wavelength, which can control the negative effects of optically induced heating effects. These characteristics can be used for the high-speed thermally stable bi-stable optical switch and all-optical logic applications.     

Detonation in TATB Hemispheres

Streak camera breakout and Fabry‐Perot interferometer data have been taken on the outer surface of 1.80 g/cm³ TATB hemispherical boosters initiated by slapper detonators at three temperatures. The slapper causes breakout to occur at 54° at ambient temperatures and 42° at −54 °C, where the axis of rotation is 0°. The Fabry velocities may be associated with pressures, and these decrease for large timing delays in breakout seen at the colder temperatures. At room temperature, the Fabry pressures appear constant at all angles. Both fresh and decade‐old explosive are tested and no difference is seen. The problem has been modeled with reactive flow. Adjustment of the JWL for temperature makes little difference, but cooling to −54 °C decreases the rate constant by 1/6th. The problem was run both at constant density and with density differences using two different codes. The ambient code results show that a density difference is probably present, but it cannot be quantified.