基于薄膜滤光片的角度调谐系统设计

基于薄膜滤光片角度调谐的基本原理,实现了一种具有较宽波长调谐范围的可调窄带滤光器。通过优化机构装置参量,利用步进电机精确控制滤光片的入射角度。通过对多腔窄带薄膜滤光片的膜系结构及其等效折射率的计算,得到了滤光片透射中心波长与入射角度的关系式。制备了一个包括步进电机及转动机构在内的滤波器角度调谐装置,在1543-1563...     

电调谐液晶滤光片及其在光纤通信中的应用

波长可调谐滤光器在波分复用、全光交换系统等领域具有广泛的应用价值。本文就电调谐液晶滤光片的滤光原理进行了分析,并介绍了其在光纤通信领域中的应用     

角度调谐滤光片补偿装置设计及实验研究

倾斜入射时滤光片的透射光会出现光路偏移以及光斑模场的形变,所以在测试制备的100 GHz低偏振相关损耗的角度调谐滤光片时其透射光谱的插入损耗和波形的高斯化现象会随着入射角度的加大而迅速增加.根据薄膜矩阵理论建立模型模拟了透射模场的偏移变化,并设计和制备了一种动态补偿装置,在实验中证明该设计能在保持光准直器位置固定的情况下有效地减少透射波形的损耗和高斯化现象,使得角度调谐滤光片能达到理论设计中20 nm的可调谐范围.     

瑞利多普勒激光雷达超窄带滤光器的设计

目前中国科学技术大学车载激光雷达已经实现了对于15~60 km中性大气风场的夜间连续观测,鉴于白天观测的信噪比受到背景光的限制,因此,设计了一种利用现有干涉滤光片结合固态FP标准具的超窄带滤光器,用于实现背景噪声的降低。提出了一种结合鉴频器参数确定FP最佳参数的方法,得出了FP标准具的参数,实现了带宽为8.4 pm、中心波长为354.73 nm、自由光谱间距为150 pm、峰值透过率高于0.67的滤光器,将背景噪声降低到原来的十八分之一。该滤光器有效提高了系统信噪比,减小了风速误差,同时计算了温度、角度变化对滤光器带宽、中心波长和透过率的影响,设计了一种角度调谐的方法。实验结果与理论值具有较高的一致性。     

电光可调滤光器

本文描述了一种可调滤光器,这种可调滤光器,在双折射电光晶体的寻常偏振光与异常偏振光之间于相位匹配波长下利用空间周期直流电场耦合光能.本文描述的一个具体装置是一片LiTaO_3置于近交的偏振片间用横向电场工作,引用(?)olc的双折射滤光器及Harris声光滤光器进行摸拟,这种电光滤光器是经由分离的可寻址的指状电极列阵来改变电场的空间周期而进行调谐.美国已演示的可调谐性从4,700埃至4.5微米透射实验的结果与外加电压的关系和带宽与通过波长的关系和理论很一致.着重指出了这类电子滤光器的灵活性有可能通过非周期电压分布来合成任意传递函数.     

连续激光作用下滤光片熔坑形成机理研究

在532nm波长连续激光辐照ZnS/SiO2/K9 630～690nm多层膜滤光片的损伤实验的电镜扫描分析下观察到了"熔坑"的现象,根据这个现象建立了含有Pt杂质的532nm波长连续激光辐照ZnS/SiO2/K9 630～690nm多层膜滤光片的热损伤模型.结合温度场的计算,研究了532nm连续激光辐照630～690nm多层薄膜滤光片时杂质周围产生的温升效应,通过对计算结果与实验结果的比较,分析了杂质对滤光片薄膜激光损伤的影响.分析了连续激光作用下杂质对滤光片的破坏机制,解释了滤光片熔坑产生的原因.     

基于全介质薄膜法布里珀罗滤光片的1550 nm可调谐外腔半导体激光器

提出并实现了一台基于单腔全介质薄膜法布里珀罗滤光片的1550 nm可调谐外腔半导体激光器。介绍了其内部的光学元件及其工作原理,随后对该半导体激光器的纵模输出特性进行了理论分析,搭建了该可调谐外腔半导体激光器。在不同的实验条件下,对该可调谐外腔半导体激光器在调谐过程中的输出波长、线宽及功率进行了实时同步测量。由所测数据总结出最佳实验条件,并得到了此条件下可调谐外腔半导体激光器的各相关参数。该可调谐外腔半导体激光器有一个线性的无跳模波长调谐区域(1547.203~1552.426)nm,一个稳定的输出光功率范围(40~50)μW,以及一个稳定的输出单纵模分布、线宽范围(100~150)MHz。该可调谐外腔半导体激光器可用于环境监测、原子与分子激光频谱研究、精确测量等领域。     

一种基于TFF的50GHz平顶型可调谐光滤波器

文章介绍了一种基于薄膜滤光片(TFF)技术的50 GHz通道间隔、平顶型可调谐光滤波器(TOF)的研制.对角度调谐干涉滤光片的原理进行了讨论,同时对超窄带膜系设计进行了优化.研制出的器件样品经过全面测试,实现了40 nm波长范围内96个ITU-T通道的可选择下路,为智能化的光网络提供了一种低成本、高性能的动态波长选择方案.     

宽调谐室温Co:MgF2激光器

用双折射滤光片不同干涉级次和多组谐振腔镜连续调谐室温Co:MgF2激光器,波长调谐范围达到1700～2550nm,在2090 nm峰值波长的输出能量及效率分别为115 mJ和16%.     

可见光波段的窄带导模共振滤光片的设计

为了使导模共振滤光片能在可见光范围内表现出良好的滤光效果,根据严格耦合波理论和等效介质理论,提出基于半导体材料单晶氧化锌薄膜的亚波长导模共振光栅滤光片的结构设计。通过仿真分析可知,该滤光片在可见光范围内的475nm,530nm与650nm波长处,反射效率都达到了100%,旁带反射率低于4%,并且峰值带宽均小于0.3nm。结果表明,该滤光片能分别在可见光的红、绿、蓝波段表现出良好的滤光效果,可以作为三基色的滤光片,在彩色合成与调制中得到重要的应用。     

Tunable thin-film filter with low angle sensitivity

Conventional angle-tuned thin-film filters have serious angle sensitivity for their low spacer effective refractive index, and it is difficult to fabricate their angle control system. In this paper, we propose and fabricate a novel 100 GHz angle-tuned thin-film filter stack with low angle sensitivity, which uses the high refractive index material TiO2 as the spacer, and its incident angle can be expanded to 25°. Compared with the traditional Ta2O5-SiO2 thin-film filter stack, the novel stack has fewer layers. Using the polarization beam splitters and the half wave plates, the polarization sensitivity of the angle-tuned filter can also be suppressed. Simulation results and the experiments show that the thin-film filter with low angle sensitivity has an effective tuning range of 33 nm, which can cover the whole C-band, and its angle control system is easy to be fabricated.     

An adaptive wavelength tunable optical filter employing anangle-tuned interference filter and an intelligent digital controller

This paper describes an adaptive wavelength tunable optical filter, which is composed of an angle-tuned interference optical filter and an intelligent digital controller. The new angle-tuned interference filter consists of a dielectric interference optical filter and a piezoelectric angle-tuning mechanism. It achieves quick wavelength switching within 2.5 ms in a 30 nm tuning range and a sufficiently low crosstalk less than -30 dB. The intelligent digital controller has two functions: wavelength tracking and wavelength channel selection. Combining these technologies, we have developed a practical low-cost tunable filter suitable for a post-optical-amplifier filter in a high-sensitivity detection system and a channel selector in a WDM system that requires 10-100 ms channel selection time. With a wavelength tracking operation, we have confirmed -35 dBm high-sensitivity detection in 20 nm wavelength range in a 10 Gb/s system. We have also confirmed a wavelength channel selection operation within 18 ms in a three-channel wavelength division multiplexed (WDM) system whose channel spacing is 4.4 nm     

Bragg grating fast tunable filter for wavelength divisionmultiplexing

A Bragg grating fast tunable filter prototype working over a linear tuning range of 45 nm with a maximum tuning speed of 21 nm/ms has been realized. The tunable filter system is based on two piezoelectric stack actuators moving a mechanical device thus compressing an apodized fiber Bragg grating. The filter allows both traction and compression and can work in transmission and in reflection. It is designed to work with a channel spacing of 100 GHz according to the ITU specifications for wavelength division multiplexing systems     

单片机控制步进电机实现光纤光栅外腔半导体激光器调谐

本文介绍了步进电机在光纤光栅外腔半导体激光器调谐中的应用,利用步进电机角位移与控制脉肿之间的精确同步,控制脉冲宽度与频率,经连杆、齿轮等精密机械传动后,带动千分尺转动,控制光纤光光栅拉伸,从而实现利用单片机控制步进电机对外腔半导体激光光栅波长进行调谐。     

Tuning of an erbium-doped fiber ring laser based on heating a tapered fiber filter

An erbium-doped fiber ring laser (EDFRL) with wavelength tuning is reported. The laser has a Mach–Zehnder fiber interferometer (MZFI) based on tapers as an intracavity filter, which spectral interference transmission spectrum is modified by external refractive index changes induced by temperature variations in the 25–110 °C range. The MZFI is immersed in a glycerol solution, which refractive index is modified by controlled temperature changes, which allows the tuning of the laser wavelength determined by the interference fringes. Wavelength tuning of 12 nm was measured. This approach is very simple, portable and inexpensive over traditional methods to tune a fiber laser. In addition, the tuning mechanism do not require a solution replacement to operate.     

Design and fabrication of GaAs-GaAlAs micromachined tunable filter with thermal strain control

In this paper, we present the design and fabrication of a novel GaAlAs-GaAs micromachined vertical cavity filter with a thermal strain control layer for wide wavelength tuning. The integration of a thermal strain control layer and heating element enables wavelength tuning induced by heating. The proposed tunable filter under thermal tuning operation provides us large tuning range over conventional micromachined tunable filters using electrostatic force. The calculated result shows a possibility of large continuous tuning range of over 100 nm. We fabricated a micromachined GaAlAs-GaAs vertical cavity filter with a strain control layer. The temperature dependence of the filter can be freely controlled either with temperature insensitive operation or with an enhanced temperature dependence, which depends on the thickness of the thermal strain control layer. We demonstrate a thermal wavelength tuning of 53 nm with a low tuning voltage of 6.1 V for the first time.     

参考谱线法测量倍频Nd:YAG激光器调谐波长的研究

为了精确测量倍频Nd:YAG激光器的调谐波长,采用碘分子在532nm附近的强吸收谱线作为频率稳定的绝对参考谱线,建立了以碘蒸气为标定物的激光调谐波长测定系统,实际测量了碘蒸气吸收谱线.通过谱线的特征结构与理论吸收谱线的比较,得到了倍频Nd:YAG激光器调谐频率与外加偏压及电位计旋转角度的对应关系,并确定了激光频率跳变点的位置,最后给出了倍频Nd:YAG激光器的调谐范围.结果表明,碘吸收谱线法可以用来精确测量倍频Nd:YAG激光器的调谐波长.     

基于FPGA的双通道旋转变压器测角系统设计

设计了用于星载设备的双通道多对极旋转变压器的角度测量系统.以获取高精度的电机旋转角度值为目的,在旋转变压器测角工作原理、误差分析以及双通道数据组合算法和测角系统软硬件设计等方面进行了研究,并选用FPGA对步进电机的角位移量进行探测与解算.为验证所设计的双通道旋变角度测量系统的精度,采用了分辨率更高的海德汉光电编码器进行...