Nonlinear optical fiber resonator: Optical fiber bistability

The linear and nonlinear charecteristics of verious optical fiber loop resonators have been processed uniformly using transmission matrix method. It is pointed that in nonlinear operation condition each of those optical fiber loop resonators may be used to make an all-optical fiber bistability device. The configuration, charecterictics and threshold of verious Er-doped fiber loop bistability devices have been calculated, analysised and compared, and the design principle of those devices has been given. Supported by the National Natural Science Fundation of China Zhang Yuancheng: born in Aug. 1938, Professor     

E r 3+ -doped fiber optical bistability by Ar+-laser

Under The nonlinear optics condition the all-fiber optical bistability operation has been realized in an all-fiber resonator consisted of Er-doped fiber and optical fiber couplers. The experimental bistability threshold is consistent with the theory. Supported by National Natural Science Foundation of China Song Qian: born in Aug. 1937. associate professor     

1.55 μm wavelength operation of E r 3+ -doped optical fiber bistability

An all-optical all-fiber optical bistability operation has been realized in an all-fiber cavity consisted with Er-doped fiber and optical fiber-loop miroors. The experimental bistability threshold is consistent with the theory. Foundation item: Supported by the National Natural Science Foundation of China (69487007) Biography: Song Qian (1937-), female, Professor. Research direction: nonlinear optics and all-optical communication.     

Er-doped fiber optical bistability without cavity

The observation of increasing absorption nonlinearity and bistability without cavity in Er-doped fiber is reported. The operation power is low (submilliwatts). The operation mechanism is analyzed. Supported by the National Natural Science Fundiation of China Zhang Yuancheng: born in Aug. 1938. Professor     

Optical switching and digital signal amplification using an optical fiber grating OBD

It is proposed that an optical fiber grating bistability device may be used for an all-optical switching or an all-optical digital signal amplifier with low power and high speed. The principle, characteristic and parameter are analysed, and some design ideas are given. Supported by National Natural Science Foundation of China Song Qian: born in Aug. 1937, Professor     

Digital optical signal amplifier using an Er-doped fiber optical bistable device

The principle and charecteristics of verious digital optical signal amplifiers using Er-doped fiber optical bistability devices have been discussed. Optical signal gain and its variation with the parameters of the devices with constant or pulse optical bias have been calculated, and the design principle of those devices has been given. Supported by the National Natural Science Fundation of China Zhang Yuancheng: born in Aug. 1938, Professor     

掺Er~（3＋）光纤的光学双稳与多稳的相干控制

本文研究掺Er3＋光纤系统中的光学双稳和多稳,定性分析了双稳态的形成机理.通过理论衍生公式对系统特性进行拟合,在改变相干场的拉比频率和耦合方式的情况下,对系统的双稳与多稳能进行有效的控制.     

窄线宽单频线偏振掺铒光纤环形腔激光器

报道了利用在未泵浦掺铒光纤中,驻波饱和吸收诱发的自写入光纤光栅的窄带滤波特性及反射波长自适应特性,并通过在腔中置入光纤起偏器,使掺铒光纤环形腔激光器产生单频线偏振激光输出,其线宽在0.75KHz以下,输出光具有典型的光学双稳态特征.     

30Hz单模超窄线宽光纤激光器

介绍利用光子注入锁模技术在掺铒光纤激光器上实现了超窄线宽单模激光输出;对光子注入锁模技术压缩激光线宽的原理进行了理论分析,讨论了饱和吸收形成的瞬态光纤光栅的参数对激光线宽产生的影响,实现了高边模抑制比的激光输出. 在实验中,通过调节泵浦功率,获得了稳定的单纵模及多纵模激光输出,测量显示输出激光的线宽为30Hz,输出最大功率可达2mW,多纵模时自由光谱范围FSR为1.875kHz.     

掺铒光纤激光器线宽压缩技术的研究

研究掺铒光纤激光器上实现的超窄线宽单模激光输出. 对复合环形腔压缩激光线宽的原理进行了理论分析,讨论了有源复合环形腔参数对激光理论极限线宽产生的影响,并对影响激光线宽的关键参数进行了实验验证,获得了稳定的单纵模激光输出,其线宽小于100Hz,输出最大功率可达2.779mW.     

Absorptive nonlinearity in Er-doped optical fiber

Optical absorptive nonlinearity in Er-doped optical fiber has been discussed and measured at the window wavelength 1.55 μm for optical communications firstly. It is proposed that the mechanism of this absorptive nonlinearity is the induced absorption. The first order nonlinear absorptive coefficient and the imaginary part and the complex value of the third-order susceptibility at that wavelength are obtained from the measured absorptive nonlinearity. Foundation item: Supported by the National Natural Science Foundation of China (69487007) Biography: Song Qian (1937-), female, Professor. Research direction: nonlinear optics and all-optical communications.     

Dispersive nonlinearity in Er-doped optical fiber

Optical dispersive nonlinearities in Er-doped optical fiber are discussed and measured at the third window wavelength 1.55 μm for optical communications firstly. The experimental method, which is developed by us, is based on dynamic scanning for fixed-point-interference (DSFPI) of two fiber beams. The real part and complex value of the third-order susceptibility at the wavelength are also obtained from the measured Kerr coefficient and nonlinear-absorption coefficient reported elsewhere. Foundation item: Supported by the National Natural Science Foundation of China(69487007) Biography: SONG Qian(1937-), female, Professor. Research direction: nonlinear optics and all-optical communications.     

Measuring Fiber Orientation in Nonwoven Fabrics by Laser Scattering Method PartⅠ Principle and Instrumentation

The scattering performance of a parallel laser beam onthe parallel fiber model and nonwoven fabrics are studiedin detail. A device of computer - program - controlledsystem for measuring laser scattering intensity - angledistribution function of fiber assemblies is set up, and themeasuring condition for distingulslhing the fibers ar-ranged at different directions is carried out. The materi-als of two categories, the models of fiber assembly andnonwoven fabrics made with varied processing methods,are studied. The analysis and experiments show that thefiber orientation distribution functions in the 2 - dimen-sional fiber assemblies can be sensitively determined bylaser scattering method.     

城市微区电波传播特性研究

阐述了一种三维电波传播模型来预测城市环境下的传播损耗．该模型建立在几何光学理论和几何绕射理论的基础上,模型考虑了地面和墙壁的反射,建筑物墙角和屋顶的绕射,计算出非视距区域的路径传播损耗     

基于光纤光栅的可调谐光纤激光器

利用光纤光栅作为调谐装置研制了可调谐的光纤激光器 . 调谐装置简单, 性能稳定, 激光器输出波长在17 nm范围内连续可调, 输出功率大于1 mW,激光谱线线宽小于0.1 nm.     

用于测量金属板厚的电光双稳光纤传感法

光纤传感法测量金属薄板厚度中,引入了电光双稳装置,以增强光强的稳定性、提高测量精度．实验表明,干涉法不宜采用多模光纤,而改用反射式强度调制型多模光纤传感器,亦可得到位移和光强的关系曲线以及满意的测量结果．     

光纤Bragg光栅的制作及其应用

光纤Bragg光栅是一种新型的光无源器件,伴随着制作技术的成熟,已成为当今的研究热点问题。根据学校对光纤Bragg光栅所开展的研究,该文介绍了光纤Bragg光栅的制作方法、在光纤激光器中的应用以及光纤Bragg光栅传感器测重实验。指出高校应紧紧围绕科技前沿研究开设实验,以达到开阔学生视野,培养社会急需高科技人才的目的。     

高次模碳纤维微波加热装置的设计与实验

为了使T300碳纤维达到微波石墨化的反应温度,需要对其进行微波加热实验。设计了一种基于TM_(110)高次横磁波模式的碳纤维微波加热装置,该装置是一种圆柱形谐振腔,腔体两侧分别存在一个轴向电场最大值区域,理论上可以同时加热多束碳纤维。为了保证碳纤维的加热效率,在设计时需要同时兼顾腔体的谐振频率和阻抗匹配特性。使用仿真软件优化了耦合点的具体位置,并对优化后的圆柱形谐振腔进行了多物理场的耦合仿真。仿真结果表明:出口处碳纤维的表面温度最高,且靠近耦合点的左侧碳纤维温度高于右侧。实验结果与仿真结果较为吻合,验证了碳纤维微波加热的可行性和装置的有效性。     

光子晶体光纤光栅在传感器系统中应用研究

光子晶体光纤光栅是一种新型的无源器件,可广泛用于光纤通信系统、光脉冲压缩、传感器及滤波装置中.采用耦合模理论对光脉冲在光子晶体光纤光栅中传播进行分析,给出光子晶体光纤光栅的制作方案,提出了光子晶体光纤光栅在压力传感器、折射率传感器、应变传感器和射流传感器等方面的具体应用.光子晶体光纤光栅对温度的敏感性比传统单模光纤传感器要低2至3个数量级,光子晶体光纤光栅传感器系统不需要温度补偿,传感器系统更为简洁而具备充分的优越性.     

一种基于光纤光栅的窄线宽激光器

利用光纤光栅作为选频装置研制了窄线宽的环形腔光纤激光器。结果表明,选频装置简单、性能稳定、激光器输出波长在1 550 nm附近,谱线线宽小于0.1 nm。