提出了光纤光栅啁啾化传感概念和传感机理,将光纤光栅微观分解为栅区长度范围的许多具有独立感知能力且彼此关联的有效作用子栅集,表述了有效作用子栅集与待测环境场空间梯度分布之间的对应关系,从而较好地解释了光纤光栅啁啾谱产生的内在机理。理论推导并实验验证了光栅啁啾谱各谱参量(波长、带宽和反射光强)与待测环境场(温度和应变)之间的对应关系,为利用单一光纤光栅实现多参量同时区分测量、任意非均匀空间分布场传感提供了科学有效的解决方法。

The characteristics of coherent coupling in Mach-Zehnder erbium-doped fiber laser cavity are experimentally studied. By virtue of a seemly controlling of length difference between two interferometric arms, the obtained comb-like spectrum of interferometer resonator with a period of 0.06 nm commendably agrees with the theory of self-organization coherence. The coherent output exits from the output mirror of a fiber Bragg grating with 4.5% reflectivity. A high coherent combining efficiency of 94% is obtained. Investigation on characteristics of the leak power opens out self-organization mechanism in Mach-Zehnder composite cavity.

Germanium doping in silica can be used as a method for nonlinearity enhancement. Properties of the enhanced nonlinearity in photonic crystal fiber (PCF) with a GeO2-doped core are investigated theoretically by using all-vector finite element method. Numerical result shows that the nonlinear coefficient of PCF is greatly enhanced with increasing doping concentration, furthermore, optimal radius of the doped region should be considered for the desired operating wavelength.

We designed a novel and low switching-power all-optical fiber switch. The highly nonlinear photonic crystal fiber (PCF) and the bidirectionally pumped Er3+ doped fiber amplifier are inserted into the Sagnac loop mirror simultaneously. Therefore, the symmetry of the loop is broken, and the switching function is realized for the phase shift of the reversely propagating signal. The theoretical analysis shows that the switching power is inversely proportional to the product of the amplifier gain and the PCF nonlinear coefficient. In the experiment, 40 mW switching power and 15.9 dB switching extinction are obtained, furthermore, the transmission of signal light is cosine proportional to the peak power of the pump pulse. The experimental result agrees well with that from theory.

利用光束传播法对带隙型光子晶体光纤(photonic crystal fiber，PCF)的泄露谱进行了数值分析．结果表明：PCF泄露谱往往具有多个带隙；泄露谱对PCF结构的变化异常敏感，泄露峰值波长和带隙波长不但与空气孔周期有关，还受空气孔直径的影响；由于PCF的空气孔内可填充液晶，泄露特性对液晶折射率的变化极其敏感，当液晶折射率增大时，峰值泄露波长和带隙波长都向长波漂移．

利用光纤光栅作为基本传感元件，设计研制了一种基于轮辐式压力盒装置的新型光纤光栅压力传感器．常温下在0～30KN的范围内，其测量线性度达到99．91%，灵敏度达到22N，且响应速度快．与其它类型的光纤光栅压力传感器相比，轮辐式光纤光栅压力传感器具有更大的测量范围、更高的抗干扰能力，并且由于光纤光栅本身的波分复用特性，可以很方便地构成压力传感网络进行多种物理量、多点的测量．实验表明：本传感系统具有结构简单、操作方便、滞后小、重复性好、结构高度小、重量轻等优点，在桥梁、大厦等超大型建筑以及大型管道等的检测与监测方面将会有更为广阔的应用前景．

Tunable dual wavelength erbium-doped fiber laser (EDFL) with stable oscillation at room temperature is proposed and demonstrated. This laser utilizes a Bragg grating fabricated in a high birefringence fiber as the wavelength-selective component, and then achieves the stable dual wavelength oscillation by introducing the polarization hole burning effect. Furthermore, by applying lateral strain upon the fiber Bragg grating (FBG), the space of the laser dual wavelengths can be tuned continuously.