Multi-wavelength fiber ring laser based on a chirped moiré fiber grating and a semiconductor optical amplifier

A simple and cost-effective multi-wavelength fiber ring laser based on a chirped Moiré fiber grating (CMFG) and a semiconductor optical amplifier (SOA) is proposed.Stable triple-wavelength lasing oscillations at room temperature are experimentally demonstrated.The measured optical signal-to-noise ratio (SNR) reaches the highest value of 50 dB and the power fluctuation of each wavelength is less than 0.2 dB within a 1-h period.To serve as a wavelength selective element,the CMFG possesses excellent comb-like ...     

Switchable Multi-Wavelength Erbium-Doped Fiber Lasers based on a Mach-Zehnder Interferometer Using a Twin-Core Fiber

A switchable multi-wavelength erbium-doped fiber ring laser based on a compact in-fiber Mach-Zehnder interferometer comb filter at room temperature is presented. The comb filter is formed by splicing a section of twin-core fiber between two single mode fibers. By adjusting the states of the polarization controller appropriately, the laser can be made to operate in stable single-, dual- and three-wavelength lasing states. The operation principle is based on spectral hole burning induced by the saturated effect and polarization hole burning.     

Analysis and Simulation of Adiabatic Bend Transitions in Optical Fibers

A low-loss criterion for bend transitions in optical fibers is proposed. An optical fiber can be tightly bent with low loss to be adiabatic for the fundamental mode, provided that an approximate upper bound on the rate of change of bend curvature for a given bend curvature is satistied. Two typical adiabatic bend transition paths, the optimum profile and linear protile, are analyzed and studied numerically. A realizable adiabatic transition with an Archimedean spiral profile is introduced for low bend loss in tightly bent optical fibers. Design of the transitions is based on modeling of the propagation and coupling characteristics of the core and cladding modes, which clearly illustrate the physical processes involved.     

用于制作光子晶体光纤的毛细管的拉制理论与实验分析

根据流体力学的相关理论建立了毛细管拉制过程的简化模型.首先通过理论计算,分析了毛细管制作中的各种工艺参量,如控制参量、设备参量、预制棒结构参量等,对最终毛细管结构的影响.在本文讨论的工艺下,毛细管结构的相对缩塌不可避免,而工艺参量的调整仅可以在一定程度上改善结构的变化.最后通过具体的拉制实验与理论计算进行了比较分析,二者取得了很好的一致性,验证了计算模型的可靠性.相关结论可推广到光子晶体光纤的制作中,有很好的工艺参考价值. 关键词： 光子晶体光纤 毛细管 制作理论 工艺参量     

半导体激光器线阵的棱镜组光束整形器和光纤耦合输出

针对半导体激光器线阵输出光束快慢轴方向光参数积不对称问题,提出并制作了基于直角棱镜片的光束整形器,其具有结构简单紧凑,制作安装容易的特点。通过数值仿真和实验对光束整形器进行了分析,研究表明整形器实现了半导体激光器线阵输出光束的对称化,并且光束经过透镜聚焦后对数值孔径为0.46,直径为200μm的光纤进行耦合,效率为53%。     

基于啁啾相移光纤光栅的滤波器设计及应用

相移光纤光栅作为透射型带通滤波器件降低了使用成本和插入损耗.在光通信和传感领域有着较高的应用价值.啁啾相移光纤光栅的透射峰波长和数量由相移点的位置和数量来确定,透射峰特性受相移量的影响.采用分段切趾的方法获得满足光通信要求的滤波特性,利用传输矩阵法分析了切趾前后透射峰特性的变化,结果表明:切趾改善了滤波器的幅度和相位响应,依据滤波器的设计要求选取不同的切趾函数以及切趾比例;切趾还大大减弱了透射峰波长和深度对相移量的敏感度,适当切趾后相移量的影响可以忽略.并提出一种应用双通道啁啾相移光纤光栅滤波器产生脉冲毫米波副载波信号的方案.     

Investigation on the intensity noise characteristics of the semiconductor ring laser

Based on the frequency-domain multimode theoretical model, detailed investigations on the noise characteristic of the semiconductor ring laser （SRL） are first performed in this paper. The comprehensive nonlinear terms related to the third order nonlinear susceptibility Z3 are included in this model; the Langevin noise sources for electric field and carrier density fluctuations are also taken into account. As the injection current increases, the SRL may present several operation regimes. Remarkable and unusual low frequency noise enhancement in the form of a broad low frequency tail extending all the way to the relaxation oscillation peak is observed in any of the operation regimes of SRLs. The influences of the backscattering coefficient on the relative intensity noise （RIN） spectrum in typical operation regimes are investigated in detail.