Tunable photonic crystal coupled-cavity laser

We report the development of a tunable photonic crystal coupled-cavity laser diode based on InP. The laser consists of two photonic crystal channel waveguides that are coupled through a photonic crystal mirror segment in /spl Gamma/-M direction. The cavity lengths define the respective mode spacings in the cavities. The tuning characteristics of the device are compared with results obtained from a transfer matrix model. Quasi-continuous tuning is achieved in a 29.6-nm window with 36 wavelength division multiplexing channels spaced 0.8 nm apart (ITU grid). The simplicity of fabrication and promising output characteristics should make this tunable laser design an interesting source for monolithic integration into highly integrated photonic circuits.     

双包层光子晶体光纤激光器研究进展

光子晶体光纤(PCF)具有许多传统光纤难以实现的诸多优良特性,以光子晶体光纤为增益介质的高功率光纤激光器受到了普遍关注.介绍了光子晶体光纤及由其构成的光子晶体激光器的原理,重点介绍了双包层光子晶体光纤激光器国内外的最新研究进展.     

Switchable dual-wavelength erbium-doped fiber laser with a tilted fiber grating

Multiwavelength erbium-doped fiber lasers (EDFLs) have attracted considerable interests in recent years for their po- tential applications in Wavelength-division-multiplexed fi- ber communication system, fiber sensing, optical instrumentation, and microwa…     

Widely tunable complex-coupled distributed feedback laser with photonic Crystal mirrors and integrated optical amplifier

We report the development of a current-controlled widely tunable laser diode based on InP with photonic crystal mirrors and an integrated amplifier section for stabilized power output. The laser consists of three longitudinally coupled ridge waveguide cavities that are coupled through photonic crystal mirror segments. A laterally defined binary superimposed grating provides complex-coupled distributed feedback into two of the laser cavities. The wavelength can be switched over a range of 26 nm. Through adjustment of the current into a third amplifier section, the output power can be stabilized over the tuning range of the laser.     

Tunable,Gap‐State Lasing in Switchable Directions for Opal Photonic Crystals

A photonic crystal laser that is tunable throughout the visible in three‐dimensionally switchable directions is demonstrated. This photo‐pumped laser utilizes a dye‐infiltrated, single‐crystal SiO₂ opal having incomplete bandgaps. Our results support a gap‐state‐enhanced distributed feedback mechanism for lasing. Three different types of wavelength tunability are demonstrated, each applicable over a different frequency range and involving either single or multiple bandgaps. The many independent laser cavities that exist in one photonic crystal are demonstrated by simultaneously obtaining lasing in various colors and directions from an opal crystal. The observation of characteristic laser emission lines provides a new spectroscopy for characterizing intra‐gap photonic states, which may be useful for developing the photonic crystal analogues of electronic circuitry.     

二维聚合物分散液晶光子晶体的制备与研究

为了改善现有聚合物分散液晶(PDLC)光子晶体(PC)的制备方法和电光特性,利用532nm激光干涉条纹引发聚合物和液晶的混合物相分离,采用全息两次不等时曝光的方法,即第1次曝光完成后,将样品沿基板中心法线旋转60°进行第2次曝光,制备得到电可调谐的二维三角格子的PDLC-PC。实验结果表明,两次曝光的时间对聚合物和液晶的相分离程度影响很大,用偏光显微镜观察优化条件下制备得的二维PDLC-PC发现,聚合物和液晶在二维空间上呈规则的三角格子周期性分布。用波长为633nm的He-Ne激光器探测得到在未施加电压时不同晶格常数的PDLC-PC的衍射图样,并根据一级衍射的电光变化曲线,可以看到,其衍射效率可以利用电场进行有效的调节。     

Micro-fluidic photonic crystal vertical cavity surface emitting laser

The first monolithic micro-fluidic photonic crystal vertical cavity surface emitting laser (VCSEL), wherein the horizontal and vertical micro-fluidic channels lie within the VCSEL, is reported. The micro-fluidic photonic crystal VCSEL is created with two principal steps after fabrication of the VCSEL. The first step is integrating the two-dimensional photonic crystal with the VCSEL structure. The photonic crystal creates singlemode operation, and acts as the vertical micro-channels. After creating the photonic crystal pattern in the VCSEL, the oxide layer is selectively wet etched to form the horizontal channel. Preliminary results obtained from the introduction of fluid into the micro-channels are presented.     

碱金属碱土金属对Yb3+掺杂硅酸盐激光玻璃的物理和光学特性影响

高功率掺杂光子晶体光纤激光器受到国内外研究者的广泛关注,应用于掺杂光子晶体光纤纤芯的掺杂玻璃制备成为自主拉制掺杂光子晶体光纤,进而实现高功率激光器的国产化基础问题之一。通过高温熔融工艺制备了Yb3+掺杂浓度相同、基质碱金属和碱土金属成分不同的硅酸盐玻璃,计算并分析了碱金属、碱土金属对玻璃样品的物理性质、光谱性质和激光特性的影响。结果表明:Yb3+-SiO2-Li2O-MgO-CaO-BaO-Al2O3多组分硅酸盐玻璃是优质的Yb3+掺杂光子晶体光纤的纤芯材料之一,为后期制备双包层Yb3+掺杂光子晶体光纤激光器的纤芯材料提了供理论和实验依据。     

一维光子带隙光子晶体激光腔的特性分析

利用平面波展开法与时域有限差分法分析计算了一维光子带隙光子晶体腔的特性。得到了品质因子Q为2.2×106,模体积V为0.278(λ/n)3的一维带隙光子晶体腔。分析了渐变区、腔镜子区及缺陷区对腔品质因子Q和模式体积V的影响。引入渐变区、选择适量周期数及一定缺陷区长度都可以提高腔性能。该结论为设计优化一维光子带隙光子晶体腔提供了有效的理论分析依据与指导。     

光子晶体调制半导体激光器侧模

为了实现半导体激光器的单侧模稳定工作,提出了一种在激光器的脊条两侧引入光子晶体结构滤除半导体激光器高阶侧模的方法。通过调整激光器上表面的刻蚀深度、光子晶体区域的条宽和间隔来改变激光器内部的模场分布,同时结合选择性的载流子注入来增强基模的激射优势,进而减少侧模的数量。实验上制作了主脊条宽度为6 m,光子晶体周期5 m,波长1 550 nm的半导体激光器。测试结果表明:在连续工作的情况下,电流300 mA的时候,高阶侧模受到抑制,水平发散角变为10.2,证实了光子晶体结构调制激光器侧模的可行性。     

双掺Mg：Fe：LN晶体中构造光子晶格的实验研究

为了提高光子晶格的衍射效率,加快晶格写入时间,尝试在掺Fe浓度相同的双掺Mg：Fe：LN晶体（ Fe：0.03 wt.%, Mg：2.0 mol）和Fe：LN晶体（ Fe：0.03 wt.%）中分别用λ为488 nm半导体激光器和532 nm Nd：YGA固体激光器写入一维光子晶格,对比研究了两晶体内光子晶格最大衍射效率η和时间t的关系。实验结果表明,在双掺Mg：Fe：LN晶体内写入光子晶格时间比Fe：LN晶体所需时间短、衍射效率高。     

Room-temperature operation of VCSEL-pumped photonic crystal lasers

Room-temperature operation of two-dimensional photonic crystal lasers optically pumped by a vertical-cavity surface-emitting laser emitting at 860 nm is reported. The photonic crystal membrane is surrounded by air on both sides and consists of four compressively strained quantum wells as the active region. The incident threshold pump power of an approximately 2.6-μm-diameter hexagonal defect cavity laser operating at 1.6 μm is 2.4 mW     

基于光子晶体光纤飞秒激光技术的高功率紫外激光源

实验研究了一种基于大模场面积光子晶体光纤飞秒激光技术的紫外飞秒激光源.分析了群速失配下的倍频光和基频光的走离长度,并实验比较了不同长度的BBO晶体的倍频功率和效率.分别采用5 mm和0.18 mm的两块BBO晶体,在Ⅰ类相位匹配条件下,对光子晶体光纤放大器输出的脉宽为110 fs,重复频率50 MHz的1040 nm飞秒激光进行腔外二倍频(SHG)和四倍频(FHG),获得了高功率紫外飞秒激光.在20 W的平均功率抽运下,获得了8.88 W的二倍频绿光输出,转换效率为44.4%.同时获得了656 mW的四倍频260 nm紫外激光,单脉冲能量13 nJ,最高功率时二次谐波(SH)到四次谐波(FH)的转换效率为7.39%.     

光子晶体光纤及其激光器

光子晶体光纤(PCF)与普通光纤相比有着优秀的单模特性、色散特性和非线性特性。简述了光子晶体光纤的基本结构及其优点,并分析了利用光子晶体光纤制作光子晶体光纤激光器及大功率光纤激光器方面的研究进展。     

光折变晶体中共面多光束干涉研究

构用共面多光束干涉在光折变晶体中形成了对比度较大的一维、二维周期性晶格微结构。理论和实验对比研究了共面双光束和多光束在光折变晶体中会聚相干形成周期微结构的分布规律和影响因素。在相干理论的基础上,建立了具有普适性的共面多光束相干数学模型,数值模拟了n(n=1,2,3,4,5,6)束共面激光相干光场的光强分布规律。实验结果表明,干涉光场图案分布同数值模拟相吻合。实验中进一步讨论了相干系统各参数变化对干涉效果的影响,并通过全息记录在铁电铌酸锂晶体中构造出了同多光束干涉场光强分布对应的光子晶格微结构。     

在光子晶体光纤中实现波长调谐飞秒孤子脉冲输出

介绍了在光子晶体光纤中产生波长调谐飞秒光孤子脉冲的机理及研究进展,并对波长调谐飞秒孤子激光系统进行了分析和比较。     

负折射率缺陷层的一维各向异性光子晶体缺陷模特性

本文提出了负折射率缺陷层的一维各向异性光子晶体结构,利用传输矩阵的方法给出了TE波和TM波的透射率,结果表明在TE波中出现两个及多个缺陷模,TM波存在单缺陷模,两种偏振状态不同的透射波的缺陷模能分开,得出了光通过负折射率缺陷层的一维各向异性光子晶体后TE波和TM波随入射角的变化特性、随缺陷层厚度的的变化特性。这些特性用于光子晶体多通滤波、光子晶体偏振和激光谐振腔等器件的设计具有重要意义。     

光子晶体光纤出射光的相干现象

测量了光子晶体光纤的模场分布,得到了出射光的干涉条纹及其光强分布,并进行了理论分析,试验与理论分析的结果具有较好的一致性.提出了利用光子晶体光纤结构的高度可调性,使多束输出光进行相干加强,为多芯或集束式光子晶体光纤在大功率激光器、放大器及传能光纤方面的应用提供了基础.     

关注激光技术的一些发展和应用

本文阐述了激光、光纤通信、计算机控制系统的基本特点和作用,介绍了国外激光武器和激光制导的应用状况,说明了激光技术与计算机控制系统结合的重要性,并站在节能减排和保护环境的高度,预测了激光技术未来应用于电力行业的内容和前景。     

利用Padé近似理论分析光子晶体微腔结构

利用数学Padé近似理论和时域有限差分(FDTD)方法作为一种谱分析手段,研究了几种具有对称性的光子晶体微腔结构,用较短的时间序列计算得到很高的谱分辨率和精度,通过分析光子晶体微腔的缺陷模式,得到了品质因子高达10~6量级的光子晶体微腔结构,为优选光子晶体材料,提高激光器的功率转换效率提供了一定的理论依据。