掺铒富硅氧化硅薄膜的光致发光

本文研究了富硅氧化硅薄膜掺入铒的发光特性．富硅氧化硅薄膜（氧含量为６０％）采用ＰＥＣＶＤ方法生长,室温下离子注入铒,经过８００℃,５ｍｉｎ的退火,在１０～３００Ｋ温度下得到较强的波长１．５４μｍ光致发光．发光强度随温度升高而下降,其温度猝灭激活能为１４．３ｍｅＶ．发光谱表明富硅氧化硅中Ｅｒ－Ｏ发光中心仍具有Ｔｄ对称性．     

掺铒光波导放大器的增益特性研究

本文用重叠因子的方法研究了 ９８０ ｕｍ波段泵浦的掺铒光波导放大器、得到了其增益的隐式解析解，在此基础上得到了泵浦阈值功率的解析表达式．详细讨论了铒掺杂浓度、泵浦功率对放大器增益的影响．     

硫系掺铒光波导在光通信的研究进展

概述了硫系掺铒光波导(EDWA)优良的材料特性及其巨大的发展前景,简述了硫系掺铒光波导结构设计及增益特性,同时对目前硫系掺铒光波导研究中存在的问题作出了总结,并对今后的研究工作也做出了进一步的展望。     

侧蚀对脊形掺铒光波导放大器净增益的影响

用有限元方法分析了脊形掺铒Al2O3光波导放大器内部信号光和泵浦光的电磁场模式分布,结合速率方程和传输方程,数值模拟了脊形Er∶Al2O3光波导放大器的净增益特性,讨论了光波导侧蚀对放大器净增益的影响.     

980nm波段泵浦的掺铒硅酸盐玻璃光波导放大器的增益特性

在忽略放大自发辐射（ASE）的情况下,考虑羟基和上转过程的影响,研究了980nm波段泵浦的铒离子注入硅酸盐光波导放大器的增益特性。详细讨论了羟基、上转过程、铒掺杂浓度和8泵浦功率对增益的影响。数值计算结果表明,上述参数的优化对提高放大器的增益是极其重要的。     

小尺寸硅绝缘体光波导损耗测量

基于法布里-珀罗(F-P)腔理论建立了一种简单有效的硅绝缘体(SOI)光波导损耗测量方法.该方法采用端面耦合,通过测试波导反射功率谱并利用傅里叶频谱信息,完成波导损耗的测量.推导中指出了无法直接利用反射谱F-P峰峰谷值求解损耗的限制因素.应用该方法实现了对刻蚀深度为750 nm和宽度为1200 nm的SOI脊形波导损耗...     

掺Er3+玻璃光波导放大器的新进展

介绍了掺稀土元素的玻璃集成光波导放大器的原理、结构和制作方法特点,同时介绍了这一领域的新进展和发展趋势。     

低损耗SOI单模脊形光波导的制备

表面散射损耗与菲涅耳反射损耗是SOI(Silicon-on-msulator)脊形光波导的主要损耗机理.通过降低光波导损耗的研究,在厚膜SOI材料上制备了长度为20 mm,插入损耗小于2.15 dB的单模脊形光波导.     

单模GexSi1—x脊形光波导的研制

通过分析和计算，得到了单模ＧｅｘＳｉ１－ｘ脊形光波导内脊高、脊宽和腐蚀满足的关系。实践证明，按照这些关系可以成功设计制作 单模ＧｅｘＳｉ１－ｘ脊形光波导。     

铒镱共掺光波导放大器的优化

本文介绍了光波导放大器的理论,分析了由于铒离子吸收截面小和铒离子浓度过高带来的聚集效应,并认为由该聚集效应引起的协同上转换和激发态吸收会限制掺铒磷酸盐光波导放大器的增益.将镱离子作为敏化剂掺入到光波导放大器中,不仅可以降低饵离子高浓度引起的聚集,而且可以有效地解决光波导的增益问题.在考虑协同上转换效应的基础上,用龙库算法研究了饵镱共掺的光波导放大器,讨论了镱离子浓度和波导长度两个主要影响因素,并且计算出了最佳的波导长度和最佳的掺镱浓度.     

Neodymium-doped tantalum pentoxide waveguide lasers

The fabrication, spectroscopic properties, and laser performance of Nd/sup 3+/-doped Ta/sub 2/O/sub 5/ channel waveguide lasers are described. Lasing is obtained at both 1.066 and 1.375 /spl mu/m with threshold pump powers as low as 2.7 mW. The rib waveguides are reactive-ion-etched into Nd:Ta/sub 2/O/sub 5/ layers formed by reactive magnetron sputtering. These high-index low-loss rare-earth-doped waveguides are fabricated on silicon substrates and offer the potential for integration with photonic crystal structures for compact optical circuits.     

Losses in tantalum pentoxide waveguides

Thin films of tantalum pentoxide for possible use as waveguides have been prepared by reactive sputtering and by thermal and anodic oxidation of sputtered tantalum films. Measurements have been made of the losses in these films for different guided modes. These results have been analyzed to determine the loss mechanism. The losses do not fit the Rayleigh scattering theory precisely and the deviation is attributed to absorption by impurities at the surface as well as in the bulk. The effects of bulk and surface loss mechanisms have been obtained and causes of these are discussed.     

Direct-bonded QPM-LN ridge waveguide with high damage resistance at room temperature

A direct-bonded 13 mm-long quasi-phase matched LiNbO/sub 3/ (QPM-LN) ridge waveguide is fabricated that exhibits a second-harmonic generation efficiency of 44%/W. The waveguide shows very high resistance to photorefractive damage at room temperature. The difference frequency generation with an efficiency of -17.6 dB in the 1550 nm wavelength band is also demonstrated.     

退火温度对高介电常数Ta2O5薄膜电学性能的影响

利用磁控溅射法在硅(Si)衬底上沉积了Ta2O5薄膜,对薄膜进行了不同温度的退火处理,并利用X射线衍射仪对薄膜的微观结构进行了分析.然后在Si的背面和介电薄膜的上面沉积Pt电极,组成了金属—氧化物—半导体( MOS)电容器,对不同温度下退火得到的薄膜制备的MOS电容器的电学性能进行了研究.结果表明,薄膜在700℃开始结...     

高速脊波导激光器寄生电容的分析

高速调制半导体激光器光源是光纤通信系统、相控阵雷达等的关键器件。高速激光器的寄生电容是影响其调制带宽的因素之一。为了减小寄生电容,针对脊波导结构激光器的电容,采用计算机模拟与实际测试相结合的方法,进行了理论分析和实验验证。结果表明,其寄生电容大小不仅与电极金属化面积有关,还与隔离沟的腐蚀深度有关。当腐蚀至波导层时,寄生电容减小到10pF以下。这一结论对实现激光器的高速调制是非常有意义的。     

低阈值电流、高量子效率脊形波导激光器

研制了低阈值电流、高量子效率670nm压缩应变单量子阱GaInP/AIGalnP脊形波导激光器。测量解理成的激光器条,腔长为300μm时,阈值电流为12．8mA,双面外部量子效率之和达到94．6％。     

脊的变化对双脊波导场图的影响分析

对称双脊波导脊的大小变化改变其传输特性参数,采用亥姆霍兹方程有限元方法计算出双脊波导主模截止波长数值,结果与文献结果对比说明计算方法精确有效,求对应的特征向量,就可得到脊波导横截面上的电场分布,从而分析脊大小变化对场结构图的影响。     

Highly reliable MIS capacitors with plasma nitridation and doubled dielectric-constant tantalum pentoxide

We studied effective thinning of metal-insulator-semiconductor tantalum pentoxide capacitors experimentally for DRAM application. First, we investigated the dielectric constant of a tantalum pentoxide film deposited and crystallized on an oxidation-resistant thick silicon-nitride film. Dependence of electrically equivalent thickness on physical thickness of tantalum pentoxide revealed an increased dielectric constant of 60, whereas the films on a silicon-dioxide film had a dielectric constant of no more than 40. To apply this increased dielectric constant to DRAM capacitors, we applied novel plasma nitridation on the surface of polysilicon. The plasma-nitrided surface showed fair oxidation resistance up to 800/spl deg/C, at which a tantalum pentoxide film fully crystallizes. The temperature was 100/spl deg/C higher than that of a conventional treatment using rapid thermal nitridation (RTN). The improved oxidation resistance enabled the increased dielectric constant as well as suppression of silicon oxide between the film and polysilicon. Consequently, effective thinning by 10% was demonstrated even on rugged polysilicon without increase of leakage current. Time-dependent dielectric-breakdown measurements revealed that the tantalum pentoxide capacitors fabricated using plasma nitridation are expected to have a lifetime three orders of magnitude longer than that of those fabricated using RTN.     

Reactively sputtered tantalum pentoxide thin films for integrated capacitors

The aim of this work was to develop a deposition process for a high-dielectric constant tantalum pentoxide for integrated capacitors. Thin films were deposited reactively on glass wafers using a radio-frequency magnetron sputtering cluster tool at various O₂/Ar flow ratios. By using 2 MeV ⁴He⁺ backscattering spectroscopy and X-ray diffraction, the films obtained showed a stoichiometric orthorhombic β-Ta₂O₅ phase at 20% O₂ in the sputtering gas flow. With low-frequency measurements (f=100 kHz), a 200×200-μm² square metal–insulator–metal (MIM) capacitor with copper electrodes and a 340-nm thick dielectric gave a capacitance density of 0.066 μF/cm², with a quality factor (Q) of 650. The value of the relative permittivity (_r) was approximately 25 determined from MIM capacitors of various sizes. The surface roughness of the 376-nm thick oxide film was found to be small: 0.255 nm. The largest measured capacitor (200×200 μm²) gave reasonable results at low frequencies. When the frequency was increased (100 kHz–20 GHz) only for the smaller capacitors (30×30 μm²) the capacitance remained constant. However, the Q values decreased of the smaller capacitors as a function of frequency. Processed tantalum pentoxide MIM capacitors possessed reasonable electrical properties below 2 GHz and good potential for further improvement.     

Wide-band waveguide and ridge waveguide T-junctions for diplexerapplications

Scattering parameters of E- and H-plane stepped waveguide and E-plane ridge waveguide stepped T-junctions are obtained using an extension of the three-plane mode matching method. An optimization process is applied to find the T-junctions and step dimensions that yield a low reflection coefficient in one of the T-junctions arms over a wide frequency band. An example of the design of a wideband T-junction diplexer is presented. The diplexer filters are inductive window waveguide filters, and are rigorously modeled using mode matching and a novel two-dimensional curve fitting method, which greatly reduces the CPU time for optimization. The diplexer optimization procedure, as well as the filter modeling method, are described. Experimental results on the optimized T-junction and the diplexer are presented; both show excellent agreement with their computed optimum results, without any adjustments or tuning