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1.
Size influence on the propagation loss induced by sidewall roughness in ultrasmall SOI waveguides 总被引:2,自引:0,他引:2
F. Grillot L. Vivien S. Laval D. Pascal E. Cassan 《Photonics Technology Letters, IEEE》2004,16(7):1661-1663
Silicon-on-insulator (SOI) optical waveguides with high electromagnetic field confinement suffer from sidewall roughness which is responsible for strong scattering effects. This letter reports a numerical investigation on the size influence of ultrasmall SOI waveguides on the propagation loss due to sidewall roughness. It is shown that for a size smaller than 260 /spl times/ 260 nm the roughness-induced propagation loss decreases. As the optical mode confinement is reduced, a very low loss light coupling from and to a single-mode fiber can be achieved with propagation loss as low as 0.5 dB/cm for a 150 /spl times/ 150 nm cross-sectional waveguide. 相似文献
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Out-of-plane losses of line-defect photonic crystal waveguides 总被引:2,自引:0,他引:2
A numerical model is presented for computing the out-of-plane losses of a general class of two-dimensional photonic crystals superimposed. onto a slab confinement structure. The usefulness of this model is demonstrated by calculating the propagation loss of a single-row-defect waveguide composed of hexagonal air holes etched into two different slab structures. The results are interpreted in terms of a simple coupled-mode-theory picture in which loss is due to resonant coupling between the fundamental and certain radiative slab modes. These calculations show that low-loss photonic crystal waveguides should be possible by carefully designing the slab waveguide 相似文献
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We have designed and fabricated waveguides that incorporate two-dimensional (2-D) photonic crystal geometry for lateral confinement of light, and total internal reflection for vertical confinement. Both square and triangular photonic crystal lattices were analyzed. A three-dimensional (3-D) finite-difference time-domain (FDTD) analysis was used to find design parameters of the photonic crystal and to calculate dispersion relations for the guided modes in the waveguide structure. We have developed a new fabrication technique to define these waveguides into silicon-on-insulator material. The waveguides are suspended in air in order to improve confinement in the vertical direction and symmetry properties of the structure. High-resolution fabrication allowed us to include different types of bends and optical cavities within the waveguides. 相似文献
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Sugimoto Y. Ikeda N. Carlsson N. Asakawa K. Kawai N. Inoue K. 《Quantum Electronics, IEEE Journal of》2002,38(7):760-769
An AlGaAs-based near-infrared 2-D photonic crystal (PC) with an air-bridge structure featuring defect waveguides has been developed. For the sample without defect waveguides, measurements of the optical transmission characteristics in the wavelength range from 850 nm to 1100 nm showed a deep attenuation due to a bandgap with 30-35 dB attenuation and transmittance of nearly 100% for the guided modes. Optical propagation properties of defect waveguides were obtained by two methods: measurements of transmission spectra and plan-view observations of the optical beam trace along the waveguide with an infrared-vidicon camera. 3-D finite-difference time-domain simulations for the band structure and transmission spectra in the air-bridge slab with and without defect waveguides have revealed the appearance of four defect propagation modes specific to the defect waveguide, between two slab modes for the defect-free photonic crystal slab. These defect modes were experimentally identified in the measured transmission spectra 相似文献
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A low loss photonic crystal(PhC) waveguide having rectangular air holes in Si core is proposed having an average group index of 55 in the bandwidth of 1.2 THz.The possible propagation losses due to inefficient coupling are also investigated for proposed structure.It is found that high transmission is obtained for a broad bandwidth from the output of the finally designed heterogeneous waveguide consisting of a slow liquid crystal infiltrated PhC waveguide surrounded by fast PhC waveguides on both sides. 相似文献
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光子晶体光波导由于其优越的光子局域化性能,因此可以实现任意的弯曲,从而大大减小了集成光路的体积.特别是以SOI材料为基础的光子晶体光波导以其小型化、低损耗的优势而备受人们的关注.介绍了几种类型的SOI基光子晶体光波导,并探索了其潜在的应用前景. 相似文献
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分析了在 1 550 nm 波长下超薄金属膜(金膜厚t=10 nm)V-型槽等离子波导间长程沟道等离激元导模的定向耦合。通过计算不同波导间距下的模式分布,得出了定向耦合器中奇、偶模有效折射率实部和传播长度随波导间距的变化情况,并进一步计算了相邻波导间的耦合长度、最大串扰与波导间距的关系曲线。计算结果表明:在波导间距较小时,耦合长度小于各模式的传播长度,随着波导间距的增加,耦合长度随之增加,最大串扰随之减小。对超薄金属膜V-型槽等离子波导的定向耦研究在集成光路的实际应用中具有重要的价值。 相似文献
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Out-of-plane scattering in photonic crystal slabs 总被引:1,自引:0,他引:1
Ogaerts W. Bienstman P. Taillaert D. Baets R. De Zutter D. 《Photonics Technology Letters, IEEE》2001,13(6):565-567
Photonic crystal slabs combine a slab waveguide with an in-plane photonic crystal. Light is then confined in-plane by the photonic crystal and out-of-plane by the slab waveguide. The etched structures will cause light to scatter out of the waveguide plane. We studied the out-of-plane scattering losses using a two-dimensional approximation of this three-dimensional structure, with etched slots instead of holes. Our simulation techniques include mode expansion with perfectly matched layer absorbing boundary conditions. We show that the losses increase with higher index contrast, but that with very high-index contrasts light can be coupled into lossless Bloch modes 相似文献
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The Bloch mode propagation through the chirped periodical structure is defined by its local dispersion relation. In a slowly varying structure its time delay is the integral of the local inverse group velocity along the propagation direction. The integration can be strongly simplified for linearly chirped structures if the assumption is made that the local dispersion relation is just a scaled and shifted version of the dispersion relation at the input. This assumption leads to exact solutions for the structures with locally uniaxial deformation and provides a good approximation for arbitrary structures with small chirps. The approach is demonstrated for high index contrast chirped Bragg mirrors and complicated photonic crystal waveguide structures, including coupled waveguides and a slow group velocity waveguide. 相似文献
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Galli M. Bajoni D. Belotti M. Paleari F. Patrini M. Guizzetti G. Gerace D. Agio M. Andreani L.C. Peyrade D. Chen Y. 《Selected Areas in Communications, IEEE Journal on》2005,23(7):1402-1410
The dispersion of photonic modes in one-dimensional (1-D) and two-dimensional (2-D) patterned silicon-on-insulator (SOI) waveguides, also containing line defects, is fully investigated both above and below the light line. Quasi-guided (radiative), as well as truly guided modes are probed by means of angle- and polarization-resolved microreflectance and attenuated total reflectance measurements. For the 1-D case, the sharp resonances observed in reflectance spectra are analyzed in terms of the Airy-Fano model, and the measured linewidths are shown to be very close to theoretical predictions. In the 2-D lattices containing W1 line defects the presence of a supercell repetition leads to the simultaneous excitation of defect and bulk modes which are folded in a reduced Brillouin zone. The measured dispersion is in very good agreement with full three-dimensional calculations based on expansion on the waveguide modes, indicating that a deep understanding of the propagation properties of patterned SOI waveguides is achieved. 相似文献
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Zimmermann J. Kamp M. Schwertberger R. Reithmaier J.P. Forchel A. Marz R. 《Electronics letters》2002,38(4):178-180
Very efficient light transmission over a length of several millimetres through linear photonic crystal slab waveguides, patterned into an InGaAlAs waveguiding layer on InP substrate, is demonstrated. Quantitative evaluation of the light propagation in these waveguides, using the Fabry-Perot resonance method, yields a minimum loss of 1.6 dB/mm, for a waveguide with seven missing rows at 1550 nm wavelength 相似文献
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通过考虑腔中的自发拉曼散射,提出一种新的绝缘体上硅(SOI)波导拉曼激光器物理模型。仿真结果表明该模型能较好地描述其小信号输出特性,实现对该类激光器的快速分析、设计与优化。利用模型对基于多种SOI波导的拉曼激光器进行分析,结果表明室温下只有采用拥有较大拉曼系数,较小线性损耗和较短的有效载流子寿命的SOI波导才能使拉曼激光器达到阈值。提出采用优化SOI波导截面几何尺寸的方法来降低有效载流子寿命,进而提高整体拉曼增益。结果显示该方法可大幅提高SOI波导拉曼激光器的输出功率和能量转换效率。 相似文献
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飞秒激光直写玻璃波导是快速制备三维集成光子芯片的一种重要手段,波导有效折射率的准确测量对于设计光子器件意义重大。设计并制备了一种断臂马赫-曾德尔干涉仪(MZI)结构对玻璃波导有效折射率进行原位精密测量。激光在断线区域和波导内的有效折射率不同,在传输相同长度下产生一定的相位差,最终导致不同的干涉结果。对断臂MZI结构的相位干涉结果进行处理,得到激光直写玻璃波导的有效折射率为1.504+7.7×10?4。利用RSOFT软件光束传播算法对器件进行模拟仿真,仿真结果与实验吻合良好。该精确测量玻璃波导有效折射率的方法对于提升光子芯片设计与制造能力具有重要意义。 相似文献
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We discuss the effects of waveguide geometry on the radiation loss of tightly curved multimode dielectric waveguides. Three waveguide geometries are investigated: a ridge waveguide, a buried waveguide, and an interdiffused waveguide. We compare the effective index method with both semi- and full-vectorial method-of-lines analyses for these waveguide geometries. This comparison shows that the effective index method is accurate for curved waveguides except where the outer confinement region is in cut-off or, in the case of TM-polarization, for the ridge waveguide. In the latter case, the full-vectorial method-of-lines predicts a resonant feature of the TM-mode radiation loss of curved ridge waveguides; this is not predicted by either the semivectorial method-of-lines or the effective index method 相似文献
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为实现长距离传输及亚波长尺度的模式限制,在传统介质加载型表面等离子结构的基础上,设计了一种微孔介质加载混合表面等离子体波导,采用时域有限差分法(FDTD)对该波导模式场分布及传输特性进行了相应的研究。研究表明所设计的波导结构具有较强的局域场限制,通过在孔内填充增益介质,使混合等离子体波导的传输损耗得到了补偿,输出端的表面等离子激元实现了增益放大。结果表明,通过调整波导的几何参数和电磁参数,可以显著提高波导的场限制,降低波导本身的损耗,其中当孔与金属之间距离为44 nm时,波导的损耗达最小约为-13 dB/m。这一设计可以为光子器件集成提供一定的理论和实验借鉴价值。 相似文献
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Optical rib waveguides with rib heights of 3.17 and 7.67 microns with various widths have been formed in separation by implantation of oxygen (SIMOX) based silicon-on-insulator (SOI) structures. The effect of waveguide rib etch depth, width, and interface roughness on loss and mode characteristics have been studied at wavelengths of 1.15 and 1.523 microns. The experimental results support the hypothesis that certain rib dimensions can lead to single mode SOI waveguides even though planar SOI waveguides of similar multimicron dimension are not single mode. Mode loss was found to be strongly dependent on interface roughness and mode confinement 相似文献
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《Lightwave Technology, Journal of》2009,27(14):2642-2648