共查询到20条相似文献,搜索用时 296 毫秒
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Dug-Bong Kim Chan-Yong Park Beom-Hoan O Hong-Man Kim Tae-Hoon Yoon 《Photonics Technology Letters, IEEE》1998,10(11):1593-1595
In this letter, we report -19-dB suppression of sidelobes in a grating-assisted codirectional coupler (GACC) optical filter, which is the lowest to the best of our knowledge. Pair grating structures has been employed to control the coupling strength with a raised cosine functional form. A unit pair grating is composed of two unit conventional gratings and the fundamental period of pair gratings is fixed at 2Λ, where Λ is the grating period of conventional GACC filter. The distance between the two gratings inside a pair grating is linearly shifted to control the coupling strength. This structure provides a spatially weighted coupling strength without any change of averaged effective optical index or propagation constant 相似文献
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对硅(Si)基波导光栅耦合器的设计与耦合性能进 行了研究。采用本征模展开法对光栅耦合器进行设计与 优化,通过实验测量了光栅的耦合性能,并对均匀光栅、自聚焦光栅和反射光栅等3种光栅 耦合器的耦合 性能进行了比较,耦合效率分别达到了达到47.86、56. 36和48.98%,自聚焦光栅可以有效改善光纤到 光纤的传输效果,耦合效率提高了8.5%。通过实验测量了基于耦合光 栅技术的Si基条形波导和槽型波导的 传输损耗,结果显示,条形波导和槽型波导的传输损耗分别为2.34d B/cm和6.31dB/mm。 相似文献
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提出了一种由金属光栅和流体光波导结构组成的,基于表面等离子波耦合的光栅耦合器。利用光栅的衍射效应,将金属光栅与介质分界面之间产生的表面等离子波耦合到流体光波导中,并且能够沿着流体光波导稳定地向前传播。通过采用基于有限时域差分算法的FDTD Solutions软件对光栅耦合器进行了参数优化及特性分析,通过优化使该结构在650 nm波长下的耦合效率达到56%。此外,由于该结构对TE偏振光和TM偏振光的选择比达到70∶1,因此具有偏振器的功能。同时由于TE偏振光耦合频谱的频带宽度仅为20 nm,该结构还具有窄带滤波的作用。此外,还研究了光栅结构参数、入射角以及流体折射率对耦合频谱的影响。 相似文献
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近年来,片上光子集成技术备受关注并飞速发展,但在光纤与芯片、芯片与芯片上实现高效、高可靠性的光耦合仍是难题。光栅因其制作简单,位置灵活,对准容差大及可实现片上测试等一系列优点而备受研究者的关注。目前在绝缘体上硅(SOI)平台和绝缘体上铌酸锂(LNOI)平台上已开发出大量的光栅耦合器件,并获得较高的耦合效率和大带宽。该文主要介绍光栅耦合器的工作原理和主要性能指标,阐述了均匀光栅、倾斜光栅、闪耀光栅和切趾光栅耦合的特点及现阶段进展,并对具有代表性的一维光栅性能指标进行了比较。结果表明,分布式布喇格反射镜和金属反射镜可有效地提升光栅耦合效率。此外,该文还介绍了基于LNOI平台的几种光栅耦合器,其可帮助研究者们梳理光栅耦合器的发展历程、研究现状及各耦合器的特点,为未来研究提供一定的参考。 相似文献
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为了实现横截面尺寸为50 m50 m的聚硅氧烷聚合物光波导的耦合转向问题,设计了一种表面覆盖高折射率包层的多层蚀刻光栅耦合器。首先,分析了影响聚合物波导光栅耦合器耦合效率的结构因素;然后,采用在光栅表面蚀刻高折射率层的方法,提高了聚合物波导光栅耦合器的耦合效率;接着,对不同的周期(范围:100~4 000 nm)和不同的蚀刻深度(范围:0~50 000 nm)进行排列组合,形成不同的光栅结构,基于时域有限差分法编写程序,遍历所有情况,得到不同光栅结构下的光场情况以及其耦合效率,找到使耦合效率最大的周期以及蚀刻深度。最后,设计了多层蚀刻的光栅耦合器,进一步提高耦合效率。当蚀刻深度为5 000 nm,光栅周期为2 600 nm时,带高折射率层的聚硅氧烷聚合物光波导均匀光栅耦合器的耦合效率达到最大,为17.2%。采用多层蚀刻的方式,对结构进行优化,其耦合效率能达到37.4%。为聚硅氧烷聚合物光波导在光互连中的实际应用提供了理论依据。 相似文献
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Pseudoreversibility condition for minimizing radiation loss at discontinuities of coupled waveguides
T.A. Ramadan R.W. Cohn 《Photonics Technology Letters, IEEE》2003,15(1):63-65
A design condition is derived for lossless discontinuities of coupled waveguides by finding solutions, which satisfy time reversibility of guided modes. The derived condition is used as a bound for minimizing radiation loss. Even when there is strong coupling between guided modes, the radiation loss can be minimal. A comparison between different grating designs in a 2 /spl times/ 2 backward coupler demonstrates that two coherently coupled gratings can significantly reduce radiation loss, as compared to a single grating. 相似文献
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We report a low-cost manufacturing approach for fabricating monolithic multi-wavelength sources for dense wavelength division multiplexing(DWDM)systems that offers high yield and eliminates crystal regrowth and selective area epitaxy steps that are essential in traditional fabrication methods.The source integrates an array of distributed feedback(DFB)lasers with a passive coupler and semiconductor optical amplifier(SOA).Ridge waveguide lasers with sampled Bragg side wall gratings have been integrated using quantum well intermixing to achieve a fully functional four-channel DWDM source with 0.8 nm wavelength spacing and residual errors<0.13 nm.The output power from the SOA is>10 mW per channel making the source suitable for use in passive optical networks(PONs).We have also investigated using multisection phase-shifted sampled gratings to both increase the effective grating coupling coefficient and precisely control the channel lasing wavelength spacing.An 8-channel DFB laser array with 100 GHz channel spacing was demonstrated using a sampled grating with twoπ-phase-shifted sections in each sampling period.The entire array was fabricated by only a single step of electron beam lithography. 相似文献
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Grating coupling between vertically integrated waveguides via supermode was discussed and demonstrated. Two thin-film waveguides with grating couplers were stacked on a substrate. A guided wave in one waveguide is converted by a grating coupler to a supermode propagating contradirectionally, and then converted by another grating coupler to a guided wave in the other waveguide. The coupling shows high wavelength selectivity, and the wavelength-division add/drop multiplexing function can be combined. A demonstrator was designed and fabricated. Theoretically predicted coupling efficiency was almost 100% with wavelength selectivity of 2 nm, while the experimentally obtained value was 40% in the efficiency and 1 nm in the selectivity 相似文献
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WEI Song LIU Chang QIN Houyun LIU Yiming CHEN Changming WANG Hongbo ZHAO Yi 《光电子快报》2021,17(10):598-603
In this work, the light coupling efficiency of organic light-emitting diode (OLED) and polymer optical waveguide integrated device was improved by the grating coupler. To maximize light coupling efficiency, the grating coupler was optimized by finite-difference time-domain (FDTD) method. Based on the simulation results, the grating coupler was fabricated via laser interference lithography process and an OLED was integrated on the surface of it. Comparing the integrated devices without and with grating coupler, light coupling efficiency of the grating-based integrated device was improved by about 5%. The proposed integrated device has the potential application for low-cost and flexible monolithic optical sensors. 相似文献
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A multilevel grating coupler based on silicon-on-insulator (SOI) material structure is proposed to realize the coupling between waveguide and waveguide or waveguide and fiber. This coupler is compatible with the current fabrication facilities for complementary metal oxide semiconductor (CMOS) technology with vertical coupling. This structure can realize coupling when the beams with transverse electric (TE) polarization and transverse magnetic (TM) polarization are incident at the same time. The influences of the grating coupler parameters including wavelength, the thickness of waveguide layer, the thickness of SiO2 layer and the number of steps on the TE mode and TM mode coupling efficiencies are discussed. Theory researches and simulation results indicate that the wavelength range is from 1533 nm to 1580 nm when the TE mode and TM mode coupling efficiencies are both more than 40% as the grating period is 0.99 μm. The coupling efficiencies of the incident TE and TM modes are 49.9% and 49.5% at the wavelength of 1565 nm, respectively, and the difference between them is only 0.4%. 相似文献
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A new radiation-type waveguide-to-waveguide coupler is proposed. The coupling is realized through gratings embedded on the dielectric waveguides involved. Compared to the conventional hybrid-mode coupler, this type of coupler has advantages in that the two waveguides can be quite dissimilar as well as being separated by large distances. It is demonstrated that the coupling performance of this radiation-type coupler can be enhanced significantly by using photonic bandgap (PBG) structures 相似文献
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用于高功率侧向泵浦的透射光栅耦合器 总被引:1,自引:0,他引:1
提出一种用于侧面泵浦大功率双包层光纤(DCF)激光器的双凹槽、双槽深的透射光栅耦合器,它可以被直接制作在DCF的侧面内包层上,以实现大功率的激光泵浦。利用严格的电磁场衍射理论对这种结构进行分析,并且通过结合一种梯度优化的拟牛顿算法(quasi-Newton methods)和微型遗传算法(micro-genetic algorithm)对这种结构进行优化,当侧面入射泵浦光分别为TM和TE偏振时,能实现的最大耦合效率分别为81.2%和79.7%,而且选择合适的参数可以做到偏振不敏感,对非偏振光的最大耦合效率可达72.4%,3种情况下光栅耦合器材料的折射率均大于1.8。对光栅的各个结构参数的制作容差γ、LD阵列的出射波长的漂移以及泵浦光的入射角度θ对耦合效率η的影响也进行了分析。 相似文献
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Based on mode-coupled theory, a Bragg grating assisted mismatched fiber coupler is analyzed theoretically. At the same time, a detailed numerical analysis on transmission characteristics of the coupler is carried out when it considers the arcs of two fibers in the coupling region of the coupler or not, and the optimized design on the Bragg grating assisted mismatched fiber coupler for wavelength-division multiplexing/ demultiplexing is proposed. 相似文献
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Shams-Zadeh-Amiri A.M. Jin Hong Xun Li Wei-Ping Huang 《Quantum Electronics, IEEE Journal of》2000,36(12):1421-1430
We describe a systematic method for obtaining the coupling coefficients due to diffraction orders less than the grating order of second- and higher order resonant complex gratings in a multilayer structure. This method is based on an improved Green's function, and its distinguishing feature is its use of the transfer matrix method to simplify the theoretical analysis for obtaining the Green's function in multilayer structures. More importantly, it is also shown that by introducing gain or loss in second- and higher order resonant gratings, the range of controlling the total coupling coefficient becomes wider than those in first-order complex gratings or second order index gratings. Concepts like in-phase and anti-phase gratings are generalized in this type of grating. Finally, guidelines for designing complex-coupled DFB lasers with second- and third-order grating are also presented 相似文献
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Schrauwen J. Van Laere F. Van Thourhout D. Baets R. 《Photonics Technology Letters, IEEE》2007,19(11):816-818
We have designed and fabricated an efficient grating coupler for coupling light between optical fibers and silicon-on-insulator waveguides. The coupler consists of 88-nm-wide slits, etched at an angle of 58deg to the surface normal. They are defined by direct etching with a focused ion beam, using iodine gas and an alumina hard mask. The measured efficiency is 46% 相似文献
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基于X-切绝缘体上薄膜铌酸锂平台,提出并设计了一种高耦合效率的切趾一维光栅耦合器。采用非晶硅覆盖层材料,结合亚波长光子晶体等效方案和遗传算法增强光栅耦合效率。在中心波长1550 nm处,光栅的峰值耦合效率为-1.08 dB,通过引入底部金属反射镜可进一步提高至-0.53 dB,其1 dB带宽约为61 nm。 相似文献
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The ray-optics approach based on the rigorous coupled wave theory, called rigorous ray-optics method (RROM), is developed for the calculation of backward coupling coefficients of grating waveguide devices. The coupling coefficients of several grating structures, such as rectangular, sinusoidal, triangular, and trapezoidal shapes, are evaluated by the RROM, and they are compared with those obtained by two conventional methods of the ray-optics method (ROM) and the coupled-mode method (CMM). In the case of rectangular gratings, the coupling coefficients are evaluated in more detail by varying grating depth and duty-cycle. We have found that the RROM gives us more exact solutions for the backward coupling coefficients of even arbitrary shapes of diffractive grating waveguides than the other two conventional methods 相似文献