共查询到20条相似文献,搜索用时 31 毫秒
1.
A thorough and detailed characterization of annealed proton-exchanged (APE) waveguides in Z -cut LiNbO3 is described. The mode index measurements in planar waveguides as a function of wavelength and annealing time are reported, including useful analytical relations for the refractive index change, its dispersion, and the depth profile as a function of annealing parameters. Analytical expressions for the mode propagation characteristics are presented and experimentally verified with reasonable accuracy. It is shown that the planar waveguide characterization results can be used to model the channel waveguide characteristics accurately. The model provides closed-form expressions for the mode index and the mode field profile, and the theoretical results are in excellent agreement with the measured data. The technique is used to accurately predict the phase mismatch between the fundamental and second harmonic modes in frequency-doubling experiments using APE channel waveguides. An optimum waveguide geometry for which the phase mismatch is relatively insensitive to the waveguide nonuniformity was predicted and verified experimentally 相似文献
2.
A guided wave optical interconnect has been designed which reduces or eliminates clock skew by ensuring simultaneous delivery of clock pulses to chips mounted on a wafer. The interconnect consists of a multimode trunk waveguide and a set of branch waveguides, one per chip, each of which couples one mode out of the trunk waveguide. The elimination of clock skew is accomplished by taking advantage of the different group velocities of the modes inherent in multimode waveguides and suitably tailoring the propagation constants of the trunk waveguide according to the location of the respective chip on the wafer. Inverse scattering theory, specifically, the method of Darboux transformations, is used to design the refractive index profiles of the trunk waveguides, using the set of propagation constants selected during the first stage of the design as input data. It is shown that, by using transverse coupling and suitable design of the trunk and branch waveguides, efficient coupling from the trunk to the branch waveguides can be ensured. Techniques for ensuring a symmetric trunk refractive index profile are investigated 相似文献
3.
铜离子交换单步掩埋BK7玻璃波导的制备与表征 总被引:1,自引:1,他引:1
利用Cu离子交换技术制备了BK7玻璃平面光波导,在6328nm波长下,用棱镜耦合技术测量出所制备波导的有效折射率,利用反WKB方法计算并确定了平面光波导的折射率分布,通过对折射率分布进行函数拟合,发现离子交换后的样品折射率分布近似符合改进后的高斯分布,样品的折射率分布似乎是一个掩埋波导的折射率分布,求出所制备玻璃平面光波导在570℃的扩散系数De≈12133×10-14m2s。同时,对所制备波导进行了电子显微镜(EMS)和次级离子质谱(SIMS)测试,得到了铜离子在玻璃表面的浓度分布,从而证明了实验所得到的BK7玻璃平面光波导是掩埋波导。这种掩埋平面波导是由单步Cu离子交换技术得到的。 相似文献
4.
A novel filter structure which can reduce the crosstalk in cross-connection and switching in all optical networks based on dense wavelength division multiplexing(DWDM) is presented.The filter is constructed by dielectric waveguide with the waveguide boundary or the waveguide itself uncontinuous in transmitting direction.Using the concept of effective refractive index of plane waveguide system, we can get a special index profile along the wave propagation direction by alternatively changing the thickness of waveguide film or its refractive index.Having proved this kind of waveguides with filtering properties, the design principle of an example is given, which will be very useful to reduce the crosstalk in optical cross-connection and switching in all optical networks based on DWDM. This kind of filters can be easily connected with other related component. 相似文献
5.
为实现铌酸锂退火质子交换(APE)波导折射率分布的准确计算,选择含苯甲酸锂的苯甲酸缓冲液作为质子交换质子源,高温退火制作了波导样本.针对该工艺过程建立退火质子交换波导模型,包括非线性扩散模块和光学数值仿真模块,分别计算APE波导折射率及其模式有效折射率.以测得的样本波导模式有效折射率和计算的有效折射率差的均方根构建评价函数(FOM),结合遗传算法提取该工艺条件下质子扩散参数,实现了不同交换深度和退火时间波导折射率分布及其光学特性的一体化计算.实验表明:FOM小于0.001,计算折射率分布同IWKB方法测得结果吻合较好,最大偏差约0.002. 相似文献
6.
Hirono T. Kohtoku M. Yoshikuni Y. Lui W.W. Yokoyama K. 《Photonics Technology Letters, IEEE》1998,10(7):982-984
Applications to equip semiconductor phased-array wavelength demultiplexers with nonbirefringent waveguides are increasing. In several applications, the waveguides are multimodal and elimination of first-order mode excitation is required for their design. The optimized offset for eliminating the first-order mode excitation at the junction of straight and curved waveguides with a two-dimensional (2-D) structure is analyzed theoretically. We assume that the waveguide has a laterally symmetric index profile. By the perturbation method, the offset is obtained to the first order in the inverse of the bending radius. The offset is simply expressed by the effective refractive indices of the straight waveguide 相似文献
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White V. Ghodssi R. Fish G. Herdey C. Liu H. Denton D.D. McCaughan L. 《Photonics Technology Letters, IEEE》1995,7(7):772-773
We report a new method for producing graded index polymethyl methacrylate (PMMA) waveguides using optical densification by angled X-ray exposure. The resulting larger refractive index near the surface of the waveguide serves to better isolate the guided light from potentially absorbing or scattering substrates than in waveguides of constant refractive index. We calculate that a 65° angle exposure in 6-μm-thick planar PMMA waveguide shifts the peak of the fundamental mode profile ~0.5 μm away from the substrate. Consistent with this result, we measure a reduction in the propagation loss of PMMA planar waveguides on a Ni substrate from 1.5 dB/cm to 0.5 dB/cm after angle X-ray exposure 相似文献
9.
Won Jay Song Song G.H. Byung Ha Ahn Minho Kang 《Antennas and Propagation, IEEE Transactions on》2003,51(6):1185-1198
We have applied the effective index method to reduce the two-dimensional (2-D) refractive index profile into the 1-D refractive index structure and modified the wave equations to obtain the paraxial wave equations. Then, transverse electric (TE) and transverse magnetic (TM) polarized fields in the curved single-mode planar waveguides are analyzed by using the scalar beam-propagation method (BPM) employing the finite-difference method with a slab structure. The bending loss in bent waveguides is analyzed for optical fields obtained from the BPM and comparisons are made between the loss for the waveguides with various radius of curvature and refractive index difference. The outward shift of the optical field, which is generated at the connection between a straight and a bent waveguide, is obtained from the results of calculation of location of the maximum optical intensity. The transition loss can be reduced by introducing an optimized inward offset at a straight-to-bend junction. The birefringence for TE and TM polarized fields in bent waveguides is calculated from the phase difference of the optical fields. The wavelength shift due to the birefringence of TE and TM polarized fields in bent waveguides is also calculated. 相似文献
10.
Integrated optical refractometer based on waveguide bend loss 总被引:1,自引:0,他引:1
This paper reports on a refractometer, which is based on measuring the throughput of a bent channel waveguide. A new type of channel waveguide, designed in SiON technology makes the throughput strongly dependent on the refractive index of a measurand fluid. This new waveguide can be designed for any measurand refractive index range between 1.00-5 in an aqueous solution with a refractive index of n=1.37. The sensor characteristics, make this simple sensor very interesting for controlling a chemical concentration during chemical processes, e.g., in the food and beverages industry 相似文献
11.
A simple nondestructive method for determination of refractive index profile of single-mode waveguides using the measured effective refractive indexes is proposed. The method is based on the extraction of the additional data about the waveguide profile from the investigation of its evolution with the duration of fabrication process. The profile reconstructions are carried out using an appropriate algorithm in the frames of the WKB approximation. The method is applied for few- and single-mode waveguides, obtained by K+-Na+ field assisted ion exchange. The results are corroborated with the reconstruction from the effective refractive indexes measured at a shorter wavelength, as well as with profile study by means of step-by-step etching 相似文献
12.
Sol-gel glass waveguide and grating on silicon 总被引:7,自引:0,他引:7
Najafi S.I. Touam T. Sara R. Andrews M.P. Fardad M.A. 《Lightwave Technology, Journal of》1998,16(9):1640-1646
This paper reports on the fabrication and characterization of hybrid organic-inorganic glass sol-gel slab and channel waveguides by ultraviolet light imprinting in thin films deposited by a one-step dip-coating process. The adjustment of chemical composition of the materials provides precise selection of refractive index from 1.48 to 1.52 at the wavelength of 632.8 mn. The refractive index of the waveguides at 1.55 μm is similar to that of optical fiber, thus reducing the reflection loss between the two to less than 0.01 dB. The effect of ultraviolet light exposure and heat treatment on waveguide refractive index is studied. Fabrication parameters to produce ridge waveguides are optimized to achieve very smooth side walls. Propagation losses in these waveguides are ~0.1 dB/cm. Single mode buried waveguides, at 1.55 μm wavelength, with circular mode profile are demonstrated 相似文献
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A new method for an accurate characterization of the ordinary refractive index profile of proton-exchanged waveguides is presented and discussed. The method is based on the measurement of the power coupled into radiation modes of the waveguide as a function of the corresponding effective indexes, and allows the determination of the depth and of the film refractive index of the ordinary profile by a least squares fitting of the experimental points. The depth and the film refractive index have been experimentally obtained with an accuracy of 0.005 μm and 0.0001, respectively 相似文献
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16.
《Microwave Theory and Techniques》1987,35(6):587-591
Analytical and numerical results for the guided mode characteristics of metal-clad planar waveguides produced by diffusion are developed. Values of the complex propagation constants are obtained numerically and are shown to be in good agreement with the analytical results. These give insight into how waveguide and material parameters determine the loss. Since the profile of the waveguide represents the variation of the refractive index of the diffused-channel waveguide with the depth dimension, the results obtained can be used to reduce the dimensionality of the diffused-channel waveguide and facilitate the application of the effective-index method. 相似文献
17.
本文采用质子交换法制备了Z切LiTaO3晶体平板光波导,并研究了退火前后波导的光学性能。讨论并用实验结果验证了退火前后波导内折射率的分布,实验证明退火前波导层的折射率分布为阶跃型,退火后其分布为费米型。在632.8nm的He-Ne激光波长下的测量结果表明:质子交换LiTAO3波导层折射率增量退火前约为0.012,退火后为0.025。 相似文献
18.
Design of optical circuit devices based on topology optimization 总被引:1,自引:0,他引:1
Y. Tsuji K. Hirayama T. Nomura K. Sato S. Nishiwaki 《Photonics Technology Letters, IEEE》2006,18(7):850-852
We apply a design method based on topology optimization technique to optical waveguide devices. In our approach, after a refractive index profile in a design region is automatically generated using a topology optimization method, the obtained structure is redefined using primitive geometries with some design parameters and those parameters are optimized by a sequential linear programming. As numerical examples, we demonstrate how the method can be used for 90/spl deg/ bends and T-branching waveguides with arbitrary splitting ratio. 相似文献
19.
A domain integral equation approach to computing both the propagation constants and the corresponding electromagnetic field distributions of guided waves in an integrated optical waveguide is discussed. The waveguide is embedded in a stratified medium. The refractive index of the waveguide may be graded, but the refractive indices of the layers of the stratified medium are assumed to be piecewise homogeneous. The waveguide is regarded as a perturbation of its embedding, so the electric field strength can be expressed in terms of domain integral representation. The kernel of this integral consists of a dyadic Green's function, which is constructed using an operator approach. By investigating the electric field strength within the waveguide, it is possible to derive an integral equation that represents an eigenvalue problem that is solved numerically by applying the method of moments. The application of the domain integral equation approach in combination with a numerically stable evaluation of the Green's kernel functions provides a new and valuable tool for the characterization of integrated optical waveguides embedded in stratified media. Numerical results for various channel and ridge waveguides are presented and are compared with those of other methods where possible 相似文献
20.
K. Geary Seong-Ku Kim Byoung-Joon Seo Yu-Chueh Hung Wei Yuan H.R. Fetterman 《Photonics Technology Letters, IEEE》2006,18(1):64-66
Photobleached refractive index tapers in electrooptic polymer rib waveguides, which act as two-dimensional optical mode transformers, are investigated. One taper method involves a discrete step mask-shifting scheme with a fixed intensity UV light source. A second method utilizes a gray-scale mask to precisely control the intensity of UV light reaching each portion of the taper. Using a gray-scale mask, adiabatic refractive index tapers can be inscribed into electrooptic polymer waveguides in a single fabrication step with no scanning parts. Optimized taper profiles are derived and applications for their incorporation into passive-to-active waveguide transitions are described. 相似文献