Analysis and design of integrated optical mirrors in planar waveguide technology

We demonstrate integrated optical mirrors in alumina-based waveguides on oxidized silicon substrates. The finite-element method (FEM) is employed for the design of mirrors operating between 1.31 and 1.55 /spl mu/m at both fundamental polarizations. Excellent agreement between measurement and simulation is achieved for the dispersion behavior of the device. The highly polarization-dependent scattering loss at the reflecting interface is well predicted considering approximate values for the reactive ion etching (RIE) process induced surface roughness.     

A polymer optical waveguide with out-of-plane branching mirrors forsurface-normal optical interconnections

We have developed a simultaneous fabrication method using temperature control reactive ion etching (RIE) for channel optical waveguides incorporating plural out-of-plane branching mirrors made from polymer film. By using this method, the etching rate can be adjusted locally by controlling the temperature. This technology also enables the formation of trenches of various depths on the same polymer optical waveguide. We noted from scanning electron microscope (SEM) observations that simultaneous control of the mirror tilt angle and a smooth core surface could be achieved. To be specific, a heat treatment temperature of 130-135°C appears to be the optimum to maintain a rectangular cross section and to achieve a sufficiently smooth core surface for a polymethyl methacrylate (PMMA) waveguide. The measured propagation loss is small, in spite of the presence of a high-Δ waveguide (Δ=5.4%). For example, losses of 0.1, 0.3, and 0.7 dB/cm are measured at wavelengths of 650 nm, 850 nm, and 1.3 μm, respectively. From far-field pattern (FFP) measurements, we found that the mirror plane was almost rectilinear, and that the reflected light can be captured efficiently by a photodiode. In operational temperature tests, we showed that intensity fluctuations of the coupling light can be reduced to less than 1.5 dB for the temperature range between -25°C and +85°C by adopting a sandwich structure with glass plates     

Loss analysis and interference effect in semiconductor integrated waveguide turning mirrors

Semiconductor integrated waveguide turning mirrors (IWTM) are investigated using the beam propagation method. A mirror is fabricated and modeled along with realistic geometries in the presence of offset and roughness of the mirror surface. An interference effect between waves reflected at different surfaces in the device is evidenced, that has strong impact on the device performance in the case of weakly-confining structures. A widely-accepted fabrication approach is criticized in view of this effect. A solution is outlined that minimizes the losses due to either technological limitations or interference.     

芯片级全固化集成光波导陀螺

高灵敏、全固态、集成制造的微光-机-电陀螺是未来发展的新一代惯性器件,在深空探测、载人航天以及飞行器制导技术领域具有迫切应用需求.提出基于光波导微腔透射谱输出特性的惯性测量方法与系统基础结构,并对其惯性测量原理、微加工工艺以及耦合性能进行了讨论.利用数值拟合得到波导耦合系统设计优化参数,采用激光熔融热处理技术,降低了波...     

Analysis of optical waveguide discontinuities

A novel approach for analyzing discontinuity problems in optical waveguides is presented. The method is a combination of the vector-finite-element method and the least-squares boundary residual method. The vector-H-field-finite-element method is capable of providing accurate eigenvalues and eigenvectors for a wide range of optical waveguide problems, including arbitrary shape, arbitrary index distribution, and anisotropic materials. The least-squares boundary residual method matches the continuity of tangential fields in the least-squares sense, taking into account many modes at the discontinuity plane, to give the general scattering matrix. A few results are presented to show the usefulness of the approach     

Si基集成光学陀螺中弯曲波导特性研究

给出了Si基集成光学陀螺的光路结构,理论计算了余弦型弯曲波导的弯曲半径和弯曲损耗。仿真分析了弯曲波导的宽度、长度与弯曲损耗的关系,进而设计了集成光学陀螺用"K"形耦合器,并通过R-soft软件进行了仿真分析。搭建了弯曲波导的实验测试装置,分别测试了弯曲波导的传输损耗与光模场,结果表明,波导单位损耗为0.014dB/cm,验证了理论计算结果的正确性。采用光束扫描法测试了弯曲波导的模场,实验结果与理想高斯拟合曲线吻合。     

Polysiloxane optical waveguide layer integrated in printed circuit board

A hybrid electrical-optical circuit board is demonstrated using polysiloxane as low-loss and high-temperature stable waveguide material system. After board lamination at 180/spl deg/C for two hours and a subsequent annealing at 230/spl deg/C for 5 minutes the waveguide insertion loss is 0.05 dB/cm at 850 nm wavelength.     

集成光波导电场传感器分段电极频率响应分析

为了研究集成光波导电场传感器分段电极的频率响应特性,采用时域有限差分法进行了数值计算,并在吉赫兹横电磁波室中对实际制作器件的频率响应特性进行了测试.结果表明,当分段数固定在10、电极总长度从42mm减小到12mm时,频率响应带宽从2.68GHz增加到5.91GHz;而当电极总长度保持为42mm、分段数从10增加到30时...     

基于SOI的光波导和V形槽集成器件

文章介绍了一种基于SOI的集成半导体器件。设计了5μm×5μm的单模光波导,并用APSS软件进行了光场模式分析;利用KOH各向异性腐蚀制造了直的脊波导、Y分支器和V形槽;最后,利用紫外光敏胶将波导和光纤固定。     

Silicon oxynitride integrated waveguide for on-chip optical interconnects applications

This work explores the microfabrication technology for realizing miniature waveguide structure for on-chip optical interconnects applications. Thick oxynitride films were prepared by plasma enhanced chemical vapor deposition (PECVD) with N₂O, NH₃ and SiH₄ precursors. The composition and the bonding structure of the oxynitride films were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectroscopy. Results showed that the silicon oxynitride deposited with gas flow rates of NH₃/N₂O/SiH₄ = 10/400/10 (sccm) has favorable properties for integrated waveguide applications. The refractive index of this layer is about 1.5 and the layer has comparative low densities of O–H and N–H bonds. The hydrogen bonds can be further eliminated with high temperature annealing of the as-deposited film in nitrogen ambient and the propagation loss can be reduced significantly with thermal annealing. An integrated miniature waveguide with cross-section of 2 μm × 3 μm was realized with the proposed technology. The waveguide is able to transmit signal in either TE or TM mode with propagation loss <0.6 dB/cm (at 1550 nm) and bending radius of about 6 μm.     

Effect of waveguide optical scattering on the integrated optical spectrum analyzer dynamic range

The dynamic range limited by optical scattering in the integrated optical spectrum analyzer is considered. Calculations of dynamic range as a function of waveguide attenuation and surface roughness characteristics are presented. Dynamic range is found to decrease with increasing attenuation, to be nearly independent of the surface roughness correlation length for a fixed attenuation, and to be independent of the Fourier transform lens focal length. Adjacent channel rejection is found to fall off slowly. The effect of lens scattering is shown only to be important for cases in which waveguide scattering is very small and lens scattering is very high.     

Electrical and acoustical crosstalk in integrated optical strip waveguide devices

Observations of electrically and acoustically induced crosstalk in LiNbO3 waveguide phase modulators at ? = 0.633 ?m are reported. In the tested device, crosstalk attenuation was as low as 23 dB at 700 MHz and 29 dB at 22.83 MHz, which is caused by RF electromagnetic field coupling and by acoustical coupling, respectively, Crosstalk measurements are made as a function of frequency in the electrical and optical domain.     

Analysis of a PIN photodiode with integrated waveguide

The absorption coefficient of an InGaAs PIN photodiode integrated with an InGaAsP-InP waveguide is analysed by means of the mode-matching technique. The results compare excellently to published data for ? = 1.3 ?m. It is shown that by an optimised device structure the absorption coefficient can be increased to about 0.15 dB/?m, enabling reduced detector length and smaller capacitance.     

新型的Si基量子线光波导及其对发展集成光学的意义

新型的Si基量子线光波导具有亚波长甚至纳米尺度的光限制能力,还可以实现小曲率半径的低损耗光传输,因此可以实现高密度集成和纳米集成,成为集成光学领域的研究热点.文章简要介绍Si基量子线光波导的结构和原理、独特优势及其在发展高密度密集纳米集成光路上的应用,并预测了应用于未来集成光路中的新型导光波导的发展方向.     

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.     

光学镜面污染颗粒吸收特性的影响分析

针对实际工作中的光学元件表面粒子污染,以米氏理论为基础,分析了在风沙地区空气中污染颗粒(以SiO2为主)对入射激光能量的吸收效应。此外,进一步分析空气洁净度、元件工作面的朝向以及放置时间等对光学元件表面吸收特性的影响。结果表明,空气洁净度等级越高、元件工作面朝上、放置时间越久,光学元件的表面吸收能力越强。研究成果可为实际应用中光学系统的镜面污染控制提供理论参考。     

Resonant nonlinear optical properties of GaAs-GaAlAs singlequantum-well waveguide and an integrated asymmetric Mach-Zehnderinterferometer

The resonant refractive and absorptive optical nonlinearities of a GaAs-AlGaAs single quantum-well waveguide are characterized. The recovery time of the absorptive nonlinearity is measured as 125 ps. All-optical operation of an integrated asymmetric Mach-Zehnder interferometer is demonstrated, using intense ~50-ps pulses from a mode-locked Ti:sapphire laser. The device operation is detrimentally affected by thermally induced changes in the refractive index even in a 50 ps timescale     

Theory of waveguide laser resonators with small curvature mirrors

A theoretical investigation into the eigenmodes of a waveguide resonator with small curvature mirrors is presented. Field differential equations are derived. Eigenfunctions and eigenvalues are given approximately. Cut-off curvatures are obtained. A criterion which can help to distinguish between a waveguide laser resonator and an open Fabry-Perot one is proposed     

Monolithic integrated waveguide photodetector

An InGaAs photodetector for detection in the 1.0?1.5?m wavelength range has been integrated at the end of and above a ridge waveguide in InP. The waveguides were in n?-InP/n+-InP and had an average propagation loss of 3dB/cm at 1.15?m. The reflection losses were 3dB and the coupling loss was 2dB. The photodetector was an InGaAs photoconductor lattice-matched to InP and exhibited a bias-dependent optical gain of up to 2.5 with a unity-gain quantum efficiency of 49% at 1.15?m. 25% of the guided light was absorbed by the photoconductor. The speed of the photoconductor was found to be bias-dependent, varying from 10 ns to 150 ns rise/fall times.