阵列波导光栅的研究进展

综述了阵列波导光栅的研究进展,分析了其多功能和多应用的特性,展示了它在未来波分复用通信网中巨大的应用前景。     

阵列波导光栅技术及其研究进展(本期优秀论文)

分析了AWG器件的基本原理,并介绍了近年来人们在研制小尺寸AWG、增加器件信道数量,改善器件的损耗、串扰、偏振敏感性和温度相关性等性能,以及AWG与其他器件集成等方面的最新研究进展.     

Temperature insensitive arrayed waveguide gratings on InPsubstrates

A temperature insensitive arrayed waveguide grating (TI-AWG) with an InGaAsP-InP material system is proposed. Less than 0.1 Å/°C temperature dependence for all eight channels was achieved for the first time even though we used the InGaAsP-InP material system. This novel characteristic is in good agreement with the design principle of the TI-AWG     

Wavelength-tolerant optical access architectures featuringN-dimensional addressing and cascaded arrayed waveguide gratings

This paper describes two- and three-stage wavelength routed optical access networks, which offer wavelength tolerance by using coarse passband-flattened arrayed waveguide grating routers. An N-dimensional addressing strategy enables 6912 customers to be bidirectionally accessed with multi-Gb/s data using only 24 wavelengths and 1.6 nm spacing. These architectures are designed to map onto standard access network topologies, allowing elegant upgradability from legacy passive optical network (PON) infrastructures at low cost     

Simple method to adjust polarization dependence in polymeric arrayed waveguide gratings

Polarization-dependent wavelength shift of a birefringent-polymeric arrayed waveguide grating (AWG) is found to be adjusted simply by controlling the thickness of the first upper cladding layer while forming the upper cladding by several sublayers. Polarization-dependent wavelength shift is reduced to 0.08 from 4.24 nm in a birefringent-polymeric 16 /spl times/ 16 channel AWG on a silicon substrate by this method.     

Low-loss flat-top passband arrayed waveguide gratings realised byfirst-order mode assistance method

A novel method of flattening the passband of an arrayed waveguide grating with a small excess loss is described, which employs a new concept that uses the assistance of the weak first-order mode. A 16-channel 100 GHz-spacing demultiplexer with a fibre-to-fibre loss of less than 3.6 dB and a flattened excess loss of 1.85 dB is demonstrated. The 1 dB down passband is widened 2.2 times     

一种减小聚合物阵列波导光栅光谱漂移的有效方法

报道了一种在工艺制作过程中减小聚合物阵列波导光栅(AWG)器件光谱漂移的有效方法,通过调整波导芯层的旋涂转速来控制芯层的厚度进而可以有效地减小器件的光谱漂移.AWG器件的设计中心波长为1550.918 nm,制作的AWG器件的实际中心波长为1550.85 nm,即利用该方法使传输光谱的漂移减小到0.07nm,远远小于波长间隔0.8 nm,改善了器件的解复用功能.     

AWG插入损耗性能的分析和改善

阵列波导光栅(AWG)是实现密集波分复用(DWDM)光网络的理想器件，插入损耗是它的一个重要性能指标．文章在综述了多种减小AWG器件插入损耗方法的基础上，分析了如何使用楔形波导结构来降低模式失配所导致的耦合损耗．这种方法可以在不增加器件制作难度的同时大大降低AWG的插入损耗，并且适用于各种材料和结构的AWG器件设计。     

New design for low-loss star couplers and arrayed waveguide gratingdevices

We propose a new loss reduction method in star couplers employing UV-written tapers that replace the free propagation region in the conventional star couplers and apply them to an arrayed waveguide grating (AWG) device. The insertion loss of the new AWG device can be reduced to 0.31 dB, which is about 0.7 dB lower than that of the AWG without UV-written tapered waveguides     

Control of higher order leaky modes in deep-ridge waveguides and application to low-crosstalk arrayed waveguide gratings

In a lightwave circuit using a strongly confined waveguide, higher order leaky modes must be suppressed to obtain ideal characteristics, especially in arrayed waveguide gratings (AWGs). Propagation loss for higher order leaky modes in InP-based deep-ridge waveguides was investigated by simulation and experiment. A highly sensitive loss measurement method based on optical low-coherence reflectometry was used to determine the loss, and the relationship between the loss for the higher order mode and AWG crosstalk was investigated. Optimizing the deep-ridge waveguide parameters, especially the core thickness, the refractive index of the core, and the etch depth under the core, significantly reduced the propagation loss for the higher order leaky mode. The effective elimination of the higher order modes will enable fabrication of low-crosstalk AWG routers.     

Reflective arrayed waveguide grating multiplexer

A high-performance reflective arrayed waveguide grating multiplexer/demultiplexer designed for compatibility with silicon integrated circuit processing is described. The grating, folded by a flat reflecting surface, can be printed in a single-exposure field of a photolithographic stepper. Advanced plasma assisted deposition is used to prepare waveguides with very low loss and minimum birefringence. Multiplexers with 40 channels separated by 100 GHz show intrinsic insertion losses of -2.4 dB, channel uniformity less than 0.6 dB, and very low polarization dependent wavelength shift of 0.012 nm.     

Aberration theory of arrayed waveguide grating

The general aberration theory of arrayed waveguide grating (AWG) is proposed in this paper. The derived conclusions can be applied to any symmetrical AWGs. With the aberration theory, the spectral response can be optimized. Some performances of an AWG, for example, crosstalk and channel number, are expected to be improved by reducing the aberrations. A common AWG with the Rowland geometry has low aberrations for the absence of the second-order aberration. To further reduce the aberrations, nonstandard AWGs are considered. The AWG based on three stigmatic points is proved to have a perfect performance     

Silica-based 71-channel arrayed waveguide grating

With the rapid increase of global information capaci-ty,all optical wavelength division multiplexing(WDM)networks are very attractive because they are capable ofprocessing broadband optical signals without convertingthem to electronic signals.Large channe…     

阵列波导光栅复用器优化设计的数值计算

阵列波导光栅(AWG)复用／解复用器的优化设计计算是集成光波导器件设计计算中的难点．文章应用AWG光信号传输特性和光栅方程，提出了AWG组成部分输入／输出波导、阵列波导、平板波导相关参数及阵列波导结构优化设计的数值计算方法，给出了具体的计算数值；该计算方法解决了AWG复用器优化设计计算的问题，为进一步建立AWG的计算机辅助设计提供了基础．     

Athermalisation of silica arrayed waveguide grating multiplexers

Successful athermalisation of a silica arrayed waveguide grating (AWG) multiplexer using compensating longitudinal strain is reported. Peak wavelength shift of <0.04 nm is recorded over 5-70/spl deg/C in a 40/spl times/100 GHz device, representing a 95% reduction on standard silica AWGs, without introduction of birefringence or compromise of optical crosstalk.     

32信道聚合物阵列波导光栅的制作与测试

对一个32通道的聚合物阵列波导光栅进行了研究和制作.经过旋涂、光刻、反应离子刻蚀等工艺过程,利用A1掩膜技术和回融技术进行了器件的制作.实验结果表明,回融技术使样本的波导表面的均方根粗糙度降低了约0.02μm.测试结果表明,器件的结构指标与理论设计值基本相符,并且波导在C波段上实现了单模传输.器件的插入损耗约为35dB,相邻通道串扰小于-20dB,很好地实现了波分复用功能.     

Crosstalk reduction in N×N WDM multi/demultiplexers bycascading small arrayed waveguide gratings (AWG's)

This paper shows a new scheme which improves the crosstalk performance of large optical multi/demultiplexers, a key component in wavelength division multiplexing (WDM) systems. This scheme uses arrayed waveguide gratings (AWG's) of various sizes and requires no additional equipment. It is well known that a large multi/demultiplexer can be constructed by cascading small multi/demultiplexers. We have studied the impact of the number and size of AWG stages on crosstalk performance. This paper proves that to obtain a multistage multi/demultiplexer with minimum crosstalk, the total channel number of each AWG stage must be minimized. For example, cascading 10-channel AWG's and 11-channel AWG's improves the crosstalk performance of a 110-channel multi/demultiplexer by about 7.5 dB. Furthermore, the crosstalk performance degradation due to fabrication error is theoretically investigated taking channel bandwidth into account. Optimum design parameters of multistage AWG's are introduced: When the AWG suppression ratio is 30 dB and the ratio of channel bandwidth to channel spacing is about 0.24, the degradation in crosstalk performance due to fabrication error is minimized. The tradeoff between the crosstalk performance and the efficiency in terms of hardware and wavelength are also discussed. It is discovered that this simple scheme can yield a crosstalk-free WDM router. Crosstalk reduction obtained by this scheme allows the realization of flexible multiwavelength networks based on wavelength routing     

Low chromatic-dispersion flat-top arrayed waveguide grating filter

A low chromatic dispersion (CD) flat-top arrayed waveguide grating (AWG) filter with a novel parabolic waveguide horn is proposed, and a 100 GHz-spacing 16-channel flat-top AWG that reduces the CD from -20.9 to -3.2 ps/nm has been successfully fabricated.     

An asymmetric discrete-time approach for the design and analysis ofperiodic waveguide gratings

A discrete-time approach is introduced for the analysis of periodic waveguide gratings with gain (or loss) extending concepts developed for transfer matrix and Gel'fand-Levitan-Marchenko (GLM) inverse scattering techniques. The periodic waveguide grating with gain (or loss) is modeled as a lossy layered dielectric that allows for a digital signal processing (DSP) formulation of the forward and inverse scattering problem. It is shown that the DSP forward scattering formulation as an asymmetric two-component wave system is equivalent to the impedance matching matrix method. A numerical example is presented to emphasize this result. The DSP formulation is an exact discrete design, not just an approximation to a continuous design, and includes all multiple reflections, transmission scattering losses, and absorption effects. A comparison of the continuous GLM, discrete GLM, and discrete Krein inverse problem formulations for a medium with gain (or loss) is presented. The discrete lossy formulations generalize previous lossless results and are found from two different types of reflection data. Since slab gratings are discrete (not continuous) structures, the integral equations used to describe the continuous inverse problem are shown to become matrix equations. Thus, our result enables fast algorithms to be used to solve the inverse problem. A fast algorithm is presented allowing for the complete reconstruction of the grating parameters from its two-sided response in a recursive (slab by slab) fashion     

Si纳米线阵列波导光栅制备

采用绝缘层上Si(SOI)材料设计制备了3×5纳米线阵列波导光栅(AWG),器件大小为110μm×100μm。利用简单传输法模拟了器件的传输谱,并采用二维时域有限差分(FDTD)模拟中心通道输出光场的稳态分布,模拟结果表明,器件的通道间隔为11 nm,通道间的串扰为18 dB。通过电子束曝光(EBL)和感应耦合等离子(ICP)刻蚀制备了所设计的器件,光输出谱测试分析表明,器件中心通道的片上损耗为9 dB,通道间隔为8.36～10.40 nm,中心输出通道的串扰为6 dB。在误差允许范围内,设计和测试的结果一致。