Analysis of Optical Signal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.     

Analysis of Optical Singal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

Based on the electromagnetic field theory,the optical signal transmission characteristics in input/output waveguides,slab waveguides and arrayed waveguides of the arrayed waveguide grating(AWG) multi/demultiplexer are analyzed.The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed.This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.     

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     

阵列波导光栅复用/解复用器研究进展

综述了阵列波导光栅(AWG)复用/解复用器的最新研究进展,并对该种器件的前景进行了展望.     

Analysis and Development of Fixed and Variable Waveband MUX/DEMUX Utilizing AWG Routing Functions

We develop and analyze a new waveband multi/demultiplexer that exploits the routing functions of arrayed-waveguide gratings (AWG). The device can accommodate multiple input/output fibers simultaneously and be implemented monolithically using silica planar lightwave circuit (PLC) technology. We analyze AWG port usage for variants of the proposed multi/demultiplexers. The important characteristic of the device, its coherent and incoherent crosstalk performance is investigated. A technique to reduce the crosstalk is presented. We extend the capability of the device so that the waveband bandwidth can be changed by adding small switches. Experiments confirm the excellent performance of the proposed waveband multi/demultiplexer.      

由5个AWG组成的600个通道的光波分复用器

本文介绍了有 6 0 0个通道、通道间隔为 2 5 GHz的光波分复用器。该波分复用器是由 1个 8通道间隔为 1.875 THz的母阵列波导光栅 (AWG)和 4个 12 8× 12 8的通道间隔为 2 5 GHz的子阵列波导光栅级联而成的。这种设计因为其体积小而在超密集的波分复用器的发展中更富有竞争力     

阵列波导光栅复用/解复用器焦场的分析及光栅孔径对器件串扰影响的数值分析

利用脉冲响应函数方法,分析计算了阵列波导光栅(AWG)中的焦场分布,得到信号串扰值与AWG孔径以及波导间距的关系。方法简便可行,物理意义鲜明。     

Low-crosstalk 10-GHz-spaced 512-channel arrayed-waveguide gratingmulti/demultiplexer fabricated on a 4-in wafer

We report a 10-GHz-spaced 512-channel arrayed-waveguide grating (AWG) multi/demultiplexer fabricated on a 4-in wafer. We achieved this by folding the 7-cm-long slab waveguides of a conventionally configured AWG, so that the whole configuration was contained in the wafer and then attached reflecting mirrors at the folded parts. Phase compensation of the fabricated AWG was performed by means of ultraviolet irradiation through a metal mask     

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．     

Measurement of phase and amplitude error distributions in InP-basedarrayed-waveguide grating multi/demultiplexers

The authors have measured the phase and amplitude error distributions in an InP-based arrayed-waveguide grating (AWG) multi/demultiplexer using Fourier transform spectroscopy and signal data processing. The signal data processing technique was based on wavenumber scale transformation and was applied to reduce the effect of second-order dispersion in a measured interferogram. The results reveal that the main origins of the crosstalk and dispersion in an InP-based AWG are random and slowly-varying phase errors, respectively     

1.5%-/spl Delta/ athermal arrayed-waveguide grating multi/demultiplexer with very low loss groove design

We describe a compact 1.5%-/spl Delta/ athermal silica-based 100-GHz-spacing 16-channel arrayed-waveguide grating (AWG) multi/demultiplexer with a modified groove design for a very low excess loss. We propose new approaches for modifying the shape of the grooves and the arrayed waveguides and optimize the shape modifications for 1.5%-/spl Delta/ waveguides. By employing this modified groove design, we greatly reduced the groove excess loss from 1.9 to 0.4 dB in the 1.5%-/spl Delta/ athermal AWG.     

A.2.5 GHz-spaced 1080-channel tandem multi/demultiplexer coveringthe. S-, C-, and L-bands using an arrayed-waveguide grating withGaussian passbands as a primary filter

We describe a low-loss 25-GHz-spaced multi/demultiplexer with more than 1000 channels that covers the S-, C-, and L-bands of optical fiber amplifiers. It was achieved by cascading a 2.5-THz-spaced arrayed-waveguide grating (AWG) with Gaussian passbands as a primary filter and ten 25-GHz-spaced 1×200 AWGs as secondary filters in a tandem configuration     

Polymeric optical waveguide circuits formed using silicone resin

Polymeric optical waveguides fabricated using a newly developed silicone resin have a low birefringence as well as low propagation loss and good environmental stability. Optical waveguide circuits including a directional coupler, an arrayed waveguide grating (AWG) multi/demultiplexer, and a digital thermooptic (TO) switch are successfully realized using the silicone resin     

Improve Channel Uniformity of an Si-Nanowire AWG Demultiplexer by Using Dual-Tapered Auxiliary Waveguides

Dual-tapered auxiliary waveguides at the exit of the waveguide array are introduced to improve the channel uniformity of an Si-nanowire-based arrayed waveguide grating (AWG) demultiplexer. By using a hybrid simulation method, the dual-tapered auxiliary waveguides of the AWG demultiplexer are optimized reliably and efficiently. A 12-channel AWG demultiplexer is designed as an example, and a small nonuniformity (< 0.5 dB) is achieved.     

基于SOI材料的偏振不敏感的阵列波导光栅

阵列波导光栅(AWG Arrayed Waveguide Grating)是实现多通道密集波分复用(DWDM Dense Wavelength Division Multiplexing)光网络的理想器件,偏振敏感性是它的一个重要性能指标。本文针对SOI材料的阵列波导光栅,分析了如何采用特殊的波导结构来减小它的偏振相关性,并对16通道、间隔为0．8nm的AWG解复用器进行了计算,结果表明其偏振敏感性低于0．06nm。     

Compensation for Second-Order Temperature Dependence in Athermal Arrayed-Waveguide Grating Realizing Wide Temperature Range Operation

We propose a new compensation technique for the second-order temperature dependence in a silica-based arrayed-waveguide grating (AWG) multi/demultiplexer with a resin-filled groove that realizes a wide operating temperature range. We newly employ an additional interferometer in the input port and control the optical field perturbation by using a first-mode lightwave at the entrance to the first slab waveguide. We employ the design to fabricate a 32-channel 100-GHz-spacing athermal AWG that is as compact as a conventional AWG, and demonstrate a reduction in the passband wavelength variation from 70 to 22 pm over an extended $-$ 40 $^{circ}hbox{C}$ to 80 $^{circ}hbox{C}$ temperature range.      

Optimal design of an MMI coupler for broadening the spectral response of an AWG demultiplexer

Optimal design of a multimode interference (MMI) coupler for broadening the spectral response of an arrayed-waveguide grating (AWG) demultiplexer is considered. By using a Gaussian beam approximation, an analytical expression for the spectral response of an AWG demultiplexer (with an MMI section) is obtained. A simple analytical formula is derived to relate the optimal MMI length to the separation between the peaks of the twofold images in the MMI region. This peak separation is related to the width of the MMI section. In the proposed design method, a required 1-dB passband width determines the peak separation, which then determines the optimal value for the length of the MMI section according to the analytical formula. The designed flat-top AWG demultiplexer is verified by the beam propagation method.     

50-GHz-Spacing Athermal Mach–Zehnder Interferometer-Synchronized Arrayed-Waveguide Grating With Improved Temperature Insensitivity

We describe a technique designed to compensate for the residual temperature sensitivity of an athermal silica-based arrayed-waveguide grating (AWG) and its application to a 50-GHz-spacing multi/demultiplexer with a low loss and a wide passband. The device has a Mach–Zehnder interferometer (MZI)-synchronized configuration, in which the AWG and the MZI are athermalized with resin-filled grooves. The point is that we employ a temperature-dependent phase-generating coupler (TD-PGC) in the MZI to compensate for the second-order temperature dependence of the AWG passband wavelength. The fabricated device exhibits practical characteristics including a low loss of less than 3.5 dB and a wide 0.5-dB bandwidth of 24.1 GHz as well as a reduced wavelength variation of less than 10 pm in a ${-}$ 5 $^{circ}hbox{C}$ to 65 $^{circ}hbox{C}$ temperature range.      

Crosstalk reduction in arrayed-waveguide grating multiplexer/demultiplexer using cascade connection

This paper proposes a cascade-connected arrayed-waveguide grating (AWG) as a solution to the problem of crosstalk accumulation in a large-scale AWG multiplexer/demultiplexer (MUX/DEMUX) and demonstrates a 64-channel cascaded AWG module with a very low background crosstalk of less than -80 dB and a total crosstalk of about -34 dB. In this paper, the authors densely integrate 64 additional compactly designed crosstalk-suppressing AWGs whose bandwidths were carefully optimized and directly attach them to a conventional 64-channel AWG. Consequently, in addition to a very low crosstalk, a low insertion loss and a compact size without passband shape distortion are achieved with this module. Based on the performance of the cascaded AWG module, it is then estimated that it is possible to realize a 1000-channel AWG MUX/DEMUX that is free from the problem of crosstalk accumulation.     

An array of photonic filtering advantages:arrayed-waveguide-grating multi/demultiplexers for photonicnetworks

The author introduces the principles, fabrication techniques, and recent progress of planar-type arrayed-waveguide-grating (AWG) multi/demultiplexers, which have been developed for wavelength division multiplexing (WDM)-based photonic networks. The AWG has already been used in point-to-point WDM systems and is a key component in the construction of flexible and large-capacity WDM networks. This is because, compared with conventional filters consisting of thin-film interference filters and micro-optics, the AWG offers the advantages of low loss, high port counts, and mass productivity. Further progress on the AWG is expected to contribute greatly to the construction of future photonic networks including optical add/drop multiplexing systems and optical crossconnect systems