Filling the frequency gaps of a planar optical spectrum analyzer using a 2.5-GHz-spaced arrayed-waveguide grating in the C and L bands

A vernier configuration in a 2.5-GHz-spaced 128-channel arrayed-waveguide grating (AWG) for use as a secondary demultiplexer in a planar optical spectrum analyzer was incorporated with a tandem configuration. The frequency changes were 3.0 and 2.5 GHz for adjacent input and output ports, respectively. By selecting any of the eight input ports of the AWG, new passbands could be generated in the gaps between adjacent passbands and in the gaps produced when the diffraction order of the AWG was changed. Enough new passbands were generated to achieve frequency sampling at 1-GHz intervals without dead frequency points in the C and L bands of optical fiber amplifiers.     

The AWG/spl par/PSC network:a performance-enhanced single-hop WDM network with heterogeneous protection

Single-hop wavelength-division-multiplexing (WDM) networks based on a central passive star coupler (PSC) or arrayed-waveguide grating (AWG) hub have received a great deal of attention as promising solutions for the quickly increasing traffic in metropolitan and local area networks. These single-hop networks suffer from a single point of failure: if the central hub fails, then all network connectivity is lost. To address this single point of failure in an efficient manner, we propose a novel single-hop WDM network, the AWG/spl par/PSC network. The AWG/spl par/PSC network consists of an AWG in parallel with a PSC. The AWG and PSC provide heterogeneous protection for each other; the AWG/spl par/PSC network remains functional when either the AWG or the PSC fails. If both AWG and PSC are functional, the AWG/spl par/PSC network uniquely combines the respective strengths of the two devices. By means of analysis and verifying simulations we find that the throughput of the AWG/spl par/PSC network is significantly larger than the total throughput obtained by combining the throughput of a stand-alone AWG network with the throughput of a stand-alone PSC network. We also find that the AWG/spl par/PSC network gives over a wide operating range a better throughput-delay performance than a network consisting of either two load sharing PSCs in parallel or two load sharing AWGs in parallel.     

Measurement of slowly varying component in phase error distribution of a large-channel-spacing arrayed-waveguide grating

It has been difficult to measure the phase error distribution of a large-channel-spacing arrayed-waveguide grating (AWG) with optical low coherence interferometry (OLCI). In this reported work OLCI was successfully used to measure the slowly varying component in the distribution of a 1 THz-spaced AWG that was the primary filter in an ultra-high-density multi/demultiplexer. The spectral sidelobe of the AWG can be reduced by using the component to achieve the lowest possible accumulated crosstalk in the multi/demultiplexer.     

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.     

The FT/sup /spl Lambda//-FR/sup /spl Lambda// AWG network: a practical single-hop metro WDM network for efficient uni- and multicasting

Single-hop wavelength-division-multiplexed (WDM) networks with a central passive star coupler (PSC), as well as single-hop networks with a central arrayed-waveguide grating (AWG) and a single transceiver at each node, have been extensively studied as solutions for the quickly increasing amounts of unicast and multicast traffic in the metropolitan area. The main bottlenecks of these networks are the lack of spatial wavelength reuse in the studied PSC-based networks and the single transceiver in the studied AWG-based metro WDM networks. This paper describes the development and evaluation of the FT/sup /spl Lambda//-FR/sup /spl Lambda// AWG network, which is based on a central AWG and has arrays of fixed-tuned transmitters and receivers at each node. Transceiver arrays are a mature technology, making the proposed network practical. In addition, the transmitter arrays allow for high-speed signaling over the AWG while the receiver arrays relieve the receiver bottleneck arising from multicasting in conjunction with spatial wavelength reuse on the AWG. The results from probabilistic analysis and simulation reported here indicate that the FT/sup /spl Lambda//-FR/sup /spl Lambda// AWG network gives particularly good throughput-delay performance for a mix of unicast and multicast traffic.     

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．     

基于SOI的16通道200GHz阵列波导光栅

设计并制作了基于绝缘体上硅(SOI)材料的1×16阵列波导光栅(AWG).该AWG器件的中心波长为1 550 nm,信道间隔为200 GHz,采用了脊型波导结构.首先确定了波导的结构尺寸以保证单模传输,并利用束传播法(BPM)模拟了波导间隔、弯曲半径和锥形波导长度等参数对器件性能的影响,对器件结构进行了优化,同时也利用BPM方法模拟了器件的传输谱.模拟结果显示:器件的最小信道损耗为4.64 dB,串扰小于-30 dB.根据优化的器件结构,通过光刻等半导体工艺制作了AWG,经测试得到AWG器件的损耗为4.52～8.1 dB,串扰为17～20 dB,能够实现良好的波分复用/解复用功能.     

全聚合物型无热化阵列波导光栅参数的优化

研究一种新型无热化阵列波导光栅,这是由聚合物组成的一种新型阵列波导光栅。阵列波导光栅对温度的依赖性受波导物质的折射率、热膨胀系数和波导芯的尺寸影响,所以,通过调节这些参数就可以减小温度对阵列波导光栅的影响。优化得到全聚合物型阵列波导光栅在温度20℃～70℃范围内波谱漂移小于常规型AWG结构的0.5%。     

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     

A Novel Memory Compress Algorithm for Arbitrary Waveform Generator

A memory compress algorithm for 12-bit Arbitrary Waveform Generator (AWG) is presented and optimized. It can compress waveform memory for a sinusoid to 16× 13hits with a Spurious-Free Dynamic Range (SFDR) 90.7dBc (1/1890 of uncompressed memory at the same SFDR) and to 8× 12bits with a SFDR 79dBc. Its hardware cost is six adders and two multipliers. Exploiting this memory compress technique makes it possible to build a high performance AWG on a chip.     

Reducing the thermal dependence of silica-based arrayed-waveguide grating using inorganic-organic hybrid materials

This study demonstrates the application of a temperature-independent arrayed-waveguide grating (AWG) using a simple hybrid waveguide structure composed of silica core/inorganic-organic hybrid material overcladding layer. The thermooptic effect of the hybrid materials varies over a wide range of temperature and provides athermal characteristics in an AWG. The temperature dependence of the AWG was reduced through the precision control of the thermooptic coefficient of the hybrid materials (/spl Delta//spl lambda/=/spl sim/3pm//spl deg/C).     

Multistage WDM access architecture employing cascaded AWGs

Here we propose passive/active arrayed waveguide gratings (AWGs) with enhanced performance for system applications mainly in novel access architectures employing cascaded AWG technology. Two technologies were considered to achieve space wavelength switching in these networks. Firstly, a passive AWG with semiconductor optical amplifiers array, and secondly, an active AWG. Active AWG is an AWG with an array of phase modulators on its arrayed-waveguides section, where a programmable linear phase-profile or a phase hologram is applied across the arrayed-waveguide section. This results in a wavelength shift at the output section of the AWG. These architectures can address up to 6912 customers employing only 24 wavelengths, coarsely separated by 1.6 nm. Simulation results obtained here demonstrate that cascaded AWGs access architectures have a great potential in future local area networks. Furthermore, they indicate for the first time that active AWGs architectures are more efficient in routing signals to the destination optical network units than passive AWG architectures.     

Interrogation of a Long-Period Grating Sensor by a Thermally Tunable Arrayed Waveguide Grating

An interrogation technique for a long-period grating (LPG) sensor is studied theoretically and experimentally. By employing a thermally tunable arrayed waveguide grating (AWG), the center wavelength of the LPG sensor is successfully measured using the linear temperature dependence of the AWG transmission wavelengths. Initial results show that the proposed interrogation technique can provide a resolution of 1 pm and interrogation range of 25 nm. Furthermore, this technique has the potential of being packaged into a low-cost and compact-size device.      

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     

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.     

Second- and third-order dispersion compensator using ahigh-resolution arrayed-waveguide grating

We have proposed a dispersion compensation scheme that uses a high-resolution arrayed-waveguide grating (AWG). When the diffraction order of the AWG is 59 and the number of waveguides in an arrayed-waveguide is 340, the calculated maximum second- and third-order dispersion compensation range is 18.0 ps/nm and ±6.0 ps/nm² , and 1100 ps/nm and ±937.5 ps/nm², for a 1 ps-pulse and a 12.5 ps-pulse, respectively. In experiments, second-order dispersion (-0.8 to +5.2 ps/nm) is effectively compensated for 1,1-ps pulses; and. Pulse compression by third-order dispersion compensation is successfully demonstrated     

Design and fabrication of 25-channel 200 GHz AWG based on Si nanowire waveguides

A 25-channel 200 GHz arrayed waveguide grating (AWG) based on Si nanowire waveguides is designed, simulated and fabricated. Transfer function method is used in the simulation and error analysis of AWG with width fluctuations. The 25-channel 200 GHz AWG exhibits central channel insertion loss of 6.7 dB, crosstalk of ?13 dB, and central wavelength of 1 560.55 nm. The error analysis can explain the experimental results of 25-channel 200 GHz AWG well. By using deep ultraviolet lithography (DUV) and inductively coupled plasma etching (ICP) technologies, the devices are fabricated on silicon-on-insulator (SOI) substrate. This work has been supported by the National Key Research and Development Program of China (No.2016YFB0402504), and the National Natural Science Foundation of China (Nos.61435013 and 61405188). E-mail:zhangjiashun@semi.ac.cn      

适用于阵列波导光栅制作的厚SiO_2陡直刻蚀技术

采用ICP- 98型高密度等离子体刻蚀机进行了厚Si O2 陡直刻蚀技术的研究,利用双层掩膜技术解决了“微掩膜现象”问题,刻蚀获得12 .4 μm的陡直Si O2 光波导剖面,并将这一刻蚀技术用于阵列波导光栅的制作中.     

Athermalized Polymeric Arrayed‐Waveguide Grating by Partial Detachment from a Si Substrate

We demonstrate a new fabrication method for adjusting the temperature dependence of a polymeric arrayed‐waveguide grating (AWG) on a Si substrate. A temperature‐dependent wavelength shift of ?0.1 nm/°C in a polymeric AWG on a Si substrate is reduced to +0.01 nm/°C by detaching part of the polymer film, including the grating channel region of the AWG, from the Si substrate while the other parts remain fixed on the substrate.     

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.