相位误差对AWG波分复用器非相邻通道串扰影响的分析

分析了工艺制作过程中引入的阵列波导相位误差以及由其所引起的非相邻通道间串扰性能的劣化,给出了相应的分析公式.利用该公式,可以简捷地分析所设计的AWG型器件的非相邻通道串扰水平,为优化AWG型器件的设计提供依据.     

40通道100G间隔AWG的研制

本文利用BPM算法设计了40通道100G间隔的AWG,并利用PLC标准工艺制作了AWG器件.该器件的插入损耗为4 dB,相邻通道串扰为30 dB,非相邻通道串扰为38 dB,1 dB带宽为0.26 nm,实现了预先设计的目标.     

50/100GHz AWG型光学梳状滤波器的设计与制备

以Si基SiO2平面光波导为基础,设计并制备了50/100GHz AWG型光学梳状滤波器.制备得到的AWG型光学梳状滤波器可以覆盖1520～1585nm的波长范围,共有160个信道.功率输出不均匀度＜0.5dB,插入损耗＜8dB,相邻通道的串扰＞13dB,在距离中心频率最远的信道,输出频率偏离ITU标准15GHz.分析了影响器件串扰和信道频率偏移的原因,并提出了相应的解决办法.     

SOI阵列波导光栅的设计与制作

本文讲述了基于SOI材料的5×5阵列波导光栅(AWG)的设计与器件的制作.设计结果显示,通过选择合适的波导结构可以有效地减小器件的偏振特性;采用合适的弯曲半径,不但可以减小器件的损耗,而且可以降低器件的串扰.器件的测试结果表明,器件的中心波长、通道间隔与设计值基本相符;器件的相邻信导串扰接近10dB.器件初步达到分波的功能.     

50/100GHz AWG型光学梳状滤波器的设计与制备

以Si基SiO2平面光波导为基础,设计并制备了50/100GHz AWG型光学梳状滤波器．制备得到的AWG型光学梳状滤波器可以覆盖1520～1585nm的波长范围,共有160个信道．功率输出不均匀度＜0.5dB,插入损耗＜8dB,相邻通道的串扰＞13dB,在距离中心频率最远的信道,输出频率偏离ITU标准15GHz．分析了影响器件串扰和信道频率偏移的原因,并提出了相应的解决办法．     

1×32硅基二氧化硅阵列波导光栅的研制

采用高精度光刻版、PECVD材料生长、反应离子刻蚀和端面8. 角抛光等技术,设计并研制了1×32硅基二氧化硅阵列波导光栅. 研制的AWG芯片,其相邻通道引起的通道串扰小于-28dB,非相邻通道引入的串扰小于-35dB. 通道的插入损耗在进行光纤耦合封装后进一步提高,平均损耗约为4.9dB,不均匀性约为1.72dB.     

1×32硅基二氧化硅阵列波导光栅的研制

采用高精度光刻版、PECVD材料生长、反应离子刻蚀和端面8°角抛光等技术,设计并研制了1×32硅基二氧化硅阵列波导光栅.研制的AWG芯片,其相邻通道引起的通道串扰小于-28dB,非相邻通道引入的串扰小于-35dB.通道的插入损耗在进行光纤耦合封装后进一步提高,平均损耗约为4.9dB,不均匀性约为1.72dB.     

硅基二氧化硅阵列波导光栅相位误差数值分析

采用传输函数法对硅基二氧化硅阵列波导光栅(AWG)的相位系统误差和随机误差进行了详细的分析.系统误差的模拟结果表明阵列波导的有效折射率和相邻阵列波导长度差ΔL的偏移将会对使中心波长λ0偏离设计值,平板波导有效折射率、阵列波导的间距、罗兰圆聚焦长度R的偏移会使通道间隔偏离设计值.随机误差的模拟结果表明相邻阵列波导长度差、阵列波导中芯区折射率、芯区宽度、芯区厚度的随机波动对AWG的串扰影响较大,而波导上、下包层折射率的波动对AWG串扰影响较小.     

硅基二氧化硅阵列波导光栅相位误差数值分析

采用传输函数法对硅基二氧化硅阵列波导光栅(AWG)的相位系统误差和随机误差进行了详细的分析.系统误差的模拟结果表明阵列波导的有效折射率和相邻阵列波导长度差ΔL的偏移将会对使中心波长λ0偏离设计值,平板波导有效折射率、阵列波导的间距、罗兰圆聚焦长度R的偏移会使通道间隔偏离设计值.随机误差的模拟结果表明相邻阵列波导长度差、阵列波导中芯区折射率、芯区宽度、芯区厚度的随机波动对AWG的串扰影响较大,而波导上、下包层折射率的波动对AWG串扰影响较小.     

硅基二氧化硅阵列波导光栅相位误差数值分析

采用传输函数法对硅基二氧化硅阵列波导光栅(AWG)的相位系统误差和随机误差进行了详细的分析. 系统误差的模拟结果表明阵列波导的有效折射率和相邻阵列波导长度差ΔL的偏移将会对使中心波长λ0偏离设计值，平板波导有效折射率、阵列波导的间距、罗兰圆聚焦长度R的偏移会使通道间隔偏离设计值. 随机误差的模拟结果表明相邻阵列波导长度差、阵列波导中芯区折射率、芯区宽度、芯区厚度的随机波动对AWG的串扰影响较大，而波导上、下包层折射率的波动对AWG串扰影响较小.     

Configuration of more than N DWDM channels with only one N × N cyclic-AWG-based wavelength routing device

A wavelength routing device based on only one N × N cyclic arrayed waveguide grating (AWG) having easy extended channels configuration is presented in this paper. It is easy to extend the dense wavelength division multiplexing (DWDM) channel configuration through this wavelength routing device. According to the cyclic wavelength of AWG, the wavelength routing devices are easy to configure more than N extended DWDM channels through cascading more proper tunable fiber Bragg gratings (FBGs). With only one 8 × 8 AWG, two different wavelength routing structures were built to evaluate static crosstalk and the bit-error-rate (BER). Three of the 16 inputted DWDM channels were demonstrated to verify that the proposed wavelength routing device, with only one 8 × 8 AWG, could configure extended DWDM channels without interfering with other channels. The results show that the wavelength routing device can produces a better performance and offers a cheaper way to extend the DWDM channel configuration for a dynamic network.     

An Analytic Approach to Random Phase Error and Its Impact on the Performance and Design of Arrayed-Waveguide Gratings

Random phase error due to fabrication process causes the filter response of arrayed-waveguide grating (AWG) to degrade, especially in terms of crosstalk. In the side-lobe region, which is critical to the channel crosstalk performance, each instantiation of the random phase error can yield a significantly different filter transmission than that of the average for that level of phase error. In this report, the statistical behavior of the AWG filter transmission in the side-lobe region is studied analytically. Both the distribution of random side-lobe level at a given wavelength and an upper bound of the outage probability for side-lobe maxima are given in a simple closed form. Accordingly, a crosstalk margin needs to be allocated to ensure a given fabrication yield and this is shown to depend on the fractional bandwidth of the AWG filter. For filter shapes that are close to Gaussian, this crosstalk margin can be 8 dB or more above the average crosstalk level, for small fractional bandwidth of about 1% and fabrication yields of 80% or higher. These relations should be useful to AWG designers particularly when the underlying fabrication process is susceptible to nonnegligible random phase errors.     

一种降低列阵波导光栅相邻信道串扰的方法

阵列波导光栅 (AWG)作为波长滤波器在光通信领域具有很大的应用前景。串扰是影响阵列波导光栅应用的重要因素之一。为了降低阵列波导光栅相邻信道的串扰 ,本文提出并研究了一种降低阵列波导光栅的新方法。该方法利用阵列波导光栅的衍射特点性 ,通过调节阵列波导光栅的自由光谱范围 (FSR)、罗兰圆焦距和阵列波导数目 ,使得各信道信号的输出极小值处于其它信道输出波导中心 ,无次极大处于其它波导中 ,从而降低了阵列波导光栅的串扰 ,特别是相邻信道之间的串扰。通过光束传播方法 (BPM)的模拟了具有不同FSR的 1× 16阵列波导光栅 ,结果显示 ,该方法能将相邻信道之间的串扰降低约 5 .7dB。     

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     

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。     

阵列波导光栅插入损耗的降低

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,插入损耗是它的一个重要性能指标。本文介绍了多种减小AWG插入损耗的方法,并在此基础上,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。     

Efficient Transmission Scheme for AWG-Based DWDM Millimeter-Wave Fiber-Radio Systems

We propose and demonstrate an upstream transmission scheme using a semiconductor optical amplifier (SOA) for arrayed waveguide grating (AWG)-based dense wavelength-division-multiplexed (DWDM) millimeter-wave fiber-radio systems and show improved link performance. In our scheme, unused optical carriers from the cyclic AWG in the downlink (DL) are tapped for uplink (UL) transmission. An SOA in conjunction with the AWG simultaneously amplifies the DL RF subcarriers and UL optical carrier, thus improving carrier-to-sideband ratio in the DL while also yielding an improved power budget for the UL. Our experimental results show that the proposed scheme can be a practical solution for future bidirectional wavelength interleaved DWDM transmission systems     

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     

消光比在串扰分析中的影响

导出了单一串扰情况下 ,串扰光和系统光噪声共同存在时 ,接收机输入光信号及其基带输出信号的表达式。阐述了信号光与串扰光的物理相干性与信号数字逻辑相关性问题。计算了在最优判决门限情况下 ,背景误码率在10 - 9条件时 ,信号光消光比与串扰光消光比对系统误码率的影响。结果表明 ,消光比在 8～ 12dB的范围内 ,系统的误码特性接近最优。     

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.