一种基于采样布拉格光栅的梳状滤波器解决方案

基于采样布拉格光纤光栅,设计出一种多通道数梳状滤波器,所设计的梳状滤波器可应用于光纤通信中的波分复用（WDM）系统。在光栅中引入一种非连续线性啁啾阶梯式结构,并且在采样内,使折射率调制深度符合汉明分布,设计出一个具有26个通道、通道间隔25GHz的梳状滤波器,它能够产生具有平顶、陡峭边沿以及高透射率的多个相同的通带,可用作多通道光分插复用器,广泛应用于WDM系统。     

Flat Filter Based on a Chirped Super Moiré Grating

In this paper, super Moiré grating (SMG) with multiple superimposed gratings, in the best of our knowledge, is studied at first time. A flat multichannel transmission filter based on a chirped SMG with three superimposed gratings can be achieved, which benefits wavelength-division multiplexing (WDM) system. At the same time, a reflection filter can also be obtained in a chirped SMG, which can be used as an optical add/drop multiplexer filter for WDM system.     

Dispersive properties of optical filters for WDM systems

Wavelength division multiplexing (WDM) communication systems invariably require good optical filters meeting stringent requirements on their amplitude response, the ideal being a perfectly rectangular filter. To achieve high bandwidth utilization, the phase response of these filters is of equal importance, with the ideal filter having perfectly linear phase and therefore constant time delay and no dispersion. This aspect of optical filters for WDM systems has not received much attention until very recently. It is the objective of this paper to consider the phase response and resulting dispersion of optical filters in general and their impact on WDM system performance. To this end we use general concepts from linear systems, in particular, minimum and nonminimum phase response and the applicability of Hilbert transforms (also known as Kramers-Kronig relations). We analyze three different classes of optical filters, which are currently being used in WDM systems and compare their performance in terms of their phase response. Finally, we consider possible ways of linearizing the phase response without affecting the amplitude response, in an attempt to approximate the ideal filter and achieve the highest bandwidth utilization     

相移布喇格光栅滤波器的分析及其串扰对FDM－FSK光纤传输系统复用路数的影响

提出并分析了一种新型的布喇格光栅滤波器，用模式耦合方程分析了滤波器的传输特性，计算了通带宽度、自由谱宽和精细度。并把它用在以频移键控（ＦＳＫ）方式调制的频分复用系统中，得到了比较理想的结果。     

A wavelength-tunable semiconductor amplifier/filter for add/drop multiplexing in WDM networks

Reconfigurable channel drop in a wavelength-division multiplexed system is demonstrated using a packaged semiconductor amplifier/filter. The filter is electrically tunable over 9.0 nm with a 0.9-nm width and is used with an optical circulator to demultiplex three 5.0-Gb/s WDM channels spaced by 2.25 nm. A receiver sensitivity improvement and low optical crosstalk is observed over a dynamic range of nearly 10 dB.     

Effects of filter concatenation for directly modulated transmissionlasers at 2.5 and 10 Gb/s

We report computer simulation results of the effects on optical signal quality of passage through a cascade of wavelength division multiplexing (WDM) filters-multiplexers and demultiplexers-for directly modulated lasers with different chirp characteristics. In particular, lasers with transient or adiabatic chirp characteristics at 2.5 Gb/s and 10 Gb/s are investigated, and we find clear differences between the laser types with respect to filter concatenation effects. Filters with an optical bandwidth suitable for a 200-GHz channel-spacing system are considered, and we evaluate the system behavior as a function of laser frequency offset for a fixed number of filters. The reference network architecture used for the simulations is an optically transparent metropolitan scale network in which the WDM signals may be demultiplexed and then multiplexed again at multiple optical network elements. The signal quality is evaluated in terms of a distortion-induced eye-closure penalty as well as the excess attenuation or loss suffered. We find that transient chirp-dominated lasers show a generally symmetric distortion penalty response to laser frequency offset, whereas the response for adiabatic chirp dominated lasers is highly asymmetric. Furthermore, the extinction ratio for the latter class of lasers can be improved, in some cases, by the appropriate offset between laser and filter center frequencies     

Ultra-long distance wavelength-division-multiplexed solitontransmission using inhomogeneously broadened fiber amplifiers

The use of inhomogeneously broadened amplifiers for wavelength-division-multiplexed (WDM) optical soliton transmission is proposed. Dynamic gain equalization can be achieved through saturation, by adjustment of the time-averaged intensity of control lasers tuned between the WDM channels. The authors investigate numerically an example in which seven WDM channels at 2 Gb/s each are equalized using parameter values reasonable for germanosilicate core erbium-doped fibers     

Harmonic suppressed photonic microwave filter

This paper proposes a photonic microwave filter based on wavelength-division multiplexing (WDM) of multiple optical carriers and dispersive media. Harmonic suppression is obtained using nonuniform tap spacing to extend the filter free spectral range by a Vernier effect. The experimental results presented are in excellent agreement with theory.     

双通道光纤通信波分复用滤光片的设计与模拟

讨论了在采用薄膜干涉方法分（合）波时,其中的关键器件－薄膜干涉滤光片的设计和镀膜监控误差模拟,主要介绍了一个波分复用双通道薄膜干涉滤光片的设计原理、设计过程、滤光片的性能及影响因素分析。并进行了假定监控误差下的镀膜过程的模拟。     

增益调制型波长转换器消光比均衡的研究

利用半导体光放大器 (SOA)中交叉增益调制 (XGM)效应成功地实现了 62 2 Mb/ s和 2 .5Gb/ s信号的波长转换。对波长上 /下转换性能的研究表明 ,使用增益峰值波长比信号波长长的SOA可以有效地实现上 /下转换效率和消光比均衡 ,从而使这种类型的波长转换器在波分复用器(WDM)全光网中获得更大的应用     

WDM的过去、现在与未来

本文首先阐述了波分复用系统的发展史、发展现代WDM系统的条件,接着讲述了现代WDM所用的新技术即改善EDFA性能的技术、提高光源的稳定性、窄带光滤波器技术以及构成直流控制的可变光衰减器,最后阐述了第四代与第五代WDM系统以及WDM系统的发展趋势。     

An adaptive wavelength tunable optical filter employing anangle-tuned interference filter and an intelligent digital controller

This paper describes an adaptive wavelength tunable optical filter, which is composed of an angle-tuned interference optical filter and an intelligent digital controller. The new angle-tuned interference filter consists of a dielectric interference optical filter and a piezoelectric angle-tuning mechanism. It achieves quick wavelength switching within 2.5 ms in a 30 nm tuning range and a sufficiently low crosstalk less than -30 dB. The intelligent digital controller has two functions: wavelength tracking and wavelength channel selection. Combining these technologies, we have developed a practical low-cost tunable filter suitable for a post-optical-amplifier filter in a high-sensitivity detection system and a channel selector in a WDM system that requires 10-100 ms channel selection time. With a wavelength tracking operation, we have confirmed -35 dBm high-sensitivity detection in 20 nm wavelength range in a 10 Gb/s system. We have also confirmed a wavelength channel selection operation within 18 ms in a three-channel wavelength division multiplexed (WDM) system whose channel spacing is 4.4 nm     

Optical preamplifier receiver for spectrum-sliced WDM

Spectrum-slicing provides a low-cost alternative to the use of multiple coherent lasers for wavelength division multiplexing (WDM) applications by utilizing spectral slices of a single broadband noise source for creating the multichannel system. In this paper we analyze the performance of both p-i-n and optical preamplifier receivers for spectrum-sliced WDM using actual noise distributions, and the results are compared with those using the Gaussian approximation. This extends prior results of Marcuse for the detection of deterministic signals in the presence of optical amplifier and receiver noise. Although the methodology is similar, the results are considerably different when the signal is itself noise-like. For the case of noise-like signals, it is shown that when an optical preamplifier receiver is used, there exists an optimum filter bandwidth which minimizes the detection sensitivity for a given error probability. Moreover the evaluated detection sensitivity, in photons/bit, represents an order of magnitude (>10 dB) improvement over conventional detection techniques that employ p-i-n receivers. The Gaussian approximation is shown to be overly conservative when dealing with small ratios of the receiver optical to electrical bandwidth, for both p-i-n and preamplifier receivers     

Bidirectional erbium-doped fibre amplifier with non-reciprocaloptical filter

A 24 dB gain bidirectional erbium-doped fibre amplifier (EDFA) using a new non-reciprocal optical filter is demonstrated. Using the amplifier 2.5 Gbit/s×8 channel WDM signals were transmitted over 160 km long singlemode fibre. The measured penalty caused by multiple optical reflection was negligible     

Theoretical study of the gain equalization of a stabilized gainEDFA for WDM applications

We present a simple and efficient model which takes gain stabilization and internal filtering for gain equalization into account. This model allowed the optimization of the filter position in the doped fiber to obtain the best gain stabilization and lowest noise figure. Finally, we demonstrate that equalized and stabilized gain amplifiers are efficient devices for wavelength division multiplexing (WDM) transmissions     

10 Gbit/s four-channel wavelength- and polarisation-divisionmultiplexing transmission over 340 km with 0.5 nm channel spacing

The authors propose a novel WDM transmission technique combined with polarisation-division multiplexing (PDM) which doubles the frequency utilisation efficiency. This technique is used to transmit a 10 Gbit/s four-channel WDM signal with 0.5 nm channel spacing over 340 km and the signal is demultiplexed using an optical filter having 0.5 nm FWHM and a polarisation beamsplitter     

波分复用系统加密技术研究

波分复用系统是将多个独立的光波耦合复用到一根光纤中传输,从而更有效地提供带宽,让IP、ATM、SDH等数据通过统一的光纤层传输的系统。波分复用系统在改善网络性能的同时,也给网络的安全带来了一定的隐患。文中针对波分复用（WDM）自身特点及所面临的安全威胁,提出基于WDM的加密技术研究思路,为实现对WDM／OTN／ASON网络综合数据业务的安全保密奠定了基础。     

Demonstration of RSOA‐Based 20 Gb/s Linear Bus WDM‐PON with Simple Optical Add‐Drop Node Structure

We demonstrate a linear bus wavelength‐reused gigabit wavelength‐division multiplexing passive optical network (WDM‐PON) with multiple optical add‐drop nodes. A commercially available reflective semiconductor optical amplifier‐based WDM‐PON has a sufficient power budget to provide multiple optical add/drop nodes in 16 WDM channels. Sixteen 1.25 Gb/s WDM channels are successfully transmitted over 20 km of single‐mode fiber with four optical add/drop multiplexers, even with 32 dB reflection and chromatic dispersion in the link.     

无源波分复用设备在5G前传中的应用场景研究

5G BBU采用C-RAN与D-RAN相结合的建设模式,目前广东有限公司首选C-RAN这种业务集中部署的建设模式,然而C-RAN的建设模式对于前传光纤资源需求量非常大。本文从无源波分复用设备的原理出发,建立无源波分对光缆网的覆盖模型,对常见无源波分型号用所建立的模型进行分析,并给出相应的应用场景建议。     

基于应变的多模光纤可调谐光纤滤波器设计

可调谐光纤滤波器技术是波分复用系统的关键技术之一,对于发展全光通信网络和光纤传感具有极其重要的意义。提出了一种基于大芯径的多模光纤可调谐带阻滤波器,其制作方法是将包层/纤芯直径为125/105μm的特种多模光纤通过单模光纤接入光纤系统,实现单模-多模-单模(SMS)光纤结构,并使一端单模光纤与多模光纤熔接,另一端只是共轴对接而不焊接。在多模干涉原理的基础上,利用该结构对应变的敏感性实现可调谐光滤波。该可调谐滤波器的调制和解调借助于放大自发辐射(ASE)宽谱光源和光谱分析仪(OSA)实现。详细给出了该滤波器的理论仿真分析,并实验证实了该方案的有效性。