偏振无关集成声光可调谐滤波器及其应用

偏振无关集成声光可调谐滤波器(IAOTF)不但具有驱动功率低、调谐范围宽、插入损耗低以及可实现多波长同时选择等优点,还实现了输入光的偏振无关特性,在全光网络中极具应用潜力.文章设计了一种基于模分离器的偏振无关IAOTF,分析了它的基本结构及工作原理,并介绍了它在可调谐掺铒光纤激光器(EDFL)、光谱仪以及光开关中的应用.     

WDM光网络系统相干串扰与非相干串扰

同频串扰可以分为相干串扰与非相干串扰,本文提出了WDM光网络系统串扰相干性分析的数学模型,分析提出了相等的相干串扰代价和非干串扰代价下引起的WDM光网络系统功率代介的一致性,并与模拟相干串扰和非相干串扰结果进行了比较验证。实验结果表明,对应1dB功率代价下,WDM光网络系统对应相干串扰和非相干串扰代价容限步于－20dB和理论结果一致。串扰对于网络规模有一定的限制。     

WDM光网络相干串扰实验研究

同频串扰可以分为同源串扰和非同源串扰 ,文中分析了 WDM光网络系统相干串扰的起源与特征 ,设计并模拟实验研究了不同相干串扰代价下 ,WDM光网络系统的功率代价。对应 1 d B功率代价下 ,WDM光网络系统对应相干串扰代价容限小于 - 1 9.7d B,对于 WDM系统实用化组网具有一定参考价值     

WDM光网络非相干串扰实验研究

在WDM光网络系统中,节点如OXC和OADM采用的光器件其非理想性积累构成系统串扰问题。本文提出了WDM光网络系统中串扰问题分析的一般数学模型,根据模型分析比较了WDM光网络中相干串扰和非相干串扰的区别。实验研究了不同非相干串扰代价条件下,对应WDM光网络系统的功率代价。对应1dB功率代价下,实验得出WDM光网络对应非相干串扰代价容限小于－20.8dB的结果。实验结果对于WDM光网络组网规划有一定的参考意义。     

串扰对WDM光网络功率管理的影响

提出了一种新的节点功率管理方案,即同时考虑同频串扰和自发辐射噪声的总功率管理,针对两种节点隔离原则,给出了其数学模型,并进行了仿真计算,结果表明同频串扰对WDM光网络的规模和光信号的质量都有着重要的影响,而监测点的选取对信号质量影响不大。     

带通型全光纤声光可调滤波器

为了克服普通单模光纤只能实现带阻滤波器的问题,采用在单模光纤中间插入基模阻波器的办法实现了带通型全光纤声光可调谐滤波器.这种带通滤波器结构具有边带抑制比高、零频移、低偏振敏感、结构简单、易于封装等特点.     

Flattening of erbium-doped fibre amplifier gain spectrum using an acousto-optic tunable filter

An acousto-optic tunable filter is employed to flatten the gain spectrum of an erbium-doped fibre amplifier. A relatively flat gain spectrum of 15 nm in bandwidth with variations of less than 1 dB is obtained by simultaneously applying eight closely-spaced RF signals to the acousto-optic tunable filter.<>     

Acoustooptic tunable filters in narrowband WDM networks: systemissues and network applications

The system issues and network applications of acoustooptic tunable filters (AOTFs) are discussed. AOTFs are thought to be attractive system components in dense wavelength-division multiplexed (WDM) networks because of their broad continuous electronic wavelength tunability and narrow filter bandwidth. Their unique multiwavelength filtering capability adds a greater dimension of flexibility to network design. The characteristics of the AOTF are reviewed from a system viewpoint and the performance and capabilities of bulk-devices, integrated-optic devices, and fiber-based devices are discussed and compared. Three network applications using the acoustooptic tunable filters are described. The first application is as wavelength-tunable receivers or taps for local users in a subscriber loop distribution network. The second is as multiwavelength tunable receivers in a broadcast local-area cross-connect for packet communication with very-high-throughput data rate. The third is as wavelength-selective space-division switch fabric for routing and cross-connect between central offices. Future prospects and various issues for future research are also discussed     

Multiple channel operation of integrated acousto-optic tunable filter

Demonstrates an integrated bulk-wave acousto-optic tunable filter (1.0 nm FWHM) in a multiwavelength crosstalk measurement experiment. With 16 channels present, individual channel crosstalk was lower than -15 dB for both single-wavelength and dual-wavelength filtering. The RF drive power for 70% efficiency was 180 mW/wavelength.<>     

12 nm tunable WDM source using an integrated laser array

A 12 nm tunable source with up to 15 mW fibre coupled power has been fabricated by integrating four DFB lasers and a booster amplifier to provide a single output. High-yield and low-cost techniques are used, such as quarter-wave-shifted phase-masks for wavelength definition and an integration technique with only two regrowths     

Backscattering-induced crosstalk in WDM optical wireless communication

The crosstalk effect of aerosol backscatter on the performance of a wavelength-division-multiplexed (WDM) optical wireless communication (OWC) system is investigated, analyzed, and quantified. An OWC link could be a segment within a metropolitan area network (MAN) or a ground-station-to-space link of a satellite communication system. In these cases, a WDM transmitter and receiver are housed in one transceiver unit with parallel, or near-parallel, optic axes. The crosstalk at the receiver is caused by light from the transmitted signal of the same transceiver, which has been backscattered by molecules and aerosols in the atmosphere. This is exacerbated in the presence of fog and haze, in which case both the desired signal from another transceiver is attenuated by scattering and the backscatter-induced crosstalk increases. A bit-error-rate (BER) model is derived that takes into consideration the dominant noise sources, including backscatter-induced crosstalk and signal mixing with amplified stimulated emission (ASE) from an optical preamplifier at the receiver. The numerical calculations in this paper indicate that, in moderate fog, the BER may increase by an order of magnitude or more due to backscatter, depending upon the atmospheric extinction coefficient.     

WDM optical network testbed and distributed storage application

In this article we present the details of a generalized multiprotocol label switching controlled wavelength-division multiplexing (WDM) optical network developed under the Optical Network Focused Interest Group (ONFIG) program in Singapore. The WDM network is controlled through a GMPLS control plane that consists of CR-LDP, LMP, and OSPF-TE. We conducted various field trials on the GMPLS-capable WDM optical network testbed with the main focus on distributed storage service application. We developed and evaluated a distributed storage services application on the WDM optical network testbed and demonstrated that incorporating a lightweight data transport protocol with optical network control could be an efficient approach for data-intensive storage applications by exploiting the dynamic connection establishment and backup protection features.     

前向纠错在高速光网络系统中应用分析研究

前向纠错（FEC）能够较好地提高光网络性能,如增加光通信系统的传输距离,减少光端机发射功率,降低接收机灵敏度等。文中理论分析并比较了FEC在WDM光网络中两种应用形式（带内FEC和带外FEC）的纠错性能特性,满足不同速率高速光网络系统的应用需要,可以采用相应的FEC应用形式。     

Widely (132 nm) wavelength tunable laser using a semiconductor optical amplifier and an acousto-optic tunable filter

A widely wavelength tunable laser combining a semiconductor optical amplifier, an acousto-optic tunable filter and a Fabry-Perot etalon has been developed. It exhibited good characteristics over a 132 nm (1480-1612 nm) tuning range.     

Observation of WDM crosstalk in passive semiconductor waveguides

We show that passive InP-InGaAsP waveguides exhibit high nonlinear loss due to the highly energetic carriers generated by two-photon absorption. We have further demonstrated, for the first time, that due to this effect, severe crosstalk occurs between wavelength channels when they are transmitted through a semiconductor waveguide operated in the transparency region, at power levels used in typical wavelength-division-multiplexed (WDM) systems. Some solutions are proposed     

Modeling of in-band crosstalk in WDM optical networks

In this paper, we analyze three different simulation models which allow the impact of in-band crosstalk on the transmission performances of wavelength division multiplexing (WDM) optical networks to be evaluated: an accurate simulation (AS), a Gaussian correlated noise (GCN) model, and a Gaussian white noise (GWN) model. In the AS, an interfering channel is generated at each node and added to the signal after an optical filtering. The final result must be averaged with respect to the message transmitted on the interfering channels and to the phases of the optical carriers. In the GCN the crosstalk term is modeled as a Gaussian correlated noise, whose spectrum coincides with that of the interfering channel. This model can be further simplified if the noise is also assumed uncorrelated (GWN approximation). The results obtained by these simulation models are also compared with those produced by an analytical model allowing to evaluate the in-band crosstalk penalty     

Statistical analysis of crosstalk accumulation in WDM networks

Accumulation of inband crosstalk in all-optical networks is studied. By applying statistical methods, we have investigated how inband crosstalk accumulation influences the performance of optical networks of different configurations. Our study shows that there exists a delicate dependence between network topology and robustness with respect to accumulation of inband crosstalk. A method is proposed to design optical networks with optical paths satisfying a certain level of inband crosstalk performance     

Time-dependent analysis of acousto-optic tunable filters formultichannel optical switching

A time-dependent analysis of acousto-optic tunable filters (AOTF's) for multiwavelength optical-switching operations is presented, it explains the reason for the observed nonlinear behavior such as passband-pulling and quantifies the associated crosstalk performance degradation. The degradation of the filter performance is found to be due to copresence of the acousto-optic interaction profiles for different channels. Along with extensive Poincare-sphere analysis, the model also reveals time-dependent fluctuation of switching spectral responses, which calls for attention to the worst instances in the fluctuation for the wavelength division multiplexer (WDM) optical-switch application     

基于WDM/OCDMA-PON的光纤无线混合接入网结构

通过分析波分多址技术、码分多址技术的PON光纤接入技术和宽带无线技术相结合的混合光纤无线接入网技术的优越性和可行性,提出了基于WDM/OCDMA-PON光纤无线混合(HOWBAN)接入网技术的基本结构,给出WDM/OCDMA-PON光纤无线混合接入网系统的实现方案,提出了应用前景等.     

Modeling and performance analysis of a fiber Bragg gratinginterrogation system using an acousto-optic tunable filter

The performance of a fiber grating interrogation system using an acousto-optic tunable filter (AOTF) is analyzed. An equivalent linear circuit is presented to describe the system, which tracks the wavelength of a fiber Bragg grating (FBG) sensor in a FBG sensor array. From the model, the tracking resolution of a shot-noise-limited system has been determined for both transmissive and reflective interrogation of FBGs. An optimum ratio between the bandwidths of the FBG and the AOTF has been derived. Experimental results of a tracking system are presented to validate the theoretical predictions. The theory should also be suitable for interrogation systems using other forms of tunable bandpass filters for tracking the FBG wavelength