Burst-mode optical transmitter with DC-coupled burst-enable signal for 2.5-Gb/s GPON system

In this paper, first burst-mode transmitter for 2.5-Gb/s gigabit-capable passive optical networks (GPON) system is evaluated. Small form factor (SFF) type optical network unit (ONU) generates 2.5-Gb/s optical eyes with commercial distributed feedback-laser diode (DFB-LD). For the fast burst signal access, burst enable (BEN) connection on the evaluation board utilizes DC-coupling configuration. Resultant optical output waveform shows 16.30 dB extinction ratio with wide eye opening for GPON mask test. No significant eye degradation is detected in high temperature operation and after 10 km distance transmission. Proposed GPON ONU successfully shows fast timing characteristics of 2.17 nsec for Tx enable stage and 1.17 ns for Tx disable stage.     

Demonstration of a WDM/TDM hybrid PON based on a colorless frame-level reach extender

We propose a hybrid passive optical network (PON) consisting of a 2.5 Gb/s reflective semiconductor optical amplifier (RSOA)-based 32 channel loopback wavelength division multiplexing-passive optical network (WDM–PON) and a colorless OEO-based frame-level reach extender (RE). This hybrid PON is designed to support a 128-way split over a 50 km transmission distance per single wavelength channel. We experimentally demonstrate the feasibility of this design through downstream and upstream packet transmission with a commercial gigabit-capable PON (GPON) product. Even if the colorless frame-level RE uses active devices at the remote node, it is still possible to increase the optical link budget through backward compatibility with existing GPON products. This design also provides wavelength conversion and an upstream burst-to-continuous mode conversion between the WDM–PON and GPON. The proposed hybrid PON can satisfy a packet loss ratio (PLR) of 10^?10 at the downstream and upstream transmission including the use of forward error correction (FEC).     

Analysis of upstream link bandwidth utilization in GPON with integrated network surveillance

We present a media access control protocol extension to integrate the physical layer surveillance concept into the transmission and the related management system in the Gigabit-capable passive optical network (GPON). We allocate an unused time slot for network surveillance depending upon its availability in the upstream GPON transmission convergence frame. We analyze the upstream link bandwidth utilization of the GPON system with network surveillance and show that there is a negligible amount of underutilization of link bandwidth as a result of this.     

Development of GPON upstream physical-media-dependent prototypes

This paper presents three new gigabit-capable passive optical network (GPON) physical-media-dependent (PMD) prototypes: a burst-mode optical transmitter, an avalanche photodiode/transimpedance amplifier (APD-TIA), and a burst-mode optical receiver. With these, point-to-multipoint (P2MP) upstream transmission can be realized in a high-performance GPON at 1.25 Gb/s. Performance measurements on the new burst-mode upstream PMD modules comply with GPON uplink simulations. The laser transmitter can quickly set and stabilize the launched optical power level over a wide temperature range with better than 1-dB accuracy. A burst-mode receiver sensitivity of -32.8 dBm (BER=10/sup -10/) is measured, combined with a dynamic range of 23 dB at a fixed APD avalanche gain of 6. Full compliance is achieved with the recently approved ITU-T Recommendation G.984.2 supporting an innovative overall power-leveling mechanism.     

A WDM Passive Optical Network With Centralized Light Sources and Multicast Overlay

We propose a novel wavelength-division-multiplexed passive optical network (WDM-PON) architecture to provide a downstream multicast overlay on the conventional point-to-point data service. The differential-phase-shift-keying multicast data is modulated on the same optical downstream carrier with the inverse return-to-zero point-to-point data signal, thus additional light sources are saved. Broadcast or multicast control is realized at the optical line terminal. For each WDM channel, part of the downstream power is re-used as the upstream data carrier, and thus realizes a colorless optical network unit. We successfully demonstrate the proposed WDM-PON with 10-Gb/s downstream point-to-point signals,10-Gb/s downstream multicast signals, and 2.5-Gb/s upstream signals.     

GPON中一种基于带宽需求的带宽分配算法

吉比特无源光网络（GPON）是接入网的最新发展趋势，动态带宽分配对提高GPON的服务质量、改进GPON系统时延及信道利用率等性能指标有着重要的意义，是GPON系统的关键技术之一，主要对GPON上行信道动态带宽分配技术进行研究，在分析GPON基于业务和基于T—CONT两种动态带宽分配算法的基础上提出一种新的改进型算法，新算法具有高效率和保证QoS的优点，并分析了这种算法的性能。     

光纤入侵信号检测及识别算法的嵌入式实现

提出了一种光纤入侵信号检测及识别算法,并根据 算法的处理时间及运算特点分解映射在现场 可编程逻辑门阵列(FPGA)和数字信号处理(DSP)组成的嵌入式处理器上进行实现。处理 流程分为3部分:首先对原始信号进行3Hz高通滤波,将经过高通滤波后的信号平均分成两部分分别由 两块DSP板并行处理以节省时间开销,且后续所有操作均采用并行方式,将滤波后数据进行 标准化并与检测阈值进 行比较,大于阈值则判为振动并置1,否则置0,从而得到单路检测结果;然后根据上述检测 结果提取用于 识别的数据;最后将数据输入识别模块进行机械、走路和镐刨信号的特征提取并得出识别结 果。实验结果表明, 本文算法可以有效检测和识别光纤入侵信号,且提高了运算速度,满足了光纤预警系统(OFPS )对检测及识别信号类型的实时性要求。     

Secrecy outage analysis in a hybrid cognitive relay network with energy harvesting

In this paper, we investigate the physical layer security of a hybrid cognitive relay network using an energy harvesting relay in presence of an eavesdropper. In the hybrid scheme, a secondary user (SU) as well as a cognitive relay works either in underlay or in overlay mode. In underlay, the transmit power of the SU as well as the relay is limited by the maximum acceptable interference at primary user (PU) receiver as required by an outage constraint of PU, a quality of service for PU. The secondary network consists of a decode and forward relay that harvests energy from radio frequency signal of secondary transmitter as well as PU transmitter to assist the SU in forwarding the information signal to the destination. A time switching relaying protocol is used at the relay. We evaluate the secrecy outage probability of secondary relay network assuming that channel state information of the interfering links from both the SU and relay transmitter to PU receiver is imperfect. Our results reveal the impact of imperfect channel state information, energy harvesting time, tolerable interference threshold, and PU outage constraint on the secrecy outage probability of SU.     

波分复用-光时分复用波长转换信号的消光比研究

对基于半导体光放大器(SOA)交叉增益调制(XGM)效应的全光波分复用一光时分复用(WDM—OTDM)转换后的两路时分复用输出信号的消光比(ER)特性进行了分析。研究了两路波分复用的输入抽运光和探测光的功率、波长、抽运光的消光比、数据速率以及半导体光放大器的偏置电流、腔长和模场限制因子对转换信号消光比的影响。模拟结果表明，增大抽运光输入功率，选择长波长抽运光，可以增加转换光相应信道消光比，但减小了相邻信道的输出消光比；增加抽运光消光比，可以提高转换光消光比，但各个信道增长幅度不同；减小探测光输入功率，选取短波长探测光波长，增加半导体光放大器的腔长和模场限制因子以及大的偏置电流可提高转换光消光比；对于两路或多路波分复用信号转换时分复用信号的过程中，一定要考虑转换光每个信道消光比的均衡。     

基于GI-POF实现宽带FTTx的WDM-GPON技术

介绍了光接入网和GPON技术,以及氟化梯度折射率聚合物光纤(PF-GI-POF)的特性,提出了基于PF-GI-POF实现宽带FTTx的WDM-GPON技术初步方案。     

Review on Dynamic Bandwidth Allocation of GPON and EPON

The passive optical network (PON) technology has been drastically improved in recent years. In spite of using the optical technology, the utilization of the entire bandwidth is a very challenging task. The main categories of PON are the Ethernet passive optical network (EPON) and gigabit passive optical network (GPON). These two networks use the dynamic bandwidth allocation (DBA) algorithm to attain the maximum usage of bandwidth, which is provided in the network dynamically according to the need of the customers with the support of the service level agreement (SLA). This paper will provide a clear review about the DBA algorithm of both technologies as well as the comparison.     

Channel Enlargement of PON System Using Nonreciprocal Multiplexing Filter Based on CWDM

We propose a nonreciprocal filter based on coarse wavelength division multiplexing (CWDM) that reduces the upstream channel insertion loss in a passive optical network (PON). We also propose a method to increase the number of channels/optical network units (ONUs) in PON systems using the proposed filter to reduce the service cost per subscriber. Experimental results show that the PON system with the proposed 4‐channel filter can reduce the power budget of the upstream and increase the number of ONUs by 3 to 4 times that of a conventional time‐division multiplexing PON.     

基于频谱分割的光码分多址接入系统实验研究

利用频谱分割技术进行了光码分多址接入 (OCDMA)系统传输实验。该实验的编解码器利用可调谐法 珀腔的不同自由谱域来区分不同用户 ,分析、测量了多址干扰对系统性能的影响 ,对系统中的光源、信道和编解码器的特性进行了讨论。测试表明 ,该接入系统在速率为 15 5Mb s ,MAI值是接收用户光功率 30倍的情况下 ,传输 11km普通单模光纤后 ,误码率优于 10 - 9。该系统实现简单 ,成本低 ,是全光接入的可选方案。     

输入信号消光比对光纤环形腔实现光信号复制的影响

首次从理论上推导利用光纤环形腔实现信号复制时输入信号消光比对环形腔输出信号消光比影响的定量关系,并在实验上观察到光信号中连续光基座引起复制信号消光比恶化的现象.实验测得了输入信号消光比对输出信号恶化程度的定量关系,与理论结果相符.通过减小连续光基座,实现了光纤环形腔对光信号的多次复制.利用掺铒光纤放大器(EDFA) 对环形腔进行功率补偿,及半导体光放大器(SOA)对输出信号进行功率均衡,实现了半功率复制10次以上.     

Reflective SOA-Based Bidirectional WDM-PON Sharing Optical Source for Up/Downlink Data and Broadcasting Transmission

We proposed and experimentally demonstrated the reflective semiconductor optical amplifier (RSOA)-based wavelength-division-multiplexed passive optical network (WDM-PON) scheme where not only up/downlink data services but also broadcasting service could be provided using a single optical source. In the proposed scheme, the digital signal and subcarrier multiplexing (SCM) signal for downstream were simultaneously modulated by a single distributed feedback laser diode and RSOA in optical network unit remodulated downstream source as an upstream. Without performance deterioration of digital signals both in up- and downstream, the proposed WDM-PON scheme can stably offer the SCM signal for broadcasting service. In the experiment, 1-Gb/s digital signals both for up- and downstream and 20-Mb/s SCM signal at 2.2 GHz for broadcasting were demonstrated in 10-km bidirectional link     

光接入网络中的数字信号处理技术

采用先进的数字信号处理(DSP)技术,在发射机和接收机分别引入预处理和后处理,以提高光接入网络的频谱效率并延长传输距离。研究了一种基于光超奈奎斯特(Super-Nyquist)滤波的类9状态正交振幅调制(9QAM)信号多模均衡(MMEQ)后端DSP算法,使用这种方案,能够有效提高频谱效率,实现了频谱效率高达4 bps/Hz的正交移相键控(QPSK)信号传输;还研究了一种基于数字SuperNyquist信号前端预处理的方案,此方案的优点是不需要光预滤波即可达到相同的频谱效率。使用一个采用直接调制激光器(DML)、直接探测和数字均衡技术的高速无载波幅度相位-64状态正交振幅调制(CAP-64QAM)系统,在20 km标准单模光纤(SSMF)上实现了创纪录的60 Gbit/s CAP-64QAM信号传输;使用相干探测,实现了速率高达100 Gbit/s的64状态正交振幅调制-正交频分复用(16QAM-OFDM)实时传输系统,解决了实时OFDM信号处理中的关键问题。     

A centralized-light-source WDM access network utilizing inverse-RZ downstream signal with upstream data remodulation

We propose and demonstrate employing inverse-return-to-zero (IRZ) downstream signal format to facilitate upstream data remodulation in a wavelength division multiplexing (WDM) passive optical network (PON) architecture with centralized light sources. The finite optical power in each downstream IRZ bit can be simply remodulated by the upstream data at the optical network unit. This can make each downstream and upstream pair share a single light source and such light reuse can be easily realized. An experiment on 10-Gb/s downstream IRZ signal generation, 2.5-Gb/s upstream signal remodulation, and two-way transmission is successfully demonstrated. The downstream/upstream signal performance in such a PON has also been analyzed, which is useful for system design.     

Can communications and sensors work together in one network?

With the development of both optical fiber-based communication and sensation, one interesting topic has been pointed out. How to connect those mountains of sensors to detect the signal in a large area, and how to make the cost of sensing system lower enough should be studied. A network of sensors is a good option. All sensing equipments, including the interrogators and the sensors, will be internetworking together. However, fiber optic communication networks have been developed very well over the past two decades. Is it necessary to rebuild a new network for sensors? In this paper, some new technologies in the two areas of fiber optic sensors and fiber optic communication will be addressed. Then, the available overlay architecture of a fiber optic sensors network will be presented. Finally, a polymorphous optical burst switching (POBS)-based architecture will be proposed, which can support all kinds of services, including digital data optical circuit/burst/packet switching and analog fiber optic sensor signal circuit/burst switching, etc.     

基于垂直腔面发射激光器的高速率并行光发射模块

报道了关于并行光发射模块的设计与制作.优化设计、制作并测试了12信道并行光发射模块,单信道传输速率可达3Gbit/s.采用波长为850nm的垂直腔面发射激光器作光源,激光器与驱动电路芯片直接用金丝连接.输出光束直接耦合进入12信道的光纤阵列中.采用小型化可插拔封装结构以便在应用中实现热插拔.模块的测试结果表明,在8mA的工作电流下,测到3Gbit/s的清晰眼图.     

10Gbit／sX4小型可插拔并行光收发模块的研制

研制了一款基于系统级封装技术的低成本、收发一体和可带电热插拔的4通道小型可插拔（QSFP）光模块,采用850nm垂直腔面发射激光器（VCSEL）阵列及其驱动器作为发射端,光电探测器（PD）阵列及其跨阻放大器（TIA）作为接收端,通过光路无源对准,实现了低成本光互连。高速度、高密度封装下的瞬态同步开关噪声、芯片间电磁干扰...