一种基于反射式SOA的FBG传感解调方法

提出一种基于反射式半导体光放大器（R-SOA）的光纤Bragg光栅（FBG）传感解调方法。周期性调谐R-SOA与可调谐FBG构成的窄带可调谐激光器,当其输出波长与FBG传感器反射波长一致时,由光电探测器输出光电流最大判断2个FBG周期的匹配并完成对传感FBG周期的测量。测量结果表明,FBG传感器中心波长在1 551.9...     

放大自发辐射注入波长锁定法布里-珀罗激光器

波分复用无源光网络(WDM-PON)被认为是接入网的最终解决方案,基于放大自发辐射(ASE)注入波长锁定法布里-珀罗(F-P)激光器的WDM-PON由于其价格低廉和容易实现颜色无关操作而受到极大关注.实验研究了ASE注入波长锁定F-P激光器的ASE增益、边模抑制比(SMSR)和相对强度噪声(RIN)随F-P激光器注入电流和ASE注入功率的变化关系,理论模拟了ASE注入功率和增益一定时,F-P激光器注入电流随其前端面反射率的变化关系,并从实验上进行了验证.研究结果表明,当F-P激光器的注入电流为阈值电流的1.3～1.7倍时,能获得满足应用需要的相对强度噪声和边模抑制比.对于一定的ASE注入功率和输出功率,存在使注入电流最小的最佳前端面反射率.     

Polarization optical bistability induced by TM mode injection to aDFB laser with complex coupled coefficient

A novel method is proposed to produce an optical bistability by using a dynamically stable complex coupled DFB (CC-DFB) laser with TM mode injection. In this paper polarization optical bistabilities are analyzed in detail using coupled mode equations and rate equations for the CC-DFB lasers considering the longitudinal hole burning and carrier dependent complex coupling coefficients. Several parameters reflecting the physical features of a complex coupled DFB laser are discussed. It is shown that for a CC-DFB laser the polarization bistability induced by the TM mode injection is much stronger for the antiphase of complex coupling than that for the in-phase. In addition, the influences of initial coupling condition for gain grating structure on the optical bistability are also investigated considering both cases of the antiphase and in-phase     

Broad-band light source using mutually injected Fabry-Pe/spl acute/rot laser diodes for WDM-PON

We propose and demonstrate a new broad-band light source (BLS) for a wavelength division multiplexing-passive optical network (WDM-PON) based on the wavelength locked Fabry-Pe/spl acute/rot laser diodes (F-P LDs). By mutual injection between two antireflection-coated F-P LDs, we realized a broad-band light with a low relative intensity noise. By using the proposed BLS for wavelength locking of the F-P LD, we achieve color-free operation of the optical network termination with Manchester coded data. We also demonstrate a WDM-PON based on the proposed BLS.     

利用激光偏振特性的电子散斑面内全场位移测量技术的研究

提出一种能够同时测量面内全场位移的电子散斑测量光路结构,解决了面内全场位移在瞬态和不可重复情况下无法测量的问题。将激光束分成四路照明光,分别安排在水平和垂直平面内,利用激光器的偏振特性安排光路,使水平平面内两束光的偏振方向相同,垂直平面内两束光的偏振方向相同,但这两个平面中的偏振方向又互相垂直。对转动圆盘内位移测量,取得了满意的结果,用一幅散斑图同时得到了表示水平和垂直分量的散斑条纹     

Frequency modulation on single sideband using controlled dynamics of an optically injected semiconductor laser

Nonlinear dynamics of an optically injected semiconductor laser is applied to photonic microwave generation. By properly adjusting the injection conditions, the optical frequency of the slave laser is first locked to the master laser. The slave laser is then driven into a periodic dynamical state, resulting in a single-sideband (SSB) microwave modulation on the optical carrier. The frequency of the SSB can be controlled by the optical injection strength and detuning. Frequency-modulated SSB can, thus, be obtained from a modulated injection. In this work, we experimentally investigate the generated SSB in terms of its broad tunability and fast modulation response. The results suggest application of this system in radio-over-fiber and optical subcarrier multiplexing technologies when microwave frequency modulation or frequency-shift keying is employed.     

Improving upstream transmission performance using a receiver with decision threshold level adjustment in a loopback WDM-PON

We have experimentally demonstrated that the use of an optical receiver with decision threshold level adjustment (DTLA) improved the performance of an upstream transmission in reflective semiconductor optical amplifier (RSOA)-based loopback wavelength division multiplexing-passive optical network (WDM-PON). Even though the extinction ratio (ER) of the downstream signal was as much as 9 dB and the injection power into the RSOA at the optical network unit was about ?24 dBm, we successfully obtained error-free transmission results for the upstream signal through careful control of the decision threshold value in the optical receiver located at optical line terminal (OLT). Using an optical receiver with DTLA for upstream signal detection overcame significant obstacles related to the injection power into the RSOA and the ER of the downstream signal, which were previously considered limitations of the wavelength remodulation scheme. This technique is expected to provide flexibility for the optical link design in the practical deployment of a WDM-PON.     

Tunneling injection quantum-dot lasers with polarization-dependent photon-mediated carrier redistribution and gain narrowing

A theoretical and experimental study of a particular transverse-electric (TE) mode lasing mechanism of a tunneling injection InP quantum-dot (QD) laser is reported. In the experiment, the TE mode lasing action takes place at the first excited state of InP biaxially compressively strained QDs. This QD state is coupled to the ground state of two tensile-strained InGaP quantum wells (QWs) although the tensile-strained QW structure favors the transverse-magnetic (TM) polarization light emission. The measured TE and TM modal gain spectra show a typical QW gain evolution behavior at low injection currents, which can be theoretically modeled by the quasi-equilibrium of carrier distribution. When the injection current is increased near threshold, a TE gain narrowing and a simultaneous TM gain pinning are observed in the measured modal gain spectra, which cannot be explained via the quasi-equilibrium model. We propose a polarization-dependent photon-mediated carrier redistribution in the QD-coupled-QW structure to explain this TE and TM gain evolution behavior. When the injection current is just below threshold, the strong carrier depletion via stimulated emission due to coupling between the InP QD and InGaP QW states plays an important role in carrier redistribution, which depends on the optical transition energy and polarization. This concept of the polarization-dependent photon-mediated carrier redistribution explains the TE gain narrowing and TM gain pinning behavior. In addition, a coupled rate equation model is established, and the calculated polarization power ratio based on the coupled rate equations explains the experimental observation.     

Application of optical frequency comb generation with controlled delay circuit for managing the high capacity network system

The generation of optical frequency comb (OFC) with novel controlled delay circuit is presented in this study. The proposed OFC is based on a single laser source which is cascadingly connected with three modulators; all the modulators are tailored by RF signal while incorporating no phase shifter or electrical/optical amplifier. The proposed OFC is used as a source at optical line terminal (OLT) of WDM-PON setup, which serves multiple users with a single laser source making OLT side very cost effective. 41 comb lines with over 40 dB tone to noise ratio and high side mode suppression ratio, least amplitude difference of under 0.3 dB, with cost effective setup is an attractive source for WDM-PON system. The frequency spacing is 32 GHz between OFCG lines which provides enough bandwidth for data transmission, the overall bandwidth provided by this scheme is 1.2 THz. Using DPSK modulation technique across each frequency of OFCG, the controlled delay circuit increases the capacity by factor two, whereas by deploying DQPSK modulation technique, it quadrupled the overall capacity in downlink transmission. Thus, the system offers four times increased capacity ∼1.6 Tbps by deploying state of the art technique for modulation and generating OFC with controlled delay. The average power penalty in the downlink and uplink transmission is 2.5 dBm and 3.13 dBm.     

An Automatic Wavelength Control Method of a Tunable Laser for a WDM-PON

We propose a novel automatic wavelength control method of a tunable laser for a wavelength-division-multiplexed passive optical network (WDM-PON). By sending a low-power amplified spontaneous emission light generated from a broadband light source (BLS) to a tunable laser through a wavelength-division multiplexer, we match the wavelength of the tunable laser to a peak transmission wavelength of the multiplexer. The deviation of the wavelength of the tunable laser was less than 0.05 nm from the center of the target channel. We demonstrate up to 10-Gb/s transmission in a WDM-PON by using the proposed method. We also show that system impairments induced by the BLS are negligible.      

光纤型宽调谐中红外激光光源的设计与研制

报道一种光纤型宽调谐中红外差频产生（DFG）激光光源,该系统分别以掺镱光纤激光器（YDFL）和掺铒光纤激光器（EDFL）作为泵浦和信号源。为拓宽基频光调谐范围,采用了4个不同工作波段的YDFL,并通过电控光开关实现段间的快速切换,总调谐范围为1040-1110nm;采用电控偏振控制器 (ECPC)分别对基频光偏振态进行精确快速控制,以提高系统转化效率;利用PID算法和负反馈技术分别稳定泵浦LD温度和驱动电流,并将其工作状态通过LCD实时显示。测试结果表明,该中红外激光系统可在3.04-3.72μm内连续调谐。     

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.     

Data transparent reconfigurable optical interconnections usingpolarization switching in VCSEL's induced by optical injection

We demonstrate a data transparent reconfigurable optical interconnection system based on optical injection controlled polarization switching in a master-slave vertical-cavity surface-emitting laser (VCSEL) configuration. A 140-Mb/s data stream generated by the slave VCSEL is redirected by an anisotropic diffractive optical element depending on the polarization state of the emitted light. The polarization of the slave laser is controlled by injecting an orthogonally polarized optical signal from a master laser. The current modulation of the master VCSEL and the subsequent polarization switching of the slave VCSEL occur at 40 MHz. In our setup, both the data rate and the optical interconnection reconfiguration rate are limited by the electronic drive circuitry and could in principle attain the gigahertz range     

A novel symmetric 10 Gbit/s architecture with a single feeder fiber for WDM-PON based on chirp-managed laser

We propose the single feeder fiber architecture for wavelength division multiplexing passive optical network(WDM-PON)based on directly modulated chirp managed laser(CML).The downlink(DL)signal output from the laser is converted to return-to-zero(RZ)differential phase shift signal using a pulse carver.The downstream signal is reused as a carrier for the upstream using intensity modulation technique.Simulation results show the error-free performance at symmetric data rate of 10 Gbit/s per channel with negligible power penalty and improved receiver sensitivity for the uplink(UL),over 25 km standard single-mode fiber(SSMF).A low-cost and reduced circuitry network design is implemented on a single feeder fiber with the elimination of differential encoder and one external modulator.     

Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network

It is anticipated that more than 75 Mb/s per subscriber is required for the convergence service such as triple-play service (TPS). Among several types of high-speed access network technologies, wavelength-division-multiplexing passive optical network (WDM-PON) is the most favorable for the required bandwidth in the near future. Furthermore, WDM technologies, such as athermal arrayed-waveguide grating (AWG) and low-cost light source, have matured enough to be applied in the access network. In this paper, the authors propose and implement a WDM-PON system as a platform for TPS. The system employs an amplified spontaneous emission (ASE)-injected Fabry-Pe/spl acute/rot laser diode scheme. It has 32 channels of 125 Mb/s and adopts Ethernet as Layer 2. Multicast and virtual local area network features are used for the integration of services such as Internet protocol high-definition broadcast, voice-over Internet protocol, video on demand, and video telephone. The services were demonstrated using the WDM-PON system.     

Single fiber colorless symmetric WDM-PON architecture using time interleaved remodulation technique for mitigating Rayleigh backscattering resilience

A time interleaved differential phase shift keying (DPSK) remodulation technique is proposed to mitigate the effect of Rayleigh backscattering (RBS)-induced noise in a single fiber colorless wavelength-division-multiplexing passive optical network (WDM-PON). In order to achieve a cost effective optical network unit (ONU) solution without dedicated laser sources for upstream signals to provide optimum symmetric capacity in a colorless WDM-PON, remodulation becomes the core attraction. Also as the performance of colorless WDM-PON systems suffers from the transmission impairments due to RBS, it is mitigated by using this remodulation scheme. Simulation results show that downstream and upstream signals achieve the error-free performance at 10 Gbit/s with negligible penalty, and enhance the tolerance to RBS-induced noise over a 25 km single-mode fiber.     

基于认知无线电的ROF-PON光无线接入技术

文章提出了基于认知无线电的光纤无线通信系统-无源光网络(ROF-PON)光无线接入网络系统结构。该方案光纤中直接传输射频信号。光层可采用波分复用-无源光网络(WDM-PON)技术(也可以是一个定制的光接入层)。远端的光网络单元(ONU)将得到的传感信息回传到中心局(CO),应用认知无线电技术进行处理。频谱感知和信道接入等都在CO处理,降低了整个系统的复杂度,发挥了光纤无线通信系统(ROF)的优势,也发挥了认知无线电在管理频谱方面的特长。     

Switching of Lasing Circular Polarizations in a (110)-VCSEL

We discuss our demonstration of gigahertz switching of lasing circular polarizations in a (110) GaAs-based vertical-cavity surface-emitting laser (VCSEL) obtained by optical spin injection. The (110)-VCSEL's significantly longer spin relaxation time (2.8 ns) than its carrier lifetime (0.42 ns) enabled it to consecutively oscillate in orthogonal circular polarizations with a high degree of circular polarization, when the time delay between two optical pump pulses with orthogonal circular polarizations was longer than 1 ns. Rate equation analysis closely reproduced the measured results.     

采用短相干光源的动态斐索干涉仪

为了实现斐索型干涉仪的动态干涉测试,研究了一种采用短相干光源的动态斐索干涉仪。以中心波长为638 nm、带宽为0.1 nm的二极管泵浦固体激光器作为光源,与偏振延迟装置结合得到一对短相干正交线偏振光,通过调节光源模块中两支线偏振光的光程差来匹配斐索干涉腔的长度,从而获取一对光程差为0的相干光束。使用偏振相机采集得到四幅位相依次相差/2的移相干涉图,按照四步移相算法解算相位,恢复待测元件的表面面形。采用光强归一化算法有效地抑制了偏振态误差导致的移相干涉图光强不一致在最终恢复波面中引入的一倍频波纹误差。采用琼斯矢量和琼斯矩阵分析了干涉图对比度与s光和p光光强比值的关系,并分析了1/4波片方位角误差对最终恢复波面的影响。利用该装置和Zygo GPI XP型干涉仪测量了同一块光学平晶,其均方根值相差0.024,峰谷值相差0.026。     

论OFDM-PON与WDM-PON

论述正交频分复用无源光网(OFDM-PON)与波分复用无源光网(WDM-PON)的联系和区别,指出WDM-PON实际上是一种光接入网的物理层技术,它只有和别的媒质访问控制(MAC)技术结合起来才能完成数据通信系统和网络的功能.而OFDM-PON是工作于正交频分多址(OFDMA) MAC技术的光接入网,它的光网络单元(O...