共查询到20条相似文献,搜索用时 34 毫秒
1.
A novel technique facilitating wavelength reused upstream transmission in a WDM passive optical network, eliminating wavelength source at ONUs, is proposed and experimentally demonstrated. A subcarrier frequency is used for downstream transmission and the pure optical carrier is filtered and reused for upstream transmission. The scheme requires only simple baseband receivers at both ONU and OLT terminals. 相似文献
2.
利用基带直调信号注入锁定半导体激光器产生全光上变频信号的研究 总被引:1,自引:1,他引:1
提出了一种将低速基带信号直调产生的宽谱信号,注入至用于上变频的分布反馈式半导体激光器(DFB-LD),利用调制信号光谱中的高阶分量对从激光器进行相位锁定,从而产生光学上变频信号的方法。对直调信号注入锁定DFB-LD产生光学上变频信号的机理进行了理论分析,完成了2.5Gb/s伪随机码基带信号通过直调并注入从激光器,分别产生了30,35,40GHz副载波频率的全光上变频信号的实验,并在时域和频域上,对上变频信号的特征进行了研究。该方案结构简单,无需高速外调制器及高频本振,具有集成潜力,理论上可产生更高载频(如60GHz),对目前的光-无线混合接入提供了一种可行的解决方案。 相似文献
3.
Lin Chen Wen S.C. Ying Li Jing He Hong Wen Yufeng Shao Ze Dong Yazhi Pi 《Lightwave Technology, Journal of》2007,25(11):3381-3387
We have proposed and experimentally demonstrated three different optical front-ends to implement in wavelength-division-multiplexing (WDM) radio-over-fiber (ROF) networks to minimize the cost of the ROF system. When the number of WDM channels is small, such as smaller than four channels, the simplest front-end to generate WDM optical millimeter (mm)-wave signals is to use only broadband direct-modulation laser (DML) for each WDM channel. In this case, the expensive external modulator can be removed. However, when the number of WDM channels is large, such as larger than four, the frond-end to generate WDM optical mm-wave signals can be realized by using an external modulator to upconvert simultaneously all channels after the WDM channel signals are multiplexed. In this way, the cost of the expensive external modulator will be shared by all channels. For seamless integration of WDM signals that come from the existing backbone with ROF system, a broadband external modulator can be used to upconvert WDM signals. 相似文献
4.
Reconfigurable 2.5-Gb/s Baseband and 60-GHz (155-Mb/s) Millimeter-Waveband Radio-Over-Fiber (Interleaving) Access Network 总被引:1,自引:0,他引:1
《Lightwave Technology, Journal of》2008,26(15):2506-2512
5.
This paper describes the design principles and performance of optical multi/demultiplexers (MUX/DEMUX's) in wavelength-division multiplexing (WDM) subscriber-loop systems over a 50- μm core diameter, graded-index (GI), multimode fiber, which employ analog baseband video transmission using laser diodes (LD's). In this WDM arrangement, requirements for MUX/DEMUX's are: 1) low insertion loss; 2) no signal degradation caused by optical interchannel crosstalk; 3) only a small amount of analog baseband signal degradation caused by the use of MUX/DEMUX; 4) a small size and simple structure capable of multiplexing three or four wavelengths; and 5) good stability. The newly developed 4-wavelength MUX/DEMUX satisfies the preceding requirements and is suitable for application to WDM subscriber-loop systems using analog baseband signals along with digital signals. 相似文献
6.
《Photonics Technology Letters, IEEE》2008,20(21):1814-1816
7.
Myunghun Shin Prem Kumar 《Photonics Technology Letters, IEEE》2007,19(21):1726-1728
We propose and demonstrate an optical microwave modulator that incorporates a low phase-noise optoelectronic oscillator (OEO) for frequency up-conversion in a radio-over-fiber system. A single Mach-Zehnder lithium-niobate waveguide modulator working as a local oscillator in a frequency-doubling OEO directly up-converts the baseband signals to a carrier band. We demonstrate frequency up-conversion to the 20-GHz band for optical analog signals in the intermediate-frequency (IF) band and for optical digital signals at 1.25 Gb/s. The measured transmission bandwidth for IF modulated signals is greater than 1.5 GHz for transmission over 50.5 km of single-mode fiber. 相似文献
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9.
《Microwave Theory and Techniques》2009,57(3):725-732
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11.
Jeung-Mo Kang Sang-Kook Han 《Photonics Technology Letters, IEEE》2006,18(3):502-504
A hybrid wavelength-division multiplexed/subcarrier multiplexed passive optical network (WDM/SCM-PON) which shares the same wavelength both up-link and down-link is presented by using a reflective semiconductor optical amplifier (RSOA) as a modulator. We investigated down-link of 622 Mb/s using distributed feedback laser diode with direct modulation and 100-Mb/s up-link using an RSOA as a modulator with 900-MHz SCM signal. In our scheme, a novel efficient and cost-effective WDM/SCM-PON using the same wavelength for down/up-link at each optical network unit is proposed and experimentally demonstrated. 相似文献
12.
《Lightwave Technology, Journal of》2008,26(15):2449-2459
13.
《Optical Fiber Technology》2014,20(4):428-433
A simple uplink transmission scheme with multiple-input direct detection and digital signal processing has been proposed and experimentally demonstrated for the time and wavelength division multiplexed passive optical networks (TWDM-PONs), to allow wavelength drift of lasers at the uncooled optical network units (ONUs). In our experiment, after passing by the commercial 100-GHz WDM demultiplexer, three 10-Gb/s NRZ signals with minimum signal wavelength separation of 50-GHz can be recovered successfully after 50-km standard single-mode fiber (SSMF) transmission. Simulation results are also obtained to analysis the receiver sensitivity at different wavelength separations and discuss methods improving power budget. 相似文献
14.
鉴于长距离隧道内复杂的无线传输环境,传统通信技术不能满足旅客高质量的通信需求,提出了一种基于波分复用无源光网络的光载无线(RoF)分布式隧道通信系统。采用波分复用技术实现不同业务在光域的物理隔离,协同分布式天线技术,在隧道内部提供高频无线接入,提升系统带宽的同时解决了隧道内部信号急剧衰减的问题。通过实验搭建了全双工的光载无线试验平台,实现了用光学的方法产生和传输载频为24 GHz的16/64QAM矢量信号,并且通过测量上下行链路的EVM值验证了方案的可行性。 相似文献
15.
《Photonics Technology Letters, IEEE》2008,20(17):1470-1472
16.
《Optical Fiber Technology》2013,19(5):405-409
A novel bidirectional lightwave transport system employing phase modulation (PM) scheme and light injection-locked distributed feedback laser diode (DFB LD) as a duplex transceiver for passive optical network (PON); as well as employing laser pointer lasers (LPLs) with directly modulating data signals for wavelength-division-multiplexing (WDM) visible light communication (VLC) is proposed and experimentally demonstrated. Impressive and low bit error rate (BER) operation is achieved for PON integration with VLC application. Such bidirectional PON integration with VLC system has been successfully demonstrated, which can not only present its advancement in PON/VLC application but also reveal its simplicity and convenience to be installed. Whereby, our proposed system is suitably applicable to the PON in combination with VLC system in wire and wireless transmission. 相似文献
17.
Yiqiao Song Xiaoping Zheng Hanyi Zhang Yili Guo Bingkun Zhou 《Photonics Technology Letters, IEEE》2008,20(9):685-687
We have proposed and experimentally demonstrated a scheme of all-optical broadband subcarrier demodulation in the up-link of wavelength-division-multiplexing (WDM) millimeter-wave radio-over-fiber systems. In this scheme, the subcarriers of all the WDM channels can be demodulated by only one optical demodulation module, hence its cost can be reduced remarkably. Because of its all-optical implementation, it can offer more bandwidth. The radio-frequency power degradation introduced by the channel dispersion is also avoided in this scheme even when the conventional simple double-sideband modulation method is employed in the base stations. 相似文献
18.
Optical integrated switching systems using collinear acoustooptic (AO) interactions for wavelength division multiplexing (WDM) systems are discussed. The AO switch module has excellent advantages compared to electrooptic switches. Optical WDM signals can be wavelength-selectively switched by frequency multiplexed surface acoustic waves. WDM switching systems are proposed as an application of this AO switch, and optical insertion loss, crosstalk, and optical frequency shift are discussed. Wavelength-selective characteristics in the AO module are established. The crosstalk from other wavelengths is found to be reduced by decreasing slightly the switching transfer efficiency. The wavelength-selective switching was experimentally demonstrated with a slab-type module of a 4-mm interaction region, where the WDM interval of 25.2 Å was realized. This wavelength interval can be decreased by increasing the interaction length 相似文献
19.
Xu Z. Wen Y. J. Zhong W.-D. Attygalle M. Cheng X. F. Wang Y. Lu C. 《Photonics Technology Letters, IEEE》2007,19(11):837-839
We propose a novel optical carrier-reuse scheme for the wavelength-division-multiplexed passive optical network. The scheme is based on a single delay interferometer (DI) at the remote node and reflective semiconductor optical amplifiers (RSOAs) at optical network units as the colorless devices for upstream transmission. The downstream subcarrier signals are optically separated by the DI for baseband detection of the downstream data and the separated optical carriers are used for seeding the RSOAs. Eight-channel upstream and downstream transmission is demonstrated at 1.25 Gb/s using the proposed scheme. The impact of optical carrier-to-subcarrier ratio of downlink signal and seeding light power on performance is also investigated 相似文献