共查询到20条相似文献,搜索用时 62 毫秒
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Ali Shahpari Abdelgader Abdalla Ricardo Ferreira Giorgia Parca Jacklyn D. Reis Mario Lima 《Fiber and Integrated Optics》2014,33(3):149-162
AbstractThis article experimentally demonstrates a hybrid fiber–free-space passive optical network that enables high spectral density, aggregated capacity, and total throughput through ultra-dense wavelength-division multiplexing baseband and radio-over-fiber channels. Ultra-dense wavelength-division multiplexing 10-Gb/s Nyquist-shaped 16-ary quadrature amplitude modulation, 10-Gb/s radio-over-fiber orthogonal frequency-division multiplexing, and 8.75-Gb/s baseband orthogonal frequency-division multiplexing signals per user were transmitted through a maximum 40-km passive optical network, which includes a 6-m free-space optics link with acceptable performance. 相似文献
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We show that the amplifier bandwidth can be further increased and the gain spectrum can be tailored if one uses pumping with multiple laser wavelengths. We consider the wide-gain amplifier where four sets of multipumps are employed. We process two multiplexing techniques in long haul transmission cables where the number of channels is up to 9600 in ultrawide-wavelength-division multiplexing (UWWDM) with employment of the ultrawide-space-division multiplexing (UW-SDM) technique to merge the number of links up to 400 in the optical-fiber core over wide ranges of affecting sets of parameters. As well as the repeater spacing using a multi-pumping Raman amplifier, we investigate N R pumps in the optical pumping wavelength (from 1.36 to 1.44 μm) to amplify optical channels where the optical wavelength range (1.45–1.65 μm) satisfies near infrared optical transmission region. 相似文献
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To the best of our knowledge, we explore, for the very first time, the performance using Raman-EDFFA hybrid amplifier for super dense multiplexing system. We evaluate the system in terms of flat gain, noise figure, and good rating quality factor for L-band. A highest flat gain of 26.01 dB is observed over a wavelength range of 1,578 to 1,640 nm with a smaller variation of 1.5 dB without using any cost influence techniques. Further, we also observe that an input power level of ?25 dB is quite suitable for acceptable amplification. 相似文献
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A spectral amplitude coded-optical code division multiplexing time division multiplexing(SACOCDM/TDM) passive optical network(PON) for upgrading the traditional TDM PON is proposed.To the best of our knowledge,our work is the first to report on the use of both spectral and orthogonal code domains,which are transparent to optical network unit(ONU) for hybrid PON,in order to upgrade TDM PON seamlessly.The fewer encoder/decoders and cheaper optical source under the conditions of high bite rate and large ONU ac... 相似文献
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An 8‐channel hybrid (de)multiplexer to simultaneously achieve mode‐ and polarization‐division‐(de)multiplexing is proposed and demonstrated experimentally on a silicon‐on‐insulator platform to improve the link capacity of an on‐chip optical interconnect. The present hybrid (de)multiplexer has four channels for each polarization. A polarization beam splitter based on a three‐waveguide coupler is used to combine/separate the fundamental modes of TE‐ and TM‐polarizations (TE0 and TM0). Six asymmetric directional couplers are cascaded for (de)multiplexing the high‐order modes (TE1, TE2, TE3, TM1, TM2, and TM3). The experimental results show all eight channels have low loss and low crosstalk (<−10 dB) over a ∼ 30 nm wavelength range. 相似文献
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For increasing the data density of holographic data storage (HDS), combining more than two multiplexing techniques is effective. This is also true in self-referential holographic data storage (SR-HDS) that enables holographic recording purely with a single beam. In this paper, a focus-shift multiplexing technique is applied to \(xy\)-shift multiplexed SR-HDS, the feasibility of which has been shown in our previous work. The focus-shift multiplexing technique enables the multiplexing of datapages by slightly changing the focal length of the objective lens. However, the required focus-shift distance for multiplexing and the implementation method of the focus-shift have not been clarified. First, the focus-shift selectivity is investigated by the numerical simulations. In the case where the focus-shift multiplexing technique is applied to \(xy\)-shift multiplexed SR-HDS, the inter-page crosstalk properties are clarified to decide the recording layout that can achieve a low-crosstalk readout. Second, the technique of displaying an additional phase pattern onto the spatial light modulator (SLM) is introduced, which is a focus-shift method without any special optical components, such as varifocal lenses. Finally, we investigate the relationship between the accuracy of the focus-shift and the parameters of SLM. 相似文献
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AbstractPerformance optimization of a duty-cycle division multiplexing system over 8- and 40-channel wavelength division multiplexing networks is reported in this article. The modified duty-cycle division multiplexing system with optical domain multiplexing using a dual-drive Mach–Zehnder modulator is simulated with two and three users per wavelength. Using conventional dispersion compensation, the 40 × 40-Gbps system with two and three users per channel can support 240 and 160 km of transmission distance, respectively. The dispersion management technique based on a chirped fiber Bragg grating is proposed for a 40 × 3 × 13.33-Gbps duty-cycle division multiplexing/wavelength division multiplexing system that allows double the transmission distance compared to conventional technique. 相似文献
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Fiber Bragg grating-based self-referencing technique for wavelength-multiplexed intensity sensors 总被引:1,自引:0,他引:1
An amplitude-phase-conversion self-referencing technique for intensity-modulated photonic sensors that uses two different-wavelength fiber Bragg gratings is presented. With this technique, the system response has been demonstrated to be almost unafffected by network power variations as high as 90% of the total power launched by the source. We prove the multiplexing capability of this type of self-referenced fiber sensor by wavelength-division multiplexing two of them in a star network. A tunable fused biconical wavelength-division multiplexer is used for sensor addressing at the detection block, providing both good isolation and low cross-talk values. 相似文献
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Abstract A unique high-speed, protocol-independent, single-mode fiber wavelength division multiplexing network is presented, which operates over a hybrid bus/ring topology that supports Ethernet and many other protocols simultaneously and bidirectionally. 相似文献
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Up to eight holograms are successively recorded at maximum repetition rates of 20kHz. A multiply Q-switched ruby laser is used to produce the series of coherent light pulses for hologram exposure. All holograms are recorded on the same plate. Image separation of different holograms is achieved by spatial multiplexing using a rotating disk with apertures directly in front of the holographic plate. The performance of the technique is demonstrated by reconstructions of a hologram series taken of laser produced cavitation bubbles following optical breakdown in water. 相似文献
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Dong Liang Ahmad W. Mohammad Chris Roeloffzen Qinggui Tan Li Li Xiaojun Li Bin Shao Bo Zhang Xiangke Deng Feiteng Zheng Lennart Wevers Robert Grootjans Paul Kapteijn Roelof Bernardus Timens Rick Heuvink Sami Musa 《Laser \u0026amp; Photonics Reviews》2024,18(2):2200952
High-throughput satellite (HTS) is an ideal way to realize cross-regional massive, multifaceted digital exchange services, and it requires a signal processing module that can be massively multiplexed and has high flexibility. Due to the limitations of the frequency characteristics, microwave integrated circuits are difficult to meet this requirement. One solution to this problem is photonic integrated circuits (PICs). However, full-size PIC satellite payloads containing main optoelectronic components are extremely challenging to implement on monolithic or hybrid integrated platforms. Here, the study demonstrates a hybrid integrated on-chip microwave-photonic satellite repeater with large-scale multiplexing potential and high flexibility. This is a demonstration of a hybrid integration of a InP/Si3N4 external cavity laser, arrayed InP modulators, and semiconductor optical amplifiers (SOAs), as well as multifunctional Si3N4 signal processors, to fulfill a 1 × 4 Ka-band repeater module with on-chip arrayed frequency down-conversion and outstanding narrowband photonic channelization. When combined with the full-chip photonic RF repeater, broadband, highly integrated, and cost-effective communications satellite payloads will become realizable more quickly in the near future. 相似文献
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Gamal A. Hussein Saied M. Abd El-atty Osama Aly Oraby Abd El-Naser A. Mohamed Ahmed S. Elkorany Ibrahim Eldokany Moawad I. Dessouky El-Sayed M. El-Rabaie Saleh A. Alshebeili F.E. Abd El-Samie 《Optik》2014
Optical code division multiple access (OCDMA) is a promising operational system for future backhaul optical networks especially for switching and optical signal multiplexing. However, OCDMA operation is restricted by multiple access interference (MAI) due to the asynchronous nature of transmission. In this study, we discuss an efficient MAI technique for OCDMA systems that depends not only on using hybrid frequency shift keying (FSK) modulation but also on employing the double padded modified prime code (DPMPC) as a signature sequence. MAI cancellation is performed by subtracting a reference signal from the received signal of the desired user. The simulation results show that the performance of the FSK-OCDMA technique is superior to the performance of the PPM-OCDMA technique. Furthermore, the obtained results illustrate that the FSK-OCDMA technique is able to accommodate a large number of simultaneous active users with low error-rate. 相似文献
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This article presents a review of the strategies that have been both demonstrated and proposed for the multiplexing of multiple noninterferometric optical fiber point sensors to form a sensor network. The focus, which avoids consideration of interferometric sensor types, enables discussion of conventional multiplexing tech niques, namely, spatial, time division, frequency division, and wavelength division prior to dealing with combined or hybrid schemes, which exhibit the potential for increased multiplexing gain. Specific advantages and potential drawbacks of the different strategies are provided together with an indication of the number of point sensors that each multiplexing scheme can support. 相似文献
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Ahmed Nabih Zaki Rashed Abd-Elnaser A. Mohammed Osama M. A. Dardeer 《中国光学快报(英文版)》2014,12(5):50602-14
A hybrid optical switch (HOS) with physical layer of wavelength division multiplexing and optical code division multiplexing (WDM/OCDM) scheme is proposed. An additional feature to the HOS than optical cross connect (OXC) is that the controller can process requests for both circuit establishment and burst scheduling. In our study, the measurement criteria of HOS are the blocking probability, probability of error, and probability of outage. To simplify the analysis, no distinction is made between a circuit in progress and a burst in progress. Moreover, a minimum fit (MinF) resource allocation strategy is applied in order to increase the bandwidth efficiency and control the multiplexing interference of the OCDM. A 2D Markov model for the HOS is presented using the MinF strategy. Numerical results reveal that the code parameters and the resource allocation strategy greatly affect the performance. Certain periority can be achieved by assigning shorter codes to high periority users and longer codes to low periority users. Also, the probability of error and outage are reduced bv aonling the MinF strategy. 相似文献
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We propose a hybrid multiplexing method for volume holographic correlators based on the combination of orthogonal random phase modulation of an object beam and two-dimensional angular multiplexing of a reference beam. This method implements storing multiple groups of library images in a single storage location and outputting multiple groups of correlation spots by switching the modulation phase masks. Three experiments are designed to test the validity of this method. 相似文献
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In this paper, CO2 laser–metal active gas (MAG) hybrid welding technique is used to weld high strength steel and the optimized process parameters are obtained. Using LD Pumped laser with an emission wavelength of 532 nm to overcome the strong interference from the welding arc, a computer-based system is developed to collect and visualize the waveforms of the electrical welding parameters and metal transfer processes in laser–MAG. The welding electric signals of hybrid welding processes are quantitatively described and analyzed using the ANALYSATOR HANNOVER. The effect of distance between laser and arc (DLA) on weld bead geometry, forming process of weld shape, electric signals, arc characteristic and droplet transfer behavior is investigated. It is found that arc characteristic, droplet transfer mode and final weld bead geometry are strongly affected by the distance between laser and arc. The weld bead geometry is changed from “cocktail cup” to “cone-shaped” with the increasing DLA. The droplet transfer mode is changed from globular transfer to projected transfer with the increasing DLA. Projected transfer mode is an advantage for the stability of hybrid welding processes. 相似文献
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叙述了近年来在天津大学研究及开发光互连网络的情况。这些研究围绕着解决信号传输中的延迟和通信带宽,开展的研究工作有:完成包括64个处理器的光电混合处理器阵列系统;giga—bit/s机群系统光互连链路;在链路中采用时分复用技术(TDM),实现了“虚拟并行传输”;在链路中设计了硬件路由功能,并组成光环网;在网络系统中实现波长路由,并建立了波长路由双环网,采用该技术可以避免路由延迟;在光互连网络中应用了MEMS光开关,实现了星型一环形二级结构;用同步光传输技术实现了多通道数据传输卡。 相似文献