<li id="0wkme"></li> An Optical fiber amplifier is a key component for enabling efficient transmission of wavelength-divisionmultiplexed(WDM)signalsoverlongdistances.Eventhough many alternative technologies were available, erbium-doped fiber amplifiers won theraceduringtheearly1990sandbecameastandardcomponentforlong-haulopti- caltelecommunicationssystems.However,owingtotherecentsuccessinproducing low-cost, high-power, semiconductor lasers operating near 1450 nm, the Raman amplifiertechnologyhasalsogainedprominenceinthedeploymentofmodernlight- wavesystems.Moreover,becauseofthepushforintegratedoptoelectroniccircuits, semiconductor Optical amplifiers, rare-earth-doped planar waveguide amplifiers, and silicon Optical amplifiers are also gaining much interest these days.
標(biāo)簽： Propagation Light Media Gain in
上傳時(shí)間： 2020-05-27
上傳用戶(hù)：shancjb
Ever since ancient times, people continuously have devised new techniques and technologies for communicating their ideas, needs, and desires to others. Thus, many forms of increasingly complex communication systems have appeared over the years. The basic motivations behind each new one were to improve the transmission fidelity so that fewer errors occur in the received message, to increase the transmission capacity of a communication link so that more infor- mation could be sent, or to increase the transmission distance between relay sta- tions so that messages can be sent farther without the need to restore the signal fidelity periodically along its path.
標(biāo)簽： Communications Essentials Optical
上傳時(shí)間： 2020-05-31
上傳用戶(hù)：shancjb
Visible light communications (VLC) is the name given to an Optical wireless communication system that carries information by modulating light in the visible spectrum (400–700 nm) that is principally used for illumination [1–3]. The communications signal is encoded on top of the illumination light. Interest in VLC has grown rapidly with the growth of high power light emitting diodes (LEDs) in the visible spectrum. The motivation to use the illumination light for communication is to save energy by exploiting the illumination to carry information and, at the same time, to use technology that is “green” in comparison to radio frequency (RF) technology, while using the existing infrastructure of the lighting system.
標(biāo)簽： Communication Visible Light
上傳時(shí)間： 2020-06-01
上傳用戶(hù)：shancjb
Wavelength division multiplexing (WDM) refers to a multiplexing and transmission scheme in Optical telecommunications fibers where different wavelengths, typically emitted by several lasers, are modulated independently (i.e., they carry independent information from the transmitters to the receivers). These wavelengths are then multiplexed in the transmitter by means of passive WDM filters, and likewise they are separated or demultiplexed in the receiver by means of the same filters or coherent detection that usually involves a tunable local oscillator (laser).
標(biāo)簽： Multiplexing Wavelength Division
上傳時(shí)間： 2020-06-01
上傳用戶(hù)：shancjb
Wireless networking is undergoing a transformation from what has been primarily a medium for supporting voice traffic between telephones, into what is increasingly becoming a medium for supporting traffic among a variety of digital devices transmitting media of many types (voice, data, images, video. etc.) Wireline networking underwent a similar transformation in the 1990s, which led to an enormous build-up in the capacity of such networks, primarily through the addition of new Optical fiber, switches and other infrastructure.
標(biāo)簽： Multiusers Detection Wireless Networks
上傳時(shí)間： 2020-06-01
上傳用戶(hù)：shancjb
Identification is pervasive nowadays in daily life due to many complicated activities such as bank and library card reading, asset tracking, toll collecting, restricted access to sensitive data and procedures and target identification. This kind of task can be realized by passwords, bio- metric data such as fingerprints, barcode, Optical character recognition, smart cards and radar. Radiofrequencyidentification(RFID)isatechniquetoidentifyobjectsbyusingradiosystems. It is a contactless, usually short distance, wireless data transmission and reception technique for identification of objects. An RFID system consists of two components: the tag (also called transponder) and the reader (also called interrogator).
標(biāo)簽： Processing Digital Signal RFID for
上傳時(shí)間： 2020-06-08
上傳用戶(hù)：shancjb
隨著光通信的蓬勃發(fā)展，光纖通信技術(shù)廣泛應(yīng)用于電信、電力、廣播等領(lǐng)域，對(duì)整個(gè)信息產(chǎn)業(yè)產(chǎn)生了深遠(yuǎn)影響，光纖已成為當(dāng)前最有前景的傳輸媒介。與此同時(shí)，光纖測(cè)試技術(shù)在光纖生產(chǎn)、現(xiàn)場(chǎng)鋪設(shè)與后期維護(hù)等工程領(lǐng)域中得到廣泛應(yīng)用。光時(shí)域反射儀（Optical Time Domain Reflectometer），又稱(chēng)背向散射儀，是一種用于表征光纖鏈路物理特性的精密光學(xué)測(cè)試儀器，主要用于測(cè)試光纖鏈路長(zhǎng)度，精確定位斷點(diǎn)事件，計(jì)算光纖損耗，并提供與長(zhǎng)度有關(guān)的衰減細(xì)節(jié)。光纖鏈路中待測(cè)光纖的測(cè)量長(zhǎng)度范圍和測(cè)量精度，取決于OTDR的激光出纖功率和光脈寬。因此，需要設(shè)計(jì)合適的激光脈沖驅(qū)動(dòng)電源及配套的控制和探測(cè)系統(tǒng)，研究激光出纖功率和脈寬對(duì)測(cè)量長(zhǎng)度和測(cè)量精度的影響，從而獲得能滿(mǎn)足不同光纖鏈路測(cè)量需求的OTDR系統(tǒng)解決方案。文章在具體描述了光時(shí)域反射儀的工作機(jī)理以及影響其主要性能的關(guān)鍵參數(shù)的基礎(chǔ)上，提出以設(shè)計(jì)能提供大功率、窄脈沖電流信號(hào)的激光驅(qū)動(dòng)電源作為提高OTDR性能的主要手段。在掌握半導(dǎo)體激光驅(qū)動(dòng)原理的基礎(chǔ)上，經(jīng)過(guò)細(xì)致地比較與方案論證提出以 MOSFET作為激光脈沖驅(qū)動(dòng)電源的開(kāi)關(guān)器件，以能量?jī)?chǔ)存法作為窄脈沖產(chǎn)生機(jī)制的脈沖電源設(shè)計(jì)方案，設(shè)計(jì)實(shí)現(xiàn)基于FPGA的觸發(fā)脈沖信號(hào)，并通過(guò) Multisim對(duì)系統(tǒng)硬件電路仿真優(yōu)化，實(shí)現(xiàn)激光脈沖驅(qū)動(dòng)大功率、窄脈寬輸出。以雪崩二極管作為光電探測(cè)系統(tǒng)關(guān)鍵響應(yīng)轉(zhuǎn)換器件驗(yàn)證驅(qū)動(dòng)電源性能，并完成光纖測(cè)距。最終成功研制出一套基于納秒脈沖激光和對(duì)應(yīng)光電探測(cè)系統(tǒng)的OTDR系統(tǒng)，并進(jìn)行了實(shí)際測(cè)試測(cè)試和研究結(jié)果顯示：所研制的脈沖激光電源能輸出的最小脈寬為33n，最小輸出峰值電流為1A，且峰值電流及頻率大小可調(diào)。大電流窄脈寬驅(qū)動(dòng)電源信號(hào)輸出可極大地增強(qiáng)光時(shí)域反射儀的動(dòng)態(tài)范圍以及分辨率，探測(cè)器分時(shí)調(diào)控測(cè)量技術(shù)可以極大地提高系統(tǒng)的測(cè)量精度和信噪比。
標(biāo)簽： 激光 驅(qū)動(dòng) 電源 光電探測(cè)
上傳時(shí)間： 2022-03-11
上傳用戶(hù)：
光學(xué)相干層析（Optical Coherence Tomography，OCT成像方法具有高分辨率，非接觸，無(wú)損傷等優(yōu)點(diǎn)，應(yīng)用前景十分廣闊。但其實(shí)用性受到成像速度和穩(wěn)定性的限制，而成像速度和穩(wěn)定性主要是受到掃描方式的限制，采用頻域快掃描延遲線可以解決這些問(wèn)題。本裸題研究日的是為基于頻域快掃描延遲線的不同用途的光學(xué)相干層析成像系統(tǒng)中的信號(hào)探測(cè)電路設(shè)計(jì)提供理論依據(jù)和設(shè)計(jì)范例，為光學(xué)相干層析成像產(chǎn)業(yè)化提供參考依據(jù)。本文的研究?jī)?nèi)容主要包括以下幾個(gè)方面：（1）研制基于顎域快掃描延遲線參考臂的實(shí)用型OCT系統(tǒng)，在理論分析基礎(chǔ)上給出實(shí)際OCT系統(tǒng)中信號(hào)探測(cè)電路主要參數(shù)計(jì)算依據(jù)。（2）通過(guò)設(shè)計(jì)用于高散射介質(zhì)成像的光源中心波長(zhǎng)為1310nm的OCT系統(tǒng)信號(hào)探測(cè)電路，給出高分辨率，高信噪比OCT系統(tǒng)信號(hào)探測(cè)電路設(shè)計(jì)。（3）通過(guò)設(shè)計(jì)用于高吸收介質(zhì)成像的光源中心波長(zhǎng)為820mm的快速OCT系統(tǒng)信號(hào)探測(cè)電路，給出高成像速度OCT系統(tǒng)信號(hào)探測(cè)電路設(shè)計(jì)（4）對(duì)OCT系統(tǒng)進(jìn)行測(cè)試，對(duì)不同樣品成像，驗(yàn)證設(shè)計(jì)的信號(hào)探測(cè)電路能夠工作。本文中由理論分析得到采用頻域快掃描延遲線的OCT系統(tǒng)信號(hào)主要參數(shù)的計(jì)算公式為探測(cè)電路設(shè)計(jì)提供了理論依據(jù)：兩套OCT系統(tǒng)信號(hào)探測(cè)電路設(shè)計(jì)及實(shí)現(xiàn)不僅為OCT珠寶（珍珠）檢測(cè)和眼科檢測(cè)的實(shí)際應(yīng)用提供可行性，同時(shí)還對(duì)不同用途、不回性能側(cè)重點(diǎn)的OCT系統(tǒng)信號(hào)探測(cè)電路設(shè)計(jì)具有一定的參考價(jià)值。關(guān)鍵詞光學(xué)相干層析：快掃描延遲線：光電探測(cè)：電路設(shè)計(jì)
標(biāo)簽： 光學(xué) 光電探測(cè)系統(tǒng)
上傳時(shí)間： 2022-03-14
上傳用戶(hù)：shjgzh
本文首次設(shè)計(jì)并驗(yàn)證了基于macom三合一芯片設(shè)計(jì)的光模塊電路,該電路旨在提供一種滿(mǎn)足SFF-8472中規(guī)定的數(shù)字診斷功能的低成本SFP+模塊。電路采用激光器驅(qū)動(dòng)、限幅放大器、控制器以及時(shí)鐘恢復(fù)單元集成的單芯片,在保證高精度數(shù)字診斷功能基礎(chǔ)上,實(shí)現(xiàn)了低成本高可靠的特點(diǎn)。該電路在光接收接口組件與激光器驅(qū)動(dòng)和限幅放大器單元的限幅放大器部分之間接入濾波器來(lái)提高模塊的靈敏度及信號(hào)質(zhì)量。在控制器單元的數(shù)字電位器的引腳上采用外加電阻的方式避免出現(xiàn)上電不發(fā)光的故障問(wèn)題。該研究結(jié)果為下一代SFP-DD光模塊設(shè)計(jì)與開(kāi)發(fā)工作,奠定了一定的理論與實(shí)踐基礎(chǔ)。This paper designs and validates the Optical module circuit based on the MACOM Trinity chip for the first time.This circuit aims to provide a low-cost SFP module which meets the digital diagnosis function specified in SFF-8472.The circuit uses a single chip integrated with laser driver,limiting amplifier,controller and clock recovery unit.On the basis of ensuring high precision digital diagnosis function,it achieves the characteristics of low cost and high reliability.The circuit connects a filter between the Optical receiving interface module and the limiting amplifier part of the laser driver and limiting amplifier unit to improve the sensitivity and signal quality of the module.The pin of the digital potentiometer in the controller unit is equipped with an external resistance to avoid the problem of power failure.The research results lay a theoretical and practical foundation for Optical module design in high-speed data center.
上傳時(shí)間： 2022-04-03
上傳用戶(hù)：
1. 文檔概述1.1. 文檔目的本文檔描述對(duì)SPI-4.2 協(xié)議的理解，從淺入深地詳細(xì)講解規(guī)范。1.2. SPI-4.2 簡(jiǎn)介SPI-4.2 協(xié)議的全稱(chēng)為System Packet Interface ，可譯為“系統(tǒng)包接口” 。該協(xié)議由OIF（ Optical Internetwoking Forum ）創(chuàng)建，用于規(guī)定10Gbps 帶寬應(yīng)用下的物理層（ PHY）和鏈路層（ Link ）之間的接口標(biāo)準(zhǔn)。SPI-4.2 是一個(gè)支持多通道的包或信元傳輸?shù)慕涌冢饕獞?yīng)用于OC-192 ATM 或PoS 的帶寬匯聚、及10G 以太網(wǎng)應(yīng)用中。1.3. 參考資料1) SPI-4.2 協(xié)議的標(biāo)準(zhǔn)文檔。2) 中興公司對(duì)SPI-4.2 協(xié)議文檔的翻譯稿。2. SPI-4.2 協(xié)議2.1. SPI-4.2 系統(tǒng)參考模型圖 1 SPI-4.2 系統(tǒng)參考模型圖X:\ 學(xué)習(xí)筆記\SPI-4.2 協(xié)議詳解.doc - 1 - 創(chuàng)建時(shí)間： 2011-5-27 21:53:00田園風(fēng)光書(shū)屋NB0005 v1.1 SPI-4.2 協(xié)議詳解SPI-4.2 是一種物理層和鏈路層之間的支持多通道的數(shù)據(jù)包傳輸協(xié)議，其系統(tǒng)參考模型如上圖所示，從鏈路層至物理層的數(shù)據(jù)方向，稱(chēng)為“發(fā)送”方向，從物理層至鏈路層的數(shù)據(jù)方向，稱(chēng)為“接收”方向。在兩個(gè)方向上，都存在著流控機(jī)制。值得注意的是， SPI-4.2 是一種支持多通道（ Port）的傳輸協(xié)議。一個(gè)通道，指接收或發(fā)送方向上，相互傳輸數(shù)據(jù)的一對(duì)關(guān)聯(lián)的實(shí)體。有很多對(duì)關(guān)聯(lián)的實(shí)體，即很多個(gè)通道，都在同時(shí)傳輸數(shù)據(jù)，它們可復(fù)用SPI 總線。最多可支持256 個(gè)通道。例如OC-192 的192 個(gè)STS-1 通道，快速以太網(wǎng)中的100 個(gè)通道等， 各個(gè)通道的數(shù)據(jù)都可以相互獨(dú)立地復(fù)用在SPI總線上傳輸。
標(biāo)簽： SPI-4.2協(xié)議
上傳時(shí)間： 2022-06-19
上傳用戶(hù)：
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