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.
標簽： Propagation Light Media Gain in
上傳時間： 2020-05-27
上傳用戶：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.
標簽： Communications Essentials OPTICAL
上傳時間： 2020-05-31
上傳用戶：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.
標簽： Communication Visible Light
上傳時間： 2020-06-01
上傳用戶：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).
標簽： Multiplexing Wavelength Division
上傳時間： 2020-06-01
上傳用戶：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.
標簽： Multiusers Detection Wireless Networks
上傳時間： 2020-06-01
上傳用戶：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).
標簽： Processing Digital Signal RFID for
上傳時間： 2020-06-08
上傳用戶：shancjb
隨著光通信的蓬勃發(fā)展，光纖通信技術廣泛應用于電信、電力、廣播等領域，對整個信息產業(yè)產生了深遠影響，光纖已成為當前最有前景的傳輸媒介。與此同時，光纖測試技術在光纖生產、現(xiàn)場鋪設與后期維護等工程領域中得到廣泛應用。光時域反射儀（OPTICAL Time Domain Reflectometer），又稱背向散射儀，是一種用于表征光纖鏈路物理特性的精密光學測試儀器，主要用于測試光纖鏈路長度，精確定位斷點事件，計算光纖損耗，并提供與長度有關的衰減細節(jié)。光纖鏈路中待測光纖的測量長度范圍和測量精度，取決于OTDR的激光出纖功率和光脈寬。因此，需要設計合適的激光脈沖驅動電源及配套的控制和探測系統(tǒng)，研究激光出纖功率和脈寬對測量長度和測量精度的影響，從而獲得能滿足不同光纖鏈路測量需求的OTDR系統(tǒng)解決方案。文章在具體描述了光時域反射儀的工作機理以及影響其主要性能的關鍵參數(shù)的基礎上，提出以設計能提供大功率、窄脈沖電流信號的激光驅動電源作為提高OTDR性能的主要手段。在掌握半導體激光驅動原理的基礎上，經過細致地比較與方案論證提出以 MOSFET作為激光脈沖驅動電源的開關器件，以能量儲存法作為窄脈沖產生機制的脈沖電源設計方案，設計實現(xiàn)基于FPGA的觸發(fā)脈沖信號，并通過 Multisim對系統(tǒng)硬件電路仿真優(yōu)化，實現(xiàn)激光脈沖驅動大功率、窄脈寬輸出。以雪崩二極管作為光電探測系統(tǒng)關鍵響應轉換器件驗證驅動電源性能，并完成光纖測距。最終成功研制出一套基于納秒脈沖激光和對應光電探測系統(tǒng)的OTDR系統(tǒng)，并進行了實際測試測試和研究結果顯示：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。大電流窄脈寬驅動電源信號輸出可極大地增強光時域反射儀的動態(tài)范圍以及分辨率，探測器分時調控測量技術可以極大地提高系統(tǒng)的測量精度和信噪比。
上傳時間： 2022-03-11
上傳用戶：
光學相干層析（OPTICAL Coherence Tomography，OCT成像方法具有高分辨率，非接觸，無損傷等優(yōu)點，應用前景十分廣闊。但其實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相干層析成像系統(tǒng)中的信號探測電路設計提供理論依據和設計范例，為光學相干層析成像產業(yè)化提供參考依據。本文的研究內容主要包括以下幾個方面：（1）研制基于顎域快掃描延遲線參考臂的實用型OCT系統(tǒng)，在理論分析基礎上給出實際OCT系統(tǒng)中信號探測電路主要參數(shù)計算依據。（2）通過設計用于高散射介質成像的光源中心波長為1310nm的OCT系統(tǒng)信號探測電路，給出高分辨率，高信噪比OCT系統(tǒng)信號探測電路設計。（3）通過設計用于高吸收介質成像的光源中心波長為820mm的快速OCT系統(tǒng)信號探測電路，給出高成像速度OCT系統(tǒng)信號探測電路設計（4）對OCT系統(tǒng)進行測試，對不同樣品成像，驗證設計的信號探測電路能夠工作。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)信號主要參數(shù)的計算公式為探測電路設計提供了理論依據：兩套OCT系統(tǒng)信號探測電路設計及實現(xiàn)不僅為OCT珠寶（珍珠）檢測和眼科檢測的實際應用提供可行性，同時還對不同用途、不回性能側重點的OCT系統(tǒng)信號探測電路設計具有一定的參考價值。關鍵詞光學相干層析：快掃描延遲線：光電探測：電路設計
標簽： 光學 光電探測系統(tǒng)
上傳時間： 2022-03-14
上傳用戶：shjgzh
本文首次設計并驗證了基于macom三合一芯片設計的光模塊電路,該電路旨在提供一種滿足SFF-8472中規(guī)定的數(shù)字診斷功能的低成本SFP+模塊。電路采用激光器驅動、限幅放大器、控制器以及時鐘恢復單元集成的單芯片,在保證高精度數(shù)字診斷功能基礎上,實現(xiàn)了低成本高可靠的特點。該電路在光接收接口組件與激光器驅動和限幅放大器單元的限幅放大器部分之間接入濾波器來提高模塊的靈敏度及信號質量。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)光的故障問題。該研究結果為下一代SFP-DD光模塊設計與開發(fā)工作,奠定了一定的理論與實踐基礎。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.
上傳時間： 2022-04-03
上傳用戶：
1. 文檔概述1.1. 文檔目的本文檔描述對SPI-4.2 協(xié)議的理解，從淺入深地詳細講解規(guī)范。1.2. SPI-4.2 簡介SPI-4.2 協(xié)議的全稱為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 帶寬應用下的物理層（ PHY）和鏈路層（ Link ）之間的接口標準。SPI-4.2 是一個支持多通道的包或信元傳輸?shù)慕涌冢饕獞糜贠C-192 ATM 或PoS 的帶寬匯聚、及10G 以太網應用中。1.3. 參考資料1) SPI-4.2 協(xié)議的標準文檔。2) 中興公司對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:\ 學習筆記\SPI-4.2 協(xié)議詳解.doc - 1 - 創(chuàng)建時間： 2011-5-27 21:53:00田園風光書屋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)據方向，稱為“發(fā)送”方向，從物理層至鏈路層的數(shù)據方向，稱為“接收”方向。在兩個方向上，都存在著流控機制。值得注意的是， SPI-4.2 是一種支持多通道（ Port）的傳輸協(xié)議。一個通道，指接收或發(fā)送方向上，相互傳輸數(shù)據的一對關聯(lián)的實體。有很多對關聯(lián)的實體，即很多個通道，都在同時傳輸數(shù)據，它們可復用SPI 總線。最多可支持256 個通道。例如OC-192 的192 個STS-1 通道，快速以太網中的100 個通道等， 各個通道的數(shù)據都可以相互獨立地復用在SPI總線上傳輸。
標簽： SPI-4.2協(xié)議
上傳時間： 2022-06-19
上傳用戶：
