Learning Center

FIBER-OPTIC CABLE

July 16, 2014

CABLE CHARACTERISTICS Fiber-optic cable is jacketed glass fiber. In order to be usable in fiber-optic systems, the somewhat fragile optical fibers are packaged inside cables for strength and protection against breakage, as well as against such environmental hazards as moisture, abrasion, and high temperatures. Packaging of fiber in cable also protects the fibers from bending at too sharp an angle, which could result in breakage and a consequent loss of signal. Multiconductor cable is available for all designs and can have as many as 144 fibers per cable. It is noteworthy that a cable containing 144 fibers can be as

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FIBER-OPTIC BASICS

July 15, 2014

BASIC FIBER CONSTRUCTION Optical fiber consists of a thin strand (or core) of optically pure glass surrounded by another layer of less pure glass (the cladding). The inner core is the light-carrying part. The surrounding cladding provides the difference in refractive index that allows total internal reflection of light through the core. The index of the cladding is less than 1 percent lower than that of the core. Most fibers have an additional coating around the cladding. This coating, usually one or more layers of polymer, protects the core and cladding from shocks that might affect their optical or physical

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INTRODUCTION TO FIBER

July 14, 2014

HISTORY The use of light for the transmission of information is far from a new idea. Paul Revere’s lanterns were used to signal the approach of the British. And it was Alexander Graham Bell’s experiments over a century ago that led to his development of the photophone, a device that carried speech from one point to another by means of vibrating mirrors and a beam of sunlight. Although never a commercial success, it nevertheless demonstrated the feasibility of lightwave communications. However the technique was shunted aside and virtually forgotten for almost another hundred years. It probably would have remained in

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Preparing for 100-GbE in the data center

July 11, 2014

With the continued requirement for expansion and growth in the data center, cabling infrastructures must provide reliability, manageability, and flexibility. Deployment of an optical connectivity solution allows for an infrastructure that meets these requirements for current applications and data rates. Scalability is an additional key factor when choosing the type of optical connectivity. Scalability refers not only to the physical expansion of the data center with respect to additional servers, switches, or storage devices, but also to the infrastructure to support a migration path for increasing data rates. As technology evolves and standards are completed to define data rates, such

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Buried Cable Installation Best Practices (2)

July 8, 2014

5.0 PLOWING VERSUS TRENCHING 5.01 In general, the most desirable and economical method of cable placement in open or rural areas is plowing. Here there will be fewer obstacles to impede the progress of the plowing equipment. Advantages of Plowing: Speed of installation in open areas Less ground disturbance than may be caused by trenching Disadvantages of Plowing: Large size and high cost of equipment Requires skilled equipment operators, quality supervision, and equipment in good condition Can not be used for all soil and terrain conditions Possibility of damaging cables or underground utilities 5.02 In urban or suburban areas where

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Buried Cable Installation Best Practices (1)

July 7, 2014

1.0 GENERAL 1.01 This best practices procedure provides general information for the installation of fiber optic cables in direct buried applications. The methods described are intended for guideline use only, as it is impossible to cover all the various conditions that may arise during an installation. Individual company practices for placing fiber optic cable should supersede any conflicting instructions in this document when they do not exceed the cable’s optical and mechanical performance specifications. 1.02 Placement methods for direct buried fiber optic cable are essentially the same as those used for placing direct buried copper cable. However it must be

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Fiber Optic Cable Installation Guidelines

June 30, 2014

Safety Precautions • When installed on a live system, invisible laser radiation may be present. Do not stare into connector end face or view directly with optical instruments. • Wear safety glasses when working with optical fiber. • Dispose of all scrap fibers to avoid getting fiber slivers. 1 Scope The following guidelines are intended as a general overview of important issues related to the installation of fiber optic cable. 2 Installation Specifications For a proper cable installation, it is important to understand the cable specifications. The two most important specifications are tensile loading and bend radius. It is very

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Optics for Fiber Laser Applications

June 27, 2014

Fiber lasers have found a processing and research niche where Nd:YAG lasers are too expensive or have beam properties which are undesirable (e.g. large M2 values). Users of fiber lasers may be concerned with the interchangeability of their existing supply of optical components or how to specify new optics. This article addresses such areas of concern and highlights which characteristics should be specified particularly carefully. Fiber lasers are gaining ground in a variety of applications such as drilling, welding, foil cutting, laser marking, and precise micro-machining. Research scientists are also finding them very useful as sources because of their small

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Photonics Spectra CCD vs CMOS: Facts and Fiction

June 26, 2014

Much has been made in the past five years of the potential for CMOS imagers and of the impending demise of the incumbent image-sensing technology,CCDs. Strong claims by the proponents of a resurgent CMOS technology have been countered by equally forceful claims by CCD defenders. In a pattern typical of battling technologies (both with significant merits but also lacking maturity in some regards), users have become leery of performance representations made by both camps. Overly aggressive promotion of both technologies has led to considerable fear, uncertainty and doubt. Imager basics For the foreseeable future, there will be a significant role

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MECHANICAL FIBER POLISHING (2)

June 24, 2014

POLISHING TECHNIQUES Critical to proper polishing is the applied process–the technique–that results in meeting the various specifications. Early connectors were all produced with flat end-faces, which were specified to be close (the linear tolerance on the SMA, for example, being 8 microns), but too specifically avoid actual contact. As Polishing evolved the PC (Physical Contact) concept was developed–spherical end-faces, with the fibers making actual physical contact–The PC finish resulted in much improved performance because air-gap was eliminated which allowed increased light wave transmission. The early PC connectors, preceding development of the now common pre-radiused ferrules, required spherical forming of their

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