博文

目前显示的是 九月, 2015的博文

Hybrid Fiber Coax (HFC) Access Network

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As cable and telecommunication operators are striving to introduce new services to meet the surge in data demand, they must find a plan that evolves their current networks and maximize their full capacity. HFC, as an upgraded community antenna television (CATV) network, might be a great news for them. The purpose of this article is to present a brief introduction to HFC network. In order to have a better understanding of HFC, let’s first get familiar with CATV network. CATV refers to a system of transmitting television signals to subscribers, using radio frequency (RF) signals transmitted through coaxial cable. But 1980s witnessed a breakthrough in cable television network that CATV can be transmitted through optical fiber. Definition of HFC
HFC refers to a broadband telecommunication network that combines optical fiber and coaxial cable, which has been utilized globally by cable television operators since the early 1990s. HFC is also called the 2nd generation of CATV systems that use…

Mechanical Splicing vs. Fusion Splicing

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Knowledge of splicing technology is essential for companies or fiber optic technicians involved in telecommunication field. To put it simply, fiber optic splicing involves joining two fibers together under the influence of heat. There are two preferred types of splicing methods: fusion splicing and mechanical splicing. Understanding the pros and cons of each splicing method is extremely important when making an educated decision on which splicing method to use. If you are beginning to splice fiber, you might want to have a look at this article. I bet you will get your answer at the end of it. Mechanical Splicing
Mechanical splicing is simply aligned and designed to hold in place by a self-contained assembly. Two fibers are not permanently joined, just precisely held together enabling light to pass from one fiber into the other. (Typical loss: 0.3 dB) Fusion Splicing
In fusion splicing, a machine is used to precisely align the two fiber ends together, then the glass ends are "fused…

EPON vs. GPON – A Practical Comparison

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Ethernet passive optical network (EPON) and Gigabit passive optical network (GPON), just like the super heroes in the Hollywood movies, which lead the tide of broadband access and optical telecom application, becoming the new hot spot. As fiber access is poised for strong growth, subscribers may wonder how to choose between the two main PON standards: EPON and GPON. The following passage will make a comparison between them. EPON vs. GPON Standard
EPON, based on Ethernet technology, is compliant with the IEEE 802.3ah (mid-2004) Ethernet in the First Mile standard that is now merged into the IEEE Standard 802.3-2005. It is a solution for the "first mile" optical access network. While GPON, or Gigabit PON, is expected to prevail as a leading optical access technology and to eliminate the bandwidth bottleneck in the last mile. Its requirements were set force by the Full Service Access Network (FASN) group, which was later adopted by ITU-T as the G.984.x standards. EPON vs. GPON D…

Next-Generation PON Evolution

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Optical access is gaining more interest as the demand for higher and higher bandwidth is getting stronger. Yet the limitation in transport distance and cost has been slowing down penetration of the optical access. Recently a number of alternative transport concepts have been developed to tackle the cost problem as well as the technical ones, the passive optical network(PON) techniques are largely anticipated to be the most economical solutions. What Is Passive Optical Network?
A passive optical network features a point-to-multipoint (P2MP) architecture to provide broadband access. It is a telecommunications network that uses single, shared optical fiber in which inexpensive optical splitters to divide the single fiber into separate strands feeding individual subscribers. PON is called "passive", because, other than at the Central Office (CO) and subscriber endpoints, there are no active electronics within the access network. In passive optical system, a single fiber from a c…

Fiber Patch Cable–How to Make the Right Choice

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Learning how to make a proper selection of fiber optic cable for specific users is growing even important as fiber optic systems become the transmission medium of communications and aircraft applications. The following questions and answers will guide readers through the choices that must be made in selecting fiber optic cable for high-reliability applications. How to Choose Between Multimode and Single-mode Fiber Cable?
There are two main types of fiber to choose from — multimode and single-mode. The fiber type is predominantly determined by the data rate of the system, transmission distance and cost. Multimode is typically recommended for applications involving shorter distance. If your application only requires transmitting a distance of 550 m or less, multimode fiber optic cables are recommended, which is also a lower cost solution and is often preferred by designers. However, if you need to support longer distances and achieve unlimited bandwidth, single-mode fiber is the best so…

CWDM SFP vs DWDM SFP – Which One Suits You Better?

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SFP (Small Form-Factor Pluggable) is designed to meet Multi-Source Agreement (MSA) standards to ensure network equipment compatibility. Recently wavelength-division multiplexing (WDM) technology is warmly welcomed by internet users all around the world. It is a technology that multiplexes a number of optical carrier signals at different wavelengths of laser light over a single optical fiber. By using WDM technology, SFP module can have different wavelengths assigned to them. The following passage will be focused on the brief descriptions of CWDM SFP and DWDM SFP. Overview of CWDM SFP
CWDM SFP is a kind of optical transceiver that utilizes in CWDM technology. Similarly with traditional SFP module, CWDM SFP is a hot-swappable input/output device that plugs into a SFP port or slot of a switch or router, linking the port with the fiber-optic network. CWDM SFP transceiver modules make use of the SFP interface for connecting the equipment and use dual LC/PC fiber connector interface for con…

The Role of EDFA in Optical Fiber Communication

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Long-haul telecommunication technology has undergone a tremendous revolution since the introduction of fiber optics technology. We can’t deny that its tremendous capacity for carrying information in digital form is revolutionizing the way people live and work today. And the most recent element adding to the success of these systems is optical amplifier. The purpose of this passage is to provide an introduction to EDFA technology. EDFA Overview
EDFA, short for Erbium Doped Fiber Amplifier, is an optical amplifier, of which the core is doped with the rare-earth element Erbium. By using the Erbium ions to higher energy levels, we can achieve amplification of signals at 1550 nm and allow high bit-rate transmission over long distance. EDFA provides a new life to optical fiber transmission as it efficiently makes up the signal attenuation during the long-haul transmission. A sample of EDFA Optical Amplifier is shown below.
Basic Principle of EDFA
At the heart of EDFA technology is the Erbium…

General Guide to OTDR

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Learning how to operate an OTDR properly is a very important skill for technicians in companies management and maintenance of fiber optic networks. The following passage contains clearer descriptions of OTDR to aid the users in understanding the basic principles of OTDR testing. Introduction of OTDR
An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber. It functions by launching pulses of light into the optical fiber and measuring the intensity of reflections created by the faults, splices, and bends. And it can also identify the exact location of the fault by measuring the round trip time from the launch to the detection of the reflected returning pulse. By analyzing the OTDR trace, we can get a full report of losses as well as reflective events (connectors and mechanical splices) tied to the distance or the geographical information of an optical fiber link. And the basic function of OTDR is to verify splice loss, measure le…