Built-in Variable Fiber-optic Attenuators
Week News Abstract For Fiber Series in 10GTEK
The abstract is mainly about the optical communication related products,including: SFP,QSFP,FTTH,GPON,EPON,SFPPLC,PTN,ODN,Sfp Transceiver,Optic Transceiver,Optical module,Optical devices,optical communications,Optical transceiver module,Etc.
Built-in Variable Fiber-optic Attenuators
Built-in variable optical attenuators may be either manually or electrically controlled.A manual device is useful for one-time set up of a system, and is a near-equivalent to a fixed attenuator, and may be referred to as an "adjustable attenuator". In contrast, an electrically controlled attenuator can provide adaptive power optimization.Attributes of merit for electrically controlled devices, include speed of response and avoiding degradation of the transmitted signal. Dynamic range is usually quite restricted, and power feedback may mean that long term stability is a relatively minor issue. Speed of response is a particularly major issue in dynamically reconfigurable systems, where a delay of one millionth of a second can result in the loss of large amounts of transmitted data. Typical technologies employed for high speed response include LCD, or Lithium niobate devices.There is a class of built-in attenuators that is technically indistinguishable from test attenuators, except they are packaged for rack mounting, and have no test display.[KST_Fiber Optic Cable Manufacturer,in Shenzhen,Guangdong]
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Fundamentals of Rayleigh Scatter Based Fibre Optic Sensing
In Rayleigh scatter based distributed optical fiber cable sensing, a coherent laser pulse is sent along an optic fiber cable, and scattering sites within the fiber cause the fiber to act as a distributed interferometer with a gauge length approximately equal to the pulse length. The intensity of the reflected light is measured as a function of time after transmission of the laser pulse. When the pulse has had time to travel the full length of the fiber and back, the next laser pulse can be sent along the fibre. Changes in the reflected intensity of successive pulses from the same region of fibre are caused by changes in the optical path length of that section of fiber. This type of system is very sensitive to both strain and temperature variations of the fiber and measurements can be made simultaneously at all sections of the optical fiber cable.
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Comparison of the Optical Fiber Communication with the Electric Transmission
The choice between optical fiber cable and electrical (or copper) transmission for a particular system is made based on a number of trade-offs. Optical fiber is generally chosen for systems requiring higher bandwidth or spanning longer distances than electrical cabling can accommodate.The main benefits of fiber are its exceptionally low loss (allowing long distances between amplifiers/repeaters), its absence of ground currents and other parasite signal and power issues common to long parallel electric conductor runs (due to its reliance on light rather than electricity for transmission, and the dielectric nature of fiber optic), and its inherently high data-carrying capacity. Thousands of electrical links would be required to replace a single high bandwidth fiber cable. Another benefit of fibers is that even when run alongside each other for long distances, fiber cables experience effectively no crosstalk, in contrast to some types of electrical transmission lines. Fiber can be installed in areas with high electromagnetic interference (EMI), such as alongside utility lines, power lines, and railroad tracks. Nonmetallic all-dielectric cables are also ideal for areas of high lightning-strike incidence.For comparison, while single-line, voice-grade copper systems longer than a couple of kilometers require in-line signal repeaters for satisfactory performance; it is not unusual for optical systems to go over 100 kilometers (62 mi), with no active or passive processing. Single-mode fiber cables are commonly available in 12 km lengths, minimizing the number of splices required over a long cable run. Multi-mode fiber is available in lengths up to 4 km, although industrial standards only mandate 2 km unbroken runs.In short distance and relatively low bandwidth applications, electrical transmission is often preferred because of its1 Lower material cost, where large quantities are not required2 Lower cost of transmitters and receivers?3 Capability to carry electrical power as well as signals (in specially designed cables)4 Ease of operating transducers in linear mode.Optical fibers are more difficult and expensive to splice than electrical conductors. And at higher powers, optical fibers are susceptible to fiber fuse, resulting in catastrophic destruction of the fiber core and damage to transmission components.Because of these benefits of electrical transmission, optical communication is not common in short box-to-box, backplane, or chip-to-chip applications; however, optical systems on those scales have been demonstrated in the laboratory.In certain situations fiber may be used even for short distance or low bandwidth applications, due to other important features:1 Immunity to electromagnetic interference, including nuclear electromagnetic pulses (although fiber can be damaged by alpha and beta radiation).2 High electrical resistance, making it safe to use near high-voltage equipment or between areas with different earth potentials.3 Lighter weight—important, for example, in aircraft.4 No sparks—important in flammable or explosive gas environments.5 Not electromagnetically radiating, and difficult to tap without disrupting the signal—important in high-security environments.6 Much smaller cable size—important where pathway is limited, such as networking an existing building, where smaller channels can be drilled and space can be saved in existing cable ducts and trays.7 Resistance to corrosion due to non-metallic transmission medium?Optical fiber cables can be installed in buildings with the same equipment that is used to install copper and coaxial cables, with some modifications due to the small size and limited pull tension and bend radius of optical cables. Optical cables can typically be installed in duct systems in spans of 6000 meters or more depending on the duct's condition, layout of the duct system, and installation technique. Longer cables can be coiled at an intermediate point and pulled farther into the duct system as necessary.
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The above information is edited by 10GTEK.
10GTEK TRANSCEIVERS CO., LTD (Hereinafter refered to as 10GTEK) is specialized in developing and manufacturing Fiber Optical Transceivers and High Performance Cables which are wildly applied in Datacom, Telecom and CATV, providing customers with top quality and cost effective products. Our High Speed Cables cover Passive SFP+ Cable, Active SFP+ Cable, QSFP+ cables, MiniSAS (SFF-8088) Cables, CX4 Cables, Harness cables, Breakout Cables, Patchcords. We also manufacture Fiber Optic Transceivers like 10G XFP, 10G SFP+, SFP DWDM/ CWDM, GBIC, etc. The prompt response and excellent customer support contribute to clients‘ full satisfaction.Today, 10GTEK has been growing fast in the optical field for its unique and competitve excellence which has got a high attention from datacom and telecom.
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