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Sharp bends stress optic fibers and can cause losses. If a received signal is too strong a temporary fix is to wrap the cable around a pencil until the desired level of attenuation is achieved. [1] However, such arrangements are unreliable, since the stressed fiber tends to break over time.
Attenuation is linearly dependent on the medium length and attenuation coefficient, as well as – approximately – the frequency of the incident ultrasound beam for biological tissue (while for simpler media, such as air, the relationship is quadratic). Attenuation coefficients vary widely for different media.
Specialized cables are used for long-distance subsea data transmission, e.g. transatlantic communications cable. New (2011–2013) cables operated by commercial enterprises (Emerald Atlantis, Hibernia Atlantic) typically have four strands of fiber and signals cross the Atlantic (NYC-London) in 60–70 ms. The cost of each such cable was about ...
In the professional literature, the effect is often named Radiation Induced Attenuation (RIA), or Radiation-induced darkening. The loss of power or 'darkening' occurs because the chemical bonds forming the optical fiber core are disrupted by the impinging high energy resulting in the appearance of new electronic transition states giving rise to additional absorption in the wavelength regions ...
The optical power budget (also fiber-optic link budget and loss budget) in a fiber-optic communication link is the allocation of available optical power (launched into a given fiber by a given source) among various loss-producing mechanisms such as launch coupling loss, fiber attenuation, splice losses, and connector losses, in order to ensure that adequate signal strength (optical power) is ...
Attenuation over a cable run is significantly increased by the inclusion of connectors and splices. When computing the acceptable attenuation (loss budget) between a transmitter and a receiver one includes: dB loss due to the type and length of fiber optic cable, dB loss introduced by connectors, and; dB loss introduced by splices.
Because damage to the cable can cause reflections, an instrument called an electrical time-domain reflectometer (ETDR; for electrical cables) or an optical time-domain reflectometer (OTDR; for optical cables) can be used to locate the damaged part of a cable. These instruments work by sending a short pulsed signal into the cable and measuring ...
The optical pulse is attenuated as it propagates along the fiber. For a single mode fiber operating at 1550 nm, a typical attenuation is 0.2 dB/km. [1] Since the light must make a double pass along each section of fiber, this means each 1 km causes a total loss of 0.4 dB. The maximum range of the system occurs when the amplitude of the ...