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Insertion Loss

Definition: power losses due to insertion of a device

German: Einfügedämpfung

Categories: general optics, fiber optics and waveguides

Units: %, dB

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If an optical device is inserted into a setup, some of the optical power may be lost in the device or at optical interfaces. Some examples:

The insertion loss (or attenuation) is usually specified in decibels, calculated as 10 times the logarithm of base 10 of the ratio of output and input powers. For fiber connectors, for example, it is often of the order of 0.5 dB. High-quality fusion splices may reach values like 0.02 dB.

For high-power devices, a high insertion loss is often unwanted not only due to the power loss but also because of possibly strong heating effects resulting from absorbed light.

A convenient method for measuring insertion loss is optical time-domain reflectometry. With that, the insertion loss of multiple optical elements along a fiber can be measured separately.

See also: fiber connectors, fusion splicing of fibers, decibel, return loss, optical time-domain reflectometers
and other articles in the categories general optics, fiber optics and waveguides


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