Glossary

A material

A technique or method for measuring the optical attenuation or bandwidth in a fiber by measuring first from the end and then from a shorter length and comparing the difference. Usually one is at the full length of the fiberoptic cable and the other is within a few meters of the input.

For a single-mode fiber, the wavelength above which the operation switches from multimode to single-mode propagation. This is the longest wavelength at which a single-mode fiber can transmit two modes. At shorter wavelengths the fiber fails to function as a single-mode fiber.

The count of oscillations in a wave. One cycle per second equals a hertz.

An error-checking technique used to ensure the accuracy of transmitting digital code over a communications channel after the data is transmitted. Transmitted messages are divided into predetermined lengths that are divided by a fixed divisor. The result of this calculation is appended onto the message and sent with it. At the receiving end, the computer performs this calculation again. If the value that arrived with the data does not match the value the receiver calculated, an error has occurred during transmission.