Glossary

The total difference in travel time between the two polarization states of light traveling through an optical fiber. This time is usually measured in picoseconds, and can differ depending on specific conditions within an optical fiber and the polarization state of the light passing through it.

The test method used to determine the variation in arrival time of modes in a pulse of light in an optical fiber (typically for multimode fiber).

A variation in attenuation in and among modes carried in an optical fiber.

The deviation of a wave front from the path predicted by geometric optics when a wave front is restricted by an edge or an opening of an object. Diffraction is most significant when the aperture is equal to the order of the wavelength.

An array of fine, parallel, equally spaced reflecting or transmitting lines that mutually enhance the effects of diffraction to concentrate the diffracted light in a few directions determined by the spacing of the lines and by the wavelength of the light.

It enables the use of infrared optical emissions without the need for line-of-sight between the transmitting and receiving communication entities.

Refers to transmission, processing, and storage of data by representing the data in binary values (two states: on or off). On is represented by the number 1 and off by the number 0. Data transmitted or stored with digital technology is expressed as a string of 0s and 1s. Digital signals are used to communicate information between computers or computer-controlled hardware.

A carrier system used for pair gain and providing multiple next generation digital services over traditional copper loop in local loop applications.

A representation of a digital signal carrier in the TDM hierarchy. Each DS level is made up of multiple 64Kbps channels (generally thought of as the equivalent to a voice channel) known as DS-0 circuits. A DS-1 circuit (1.544Mbps) is made up of 24 individual DS-0 circuits. DS rates are specified by ANSI, CEPT, and the ITU.

A piece of equipment that serves as a connection point for a particular digital signal rate. Each DSX equipment piece is rated for the DS circuit it services

A device that manipulates or processes data that has been converted from analog to digital form.

A technology for delivering high bandwidth to homes and businesses using standard telephone lines. Though many experts believed that standard copper phone cabling would never be able to support high data rates, local phone companies are deploying equipment that is capable of supporting up to theoretical rates of 8.4Mbps. Typical throughput downstream (from the provider to the customer) are rates from 256Kbps to 1.544Mbps. DSL lines are capable of supporting voice and data simultaneously. There are many types, including HDSL (high bitrate DSL) and VDSL (very high bit-rate DSL).

DIN - (German standards) Abbreviation for Deutsche Industry Norm

A device that allows a current to move in only one direction. Some examples of diodes are light-emitting diodes (LEDs), laser diodes, and photodiodes.

A combiner unit designed to combine 2G and 3G Tx and Rx signals onto a common feeder /antenna system