NLS-Glossary

Dispersion in fiber optics is the spread in time, known as temporal broadening, of an infinitesimally thin optical pulse as it propagates along the fiber.

The temporal broadening is due to the different propagation characteristics of different wavelength components of light that are coupled into the fiber and propagate along the guide. Due to the dispersion effect there is an upper limit for the rate at which we can transmit light pulses along a fiber.

When goods are shipped to a distribution center, the container marking specifications are usually different from those required when shipping directly to a store.                        

Diverging waves have wavevectors, vectors that are normal to the wavefront, that are not parallel. The vector that is normal to a wavefront surface at a point such as P represents the direction of wave propagation (k) at that point P.

Clearly, the propagation vectors everywhere are all parallel and the plane wave propagates without the wave diverging; the plane wave has no divergence. The amplitude of the planar wave does not depend on the distance from a reference point, and it is the same at all points on a given plane perpendicular to k, i.e. independent of x and y. Moreover, as these planes extend to infinity, there is infinite energy in the plane-wave. A plane wave is an idealization that is useful in analyzing many wave phenomena. In reality, however, the electric field in a plane at right angles to k does not extend to infinity since the light beam would have a finite cross sectional area and finite power. (We would need an infinitely large electromagnetic source with infinite power to generate a perfect plane wave.)

A system of impact printing where individual dots are printed by tiny wires striking the supply through an inked ribbon.                                                                                              

The size of the printed dot on a substrate in a matrix or line to form characters. Minimum dot size is determined by the size of the thermal element of the print head being used by the thermal printer. Dot size determines the X dimension. The X dimension is always a simple multiple of the dot size.

The diameter of the beam of light projected by the scanner used to read a bar code symbol. The scanner dot size should be no larger than the X dimension of the bar code symbol.