Photonics Dictionary

A waveguide is a physical structure or device that is designed to confine and guide electromagnetic waves, such as radio waves, microwaves, or light waves. It is commonly used in communication...

For each mode in an optical waveguide, the term used to describe the process by which an electromagnetic signal is distorted by virtue of the dependence of the phase and group velocities on...

Gas laser in which the tube acts as a channel for the laser beam.

A device that consists of two types of mode converters, one of which must be magnetic. It is nonreciprocal because the coupling constants of the two mode converters have a different phase relation...

Scattering (other than material scattering) that is attributable to variations of geometry and index profile of the waveguide.

A waveguide made up of a dielectric material, such as plastic or mica, in a cylindrical form, through which the waves travel.

An infrared-transmitting optical fiber with a hollow core; it can be square, round or rectangular in cross section. Capable of carrying high laser power but subject to high bending losses.

An optical waveguide that will allow more than one bound mode to propagate.

Any structure having the ability to guide the flow of radiant energy along a path parallel to its axis and to contain the energy within or adjacent to its surface.

A configuration or device mounted at the end of a fiber or cable that is intended to prevent reflection.

A pair of waveguides with axes normal to the plane and that guide uniform cylindrical waves.

An optical waveguide in which only the lowest order bound mode, which may consist of a pair of orthogonally polarized fields, can propagate at the wavelength of interest.

A waveguide with a rectangular cross section that is composed entirely of dielectric materials.

A waveguide having a characteristic that is altered continuously with the distance traveled, relative to the axis of its path.

A transparent dielectric film, bounded by material of a lower index of refraction, capable of guiding light.

A waveguide that has a core with a lower refractive index than the refractive index of the cladding. This structure can limit the power of the transmitted beam by removing unwanted radiation, for...

Angular deviation from the optimum alignment of source to optical waveguide, waveguide to waveguide, or waveguide to detector, resulting in a loss of optical power.

The propagation constant evaluated along the axis of a waveguide, that is, in the direction of transmission. Also called axial propagation wave number.

The central hole running the full length of a laser capillary tube, in which electrical discharge and laser action take place. Also a similar hole in a hollow waveguide or a microchannel plate.

A broadband filter is an electronic or electromagnetic device designed to pass a range of frequencies or signals within a specified bandwidth while attenuating or rejecting signals outside of that...

1. In color development, the chemical that combines with certain by-products of the development procedure to form a dye. 2. Device for distributing optical power among two or more ports. 3. Device...

Operation in which the dispersion of a pulse limits the distance between repeaters in optical systems. Waveguide and material dispersion can make recognition of a pulse impossible.

A method of fabricating an optical waveguide by melting the core and clad glasses in two suitably joined concentric crucibles and then drawing a fiber from the combined melted glass.

Propagation of electromagnetic waves through the Earth's atmosphere in a path that conforms to the curvature of the Earth due to atmospheric thermal inversion. Regions of the atmosphere act as a...

In a waveguide, a change in direction of the axis without deviating from the plane of polarization.

An edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the semiconductor chip rather than from the surface. Edge-emitting LEDs are...

An electro-optic modulator (EOM) is a device used to modulate the amplitude, phase, or polarization of light waves using an external electrical signal. Electro-optic modulation is a fundamental...

The use of an electric field or signal to couple a lightwave from one dielectric waveguide into another dielectric waveguide.

End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the electromagnetic waves are directed primarily along the axis or direction...

The length of optical waveguide needed to attain equilibrium mode distribution for a specified excitation condition.

The condition in a multimode optical waveguide in which the relative power distribution among the propagating modes is independent of length.

The diffraction pattern of a source such as a light-emitting diode, injection laser diode or the output end of an optical waveguide observed at an infinite distance from the source.

A laser with output over a wide range of wavelengths spanning the far-infrared region of the spectrum (30 to 1000 µm); typically, it consists of a metal or dielectric waveguide one to two...

A waveguide or coaxial cable that transmits a signal from an antenna to a receiver or from a transmitter to an antenna.

A fiber-coupled LED (light-emitting diode) refers to an LED device that is optically coupled to an optical fiber for the purpose of efficient light transmission. In this configuration, the LED serves...

The lowest order mode of a waveguide. In fibers, the mode designated LP01 or HE11.

In an optical waveguide, a mode whose field decays monotonically in the transverse direction everywhere external to the core and which does not lose power to radiation. Also called bound mode.

In an optical waveguide, a ray that is completely confined to the core.

With respect to waveguides, the continuous change in the direction of the axis of the wavelength, during which the axis is perpendicular to the direction of polarization.