Photonics Dictionary

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.

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

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.

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.

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 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.

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.

In an optical waveguide, the refractive index as a function of radius.

A thin-film device containing miniature optical components connected via optical waveguides on a transparent dielectric substrate, whose lenses, detectors, filters, couplers and so forth perform...

Integrated photonics is a field of study and technology that involves the integration of optical components, such as lasers, modulators, detectors, and waveguides, on a single chip or substrate. The...

A method of fabricating a graded-index optical waveguide by means of an ion exchange process.

A power loss caused by transverse or lateral deviation from optimum alignment of source to optical waveguide, waveguide to waveguide, or waveguide to detector.

The numerical aperture of an optical system used to couple (launch) power into an optical waveguide.

In an optical waveguide, a mode whose field decays monotonically for a finite distance in the transverse direction but which becomes oscillatory everywhere beyond that finite distance.

In an optical waveguide, a ray for which geometric optics would predict total internal reflection at the core boundary, but which suffers loss by virtue of the curved core boundary.

In an optical waveguide, that loss attributable to macrobending. Macrobending usually causes little or no radiative loss.

A theoretical analysis of radiation loss from planar optical waveguides due to scattering by surface irregularities/surface roughness of the walls of the waveguide.

In an optical waveguide, the exchange of power/energy among modes.

The number of bound modes that an optical waveguide is capable of supporting.

In an optical waveguide,- typically a multimode fiber - the distortion resulting from differential mode delay, i.e. axial rays (modes), with the shortest path length, will have the shortest...

The combination of two or more signals for transmission along a single wire, path or carrier. In most optical communication systems this is referred to as wavelength division multiplexing, in which...

Direct conversion of a photon from one wavelength to a lower energy photon of another wavelength(s) due to inelastic scattering. In an optical waveguide, nonlinear scattering is usually not important...

A casting consisting of an optical material molded into the desired geometry for grinding, polishing or, in the case of optical waveguides, drawing to the final optical-mechanical specifications.

An optical waveguide having a silica core and a plastic cladding.

An instrument that measures the angle at which a prism can couple laser light into an optical waveguide; used to determine the thickness and refractive index of thin films in integrated optical...

In an optical waveguide, that dispersion attributable to the variation of refractive index profile with wavelength. The profile variation has two contributing factors: variation in refractive index...

A mode in an optical waveguide whose fields are transversely oscillatory everywhere external to the waveguide. It exists even in the limit of zero wavelength.

A light ray that has had its direction altered because of its traversing an air-to-glass interface at some angle. In an optical waveguide, a ray that is refracted from the core into the cladding.

Sapphire refers to a crystalline form of aluminum oxide (Al2O3) that is used in various optical and photonic applications due to its exceptional optical, mechanical, and thermal properties. Sapphire...

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 wave that is guided by the interface between two different media or by a refractive index gradient in the medium. The field components of the wave may exist (in principle) throughout space, even to...