Photonics Dictionary

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...

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

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...

An acousto-optic modulator (AOM) is a device that utilizes the interaction between sound waves and light waves to modulate or control the intensity, frequency, phase, or direction of laser beams. It...

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.

An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to minimize unwanted reflections and increase the transmission of light...

An aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical surface profile. Unlike traditional spherical mirrors, which have a curved...

An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical elements in a sample by measuring the absorption of light at...

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

A beamsplitter is an optical device used to divide a beam of light into two or more separate beams, typically by reflecting a portion of the incident light while transmitting the remainder....

A blackbody source, often simply referred to as a blackbody, is a theoretical or practical physical object that absorbs all electromagnetic radiation incident upon it and emits radiation in a...

A blue diode laser is a type of semiconductor laser that emits light in the blue wavelength range of the electromagnetic spectrum, typically between 400 and 500 nanometers. Diode lasers are compact,...

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...

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

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 distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth light with precise control over the wavelength. It achieves this through a...

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 Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It consists of a periodic modulation of the refractive index along the length...

A fiber optic spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to transmit light from a source to a spectrometer unit, where the light is...

The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one location to another. Fiber optics is based off of the principle of total...

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...

A fiber-coupled photoconductive antenna (FCPA) is a type of optoelectronic device that combines a photoconductive antenna with optical fibers for the purpose of generating or detecting terahertz...

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.