Photonics Dictionary

Also known as all-glass fiber. A fiber with both a silica core and a silica cladding, regardless of the presence of a polymer overcoat or buffer.

In fiber optics, the use of a detector to study the range of refractive indices achieved at various wavelengths. This information is calculated electronically to establish the divergence between...

In the fabrication of an optical fiber, a layer that can be used to create a boundary against OH-ion diffusion into the core.

The low-refractive-index material that surrounds the core of an optical fiber to contain core light while protecting against surface contaminant scattering. In all-glass fibers, the cladding is...

In fiber optics, the glass that is found around the glass core of the fiber, and that has a lower refractive index than the fiber.

A ray that is reflected into the core of an optical fiber from the outer surface of the cladding.

The distance between the center of the two concentric circles of an optical fiber that designate the diameter of the cladding and the center of the two concentric circles that designate the diameter...

Energy loss encountered at connectors in optical fiber transmission systems. The major contributors are mutual core displacement and fiber axis tilt. It is observed in both permanent splices and...

The light-conducting portion of an optical fiber, defined by the region of high refractive index.

A semispherical or conical lens created directly on the core of an optical fiber to focus light from a laser into the fiber core.

An optical fiber, usually a single-mode fiber, that has an outer cladding with nearly the same index of refraction as the core and an inner cladding with a very low index of refraction.

Double-clad fiber (DCF) is a specialized optical fiber that features two concentric cladding layers surrounding a core. The design of double-clad fibers allows them to be used in various...

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.

A change in the refractive index of an optical fiber caused by variation in the length of the fiber core in response to mechanical stress.

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...

An optical fiber that can be used to amplify an optical input. Erbium rare earth ions are added to the fiber core material as a dopant in typical levels of a few hundred parts per million. The fiber...

An erbium-doped fiber laser (EDFL) is a type of laser that uses an optical fiber doped with erbium ions (Er³+) as the gain medium. These lasers are widely used in telecommunications, medical...

The mechanical centerline through the core of an optical fiber.

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 phenomenon in which high optical power, encountering an imperfection in an optical fiber, destroys the fiber's core and causes damage to back-propagate down the fiber. It is caused by classic...

Fiber joints, also known as fiber optic splices, refer to the connection points where two optical fibers are permanently joined together to form a continuous optical transmission path. These joints...

A method of optical fiber coupling in which the fibers are ground down to expose their cores and placed together to allow light pulses to transfer from one to the other.

A fiber laser is a type of laser in which the active gain medium is an optical fiber doped with rare-earth ions such as erbium, ytterbium, or neodymium. Fiber lasers generate coherent light through...

A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and other components that are assembled together to facilitate the transmission of...

A fiber optic gyroscope (FOG) is a type of gyroscope that uses the interference of light waves to detect changes in orientation or rotation. It operates based on the principle of the Sagnac effect,...

A fiber optic preform is a cylindrical glass rod or tube used as the starting material for manufacturing optical fibers. It serves as the precursor from which optical fibers are drawn. The process of...

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...

Descriptive of an optical fiber having a core refractive index that decreases almost parabolically and radially outward toward the cladding. This type of fiber combines high bandwidth with moderately...

A type of optical fiber in which a silica core is surrounded by a hard polymer or similar material much stronger than the customary cladding material.

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.

The decrease in the refractive index at the center of a fiber's core, caused by certain fabrication techniques. Also called profile dip.

A material, often a liquid or cement, whose refractive index is nearly equal to the fiber's core index, used to reduce Fresnel reflection from a fiber end face.

Loss intrinsic to the fiber caused by parameter (core dimension, profile parameter) mismatches when two nonidentical fibers are joined.

Optical fiber with a large core, often a step-index fiber; "large'' is at times defined as greater than 85 µm.

Multimode straight fiber capable of transporting linearly polarized light with any incident polarization angle, and in which no form of internal stress can develop that could lead to birefringence.

An optical fiber with a hollow core filled with a liquid material that has a higher refractive index than the solid surrounding it.

A type of fiber optic sensor that detects changes in pressure, vibration, sound level or acceleration by monitoring the ejection of light from the fiber core to the cladding caused by microbending...

Modal bandwidth is a crucial parameter in optical fiber communication systems, particularly in multimode fiber (MMF) systems. It quantifies the ability of a fiber optic link to transmit data at high...

Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the symbol V, given by: where a is waveguide core radius, l is wavelength in vacuum,...

Optical fiber is a thin, flexible, transparent strand or filament made of glass or plastic used for transmitting light signals over long distances with minimal loss of signal quality. It serves as a...

Optical strain sensors are devices that utilize optical principles to measure the deformation or strain experienced by a material under mechanical stress. These sensors convert changes in strain into...

The condition of the numerical aperture or beam diameter of the laser, LED, or other optical source being larger than the optical fiber core or other driven source. Also called overfilled launch...

1. In a photonic interconnect, the number of detectors in a given area. Detectors spaced too closely may give rise to crosstalk. 2. In the cross section of a fiber optic bundle, the ratio of fiber...

The ratio of the active core area of a fiber bundle to the total area at its light-emitting or receiving end.

Fiber in which both core and cladding are made of plastic.

The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to glass-clad fibers to reduce microbend loss and increase mechanical protection.

Plastic optical fiber (POF) is a type of optical fiber made from transparent plastic, typically polymethylmethacrylate (PMMA) or polycarbonate. Unlike traditional glass optical fibers, which are made...