Photonics Dictionary

A curve expressing an optical fiber's total transmitted power as a function of its launch angle at the input.

A protective jacket added to an optical fiber to facilitate use in harsh environments. Armor usually consists of steel or aluminum and is placed between the fiber and its outer jacket.

A vapor-phase oxidation process for fabricating graded-index optical fibers. It differs from outside vapor phase deposition in that the preform is developed radially rather than longitudinally. An...

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

A characteristic of optical fiber used to calculate the fiber's ability to maintain polarization. The beat length describes the length required for the polarization to rotate 360 degrees. For a given...

The loss of optical power in an optical fiber because radiation escapes through its bends. The radiation loss caused by fiber bending is proportional to the bend radius.

The radius of curvature that an optical fiber can bend without breaking.

A technique developed by British Telecom in which the viscous drag of air is used to install optical fibers in narrow plastic tubes.

1. A group of optical fibers that are fused and then treated to produce a vacuum-tight optical fiber cone or plate. 2. An artificial crystal in its raw state, after generation but prior to cutting or...

A filter that separates light into many colors via Bragg's law. Generally refers to a fiber Bragg grating used in optical communications to separate wavelengths.

Brillouin scattering is a phenomenon in physics where an incident electromagnetic wave (usually light) interacts with acoustic phonons (quantized lattice vibrations) in a material, resulting in the...

1. In fiber optics, a protective material applied as an optical fiber cover that has no optical function. 2. In image processing, a peripheral that stores data between two active processing stages.

Chalcogenide refers to a class of compounds containing elements from group 16 of the periodic table, which includes sulfur (S), selenium (Se), and tellurium (Te). These elements are known as...

The number of channels per unit bandwidth handled by a single optical fiber.

The angle at which a given mode propagates down an optical fiber.

1. A localized fracture at the end of a cleaved optical fiber or on a glass surface. 2. An integrated circuit.

A laser whose pulses are expanded, using gratings and optical fibers, before amplification and compressed to increase beam intensity without damage to the optical train.

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...

A mechanism or device, especially a coating with a refractive index equal to or slightly greater than that of an optical fiber's cladding, that removes modes propagating through the cladding by...

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

A fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser produces an optical wave that is modulated in amplitude, phase or frequency by...

A coherent fiber bundle (CFB), also known as a coherent fiber optic bundle, is an assembly of multiple optical fibers arranged in a specific geometric pattern to maintain the spatial coherence of...

The process of linking optical fiber end to end.

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.

The fraction of available output from a radiant source that is coupled and transmitted by an optical fiber.

The physical limit of an optical fiber or cable to withstand an applied force or weight perpendicular to the axis of the fiber.

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.

A device used to delay transmission of a signal for functions such as memory loops, sequential processing or built-in testing. The delay can be achieved by coiling long lengths of coaxial cable or...

The variation in attenuation among the propagating modes of an optical fiber.

A variation in propagation delay caused by differences in group velocity among modes of an optical fiber. Also called multimode group delay, this effect is commonly due to imperfections or any...

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

A diode laser is a type of laser that uses a semiconductor diode as the active medium to generate coherent light. Semiconductor diodes are electronic devices that conduct electricity primarily in one...

In a fiber optic transmission system, the conversion of received optical pulses directly to an electrical signal.

A type of glass optical fiber that provides low pulse dispersion over a broad portion of the light spectrum and as a result can operate at 1300-nm and 1550-nm wavelengths simultaneously.

A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion, which is the phenomenon where different wavelengths of light travel at...

The end of an optical fiber farthest from the source of illumination.

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...

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.

Optical fiber capable of operating at both a shorter and a longer wavelength.

A system for fabricating optical fiber, consisting of a furnace that heats the materials, a polymer coating stage, a capstan-pulling apparatus that free-draws the preform into a fiber and a drum on...

Stress applied to an optical fiber at a constant rate.

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...