Fiber Optic Wiki

Description of geometrical optics

November 18, 2011

Geometrical optics, or ray optics, describes light propagation in terms of "rays". The "ray" in geometric optics is an abstraction, or "instrument", which can be used to approximately model how light will propagate. Light rays are defined to propagate in a rectilinear path as far as they travel in a homogeneous medium. Rays bend (and may split in two) at the interface between two dissimilar media, may curve in a medium where the refractive index changes, and may be absorbed and reflected.

Equilibrium mode distribution

November 18, 2011

The equilibrium mode [power] distribution of light travelling in an optical waveguide or fiber, is the distribution of light that is no longer changing with fibre length or with input modal excitation. This phenomenon requires both mode filtering and mode mixing to occur in the fibre to produce a state that is independent of the mode power distribution launched by the light source. At propagation distances exceeding the equilibrium length, intramodal pulse distortion increases (bandwidth decreases) as the square root of length.

Erbium-doped waveguide amplifier

November 18, 2011

An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed. Optical amplifiers are important in optical communication and laser physics.

Transmission medium is a material substance

November 17, 2011

A transmission medium (plural transmission media) is a material substance (solid, liquid, gas, or plasma) that can propagate energy waves. For example, the transmission medium for sound received by the ears is usually air, but solids and liquids may also act as transmission media for sound.

Telecommunications purposes

November 17, 2011

Many transmission media are used as communications channels.For telecommunications purposes in the United States, Federal Standard 1037C, transmission media are classified as one of the following: Guided (or bounded)—waves are guided along a solid medium such as a transmission line.Wireless (or unguided)—transmission and reception are achieved by means of an antenna.Wireless media may carry surface waves or skywaves, either longitudinally or transversely, and are so classified.

A half-duplex (HDX) system

November 17, 2011

A half-duplex (HDX) system provides communication in both directions, but only one direction at a time (not simultaneously). Typically, once a party begins receiving a signal, it must wait for the transmitter to stop transmitting, before replying (antennas are of trans-receiver type in these devices, so as to transmit and receive the signal as well).

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