1) Crosstalk (XT) is any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. 2) Waveguide is a structure that guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave. The original and most common[1] meaning is a hollow conductive metal pipe used to carry high frequency radio waves, particularly microwaves.

3) Fiber to the x (FTTx) is a generic term for any broadband network architecture using optical Fiber to replace all or part of the usual metal local loop used for last mile telecommunications.

4) Simplex communication refers to communication that occurs in one direction only.

5) A half-duplex (HDX) system provides communication in both directions, but only one direction at a time (not simultaneously).

6) A full-duplex (FDX), or sometimes double-duplex system, allows communication in both directions, and, unlike half-duplex, allows this to happen simultaneously.

7) Photodiode is a type of photo detector capable of converting light into either current or voltage, depending upon the mode of operation.

8) Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave.

9) Analog (or analogue) transmission is a transmission method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable.

10) Data transmission, digital transmission, or digital communications is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel.

11) Sample rate defines the number of samples per unit of time (usually seconds) taken from a continuous signal to make a discrete signal.

12) Electromagnetic Wave a wave of energy having a frequency within the electromagnetic spectrum and propagated as a periodic disturbance of the electromagnetic field when an electric charge oscillates or accelerates.

13) Refraction is the bending of light as it passes from one substance to another. Here, the light ray passes from air to glass and back to air. The bending is caused by the differences in density between the two substances.

14) Growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells,[1] or small plants like the mossPhyscomitrella patens.

15) Total internal reflection is an optical phenomenon that happens when a ray of light strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface.

16) The reflection of a portion of the light incident on a planar surface (i.e., the interface) between two media having different refractive indexes.

17) Tensile strength measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks.

18) Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency.

19) Bandwidth (signal processing) or analog bandwidth, frequency bandwidth or radio bandwidth: a measure of the width of a range of frequencies, measured in hertz.

20) A form of charge, designated positive, negative, or zero, found on the elementary particles that make up all known matter.

21) Absorption is the process when one thing becomes part of another thing or the process of something soaking in, either literally or figuratively.

22) Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which they pass.

23) Also known as modal equilibrium. Referring to a state in which optical power is evenly distributed across all modes, i.e., physical paths in an optical fiber. See also mode and optical fiber.

24) Personal protective equipment (PPE) refers to protective clothing, helmets, goggles, or other garment or equipment designed to protect the wearer's body from injury by blunt impacts, electrical hazards, heat, chemicals, and infection, for job-related occupational safety and health purposes, and in sports, martial arts, combat, etc.

25) An acquired behavior pattern regularly followed until it has become almost involuntary.