| m: Abbreviation for meter. 39.37". |
| M: Abbreviation for mega. One million or 106. |
| mA: Abbreviation for milliamp. One thousandth of an Amp or 10-3 Amps. |
| MAC: Abbreviation for multiplexed analog components. A video standard
developed by the European community. An enhanced version, HD-MAC delivers
1250 lines at 50 frames per second, HDTV quality. |
| Macrobending: In a
fiber, all macroscopic deviations of the fiber’s axis from a straight line, that will cause light to leak out of the fiber,
causing signal attenuation. |
 |
| MAN (Metropolitan Area
Network): A network covering
an area larger than a local
area network. A series of local area networks, usually two or more,
that cover a metropolitan area. |
 |
| MAP: Abbreviation for
manufacturing automation protocol. Computer programs that run
manufacturing automation systems. |
| Margin: Allowance for attenuation in addition to that explicitly accounted for in system design. |
| Mass Splicing: splicing of many fibers in a cable. |
| Material
Dispersion: Dispersion resulting from the different velocities of each wavelength in a material. |
|
| MBaud: One million symbols of information per second. Equivalent to 1
mb/s for binary signals. |
| Mean Launched
Power: The average power for a continuous valid symbol
sequence coupled into a fiber. |
| Mechanical
Splice: An optical
fiber splice accomplished by fixtures or materials, rather than by thermal fusion. The
capillary splice, illustrated, is one example of a mechanical
splice. |
|
| Medium Access Control (MAC): 1) A
service feature or technique used to permit or deny use of the components
of a communication system. 2) A technique used to define or restrict the
rights of individuals or application programs to obtain data from, or
place data onto, a storage device, or the definition derived from that
technique. |
| Mezzanine
Compression: Contribution level quality encoded high-definition
television signals. Typically split into two levels: high level at 140
Mb/s and low level at 39 Mb/s. For high definition within the studio, 270
Mb/s is being considered. |
| MFD: See mode
field diameter. |
| MH: Abbreviation for medium-haul. A classification of video
performance under RS-250C. Higher performance than long-haul and lower performance than short-haul. |
| MHz: Abbreviation for megahertz. One million Hertz
(cycles per second). |
| Microbending: Mechanical stress on a fiber that introduces local discontinuities, which results in light
leaking from the core to the cladding by a process called mode
coupling. |
 |
| Microwave
Dish: A parabolic shaped antenna used for high-frequency RF
signals. |
| Micrometer: One
millionth of a meter or 10-6 meters.
Abbreviated ¦Ìm . |
| Microsecond: One
millionth of a second or 10-6 seconds.
Abbreviated ¦Ìs. |
| Microwatt: One
millionth of a Watt or 10-6 Watts.
Abbreviated ¦ÌW. |
| Microwave
Transmission: Communication systems using very high-frequency RF
to carry the signal information. |
| MIL-SPEC: Abbreviation for military specification. Performance
specifications issued by the Department of Defense that must be met in
order to pass a MIL-STD. |
| MIL-STD: Abbreviation
for military standard. Standards issued by the Department of
Defense. |
| Minimum Bend
Radius: The smallest radius an optical fiber or fiber cable can
bend before increased attenuation or breakage occurs. |
| Misalignment Loss: The loss of power
resulting from angular
misalignment, lateral
displacement, and fiber end separation. |
| MLM: See multilongitudinal
mode laser. |
| mm: Abbreviation for millimeter. One thousandth of a meter or 10-3 meters. |
| MM: See multimode. |
| Modal Dispersion: See multimode
dispersion. |
| Modal
Noise: Noise that occurs whenever the optical power
propagates through mode-selective devices. It is usually only a factor
with laser light sources. |
| Mode: A single
electromagnetic wave traveling in a fiber. |
| Mode Coupling: The transfer of energy between modes. In a fiber,
mode coupling occurs until equilibrium
mode distribution (EMD) is reached. |
| Mode Evolution: The dynamic process a multilongitudinal
mode laser undergoes whereby the changing distribution of power among
the modes creates a continuously changing envelope of the laser's
spectrum. |
| Mode Field
Diameter (MFD): A measure of distribution of optical power
intensity across the end face of a single-mode
fiber. |
| Mode Filter: A device that removes higher-order modes to simulate equilibrium
mode distribution. A mode filter is most easily
constructed |
 |
| Modem: Acronym for modulator/demodulator.
1) In general, a device that both modulates and demodulates signals. 2) In
computer communications, a device used for converting digital signals
into, and recovering them from, quasi-analog signals suitable for
transmission over analog communications channels such as telephone
lines. |
| Mode
Scrambler: A device that mixes modes to uniform power distribution. |
|
Mode Stripper: A device that removes cladding
modes. |
|
| Modulation: The
process by which the characteristic of one wave (the carrier) modifies
another wave (the signal). Examples include amplitude
modulation (AM), frequency
modulation (FM), and pulse-coded
modulation (PCM). |
Modulation Index: In an intensity-based
system, the modulation index is a measure of how much the modulation
signal affects the light output. It is defined as follows: |
m = (highlevel - lowlevel) / (highlevel +
lowlevel) |
| Modulator: A device
that imposes a signal on a carrier. |
| Monitor:1) a CRT that receives its
signal directly from a VCR, camera, or separate TV tuner for high-quality
picture reproduction. 2) A device used for the real-time temporary display
of computer output data. 3) Software or hardware that is used to
scrutinize and to display, record, supervise, control, or verify the
operations of a system. |
 |
| Monochrome: Black
and white TV signal. |
| Moore
Law: A prediction for the rate of development
of modern electronics. It states that the density
of information storable in silicon roughly doubles
every year. Or, the performance of silicon will
double every eighteen months, with proportional
decreases in cost. For more than two decades
this prediction has held true. Named after Gordon
E. Moore, physicist, cofounder and chairman
emeritus of Intel Corporation. |
| Most
Significant Bit: In a binary code, the bit or bit position that is
assigned to, or represents, the largest quantity or increment that the
code can represent. |
| MPEG: Abbreviation for motion picture experts group.
An international standard for compressing video that provides for high
compression ratios. The standard has two recommendations: MPEG-1
compresses lower-resolution images for videoconferencing and lower-quality
desktop video applications and transmits at around 1.5 Mb/s. MPEG-2 was
devised primarily for delivering compressed television for home
entertainment and is used at CCIR resolution when bit rates exceed 5.0 Mb/s as in hard disk-based
applications. |
| MQW: See multi-quantum
well laser. |
| ms: Abbreviation for
milliseconds. One thousandth of a second or 10-3 seconds. |
| MSO: Abbreviation for multiple service
operator. A telecommunications company that offers more than one service,
e.g. telephone service, Internet access, satellite service, etc. |
| MTBF: Abbreviation for mean time between failure. Time after which 50%
of the units of interest will have failed. Also called MTTF (mean time to
failure). |
| Multilongitudinal Mode (MLM) Laser : An injection laser diode which has a number of longitudinal
modes. |
 |
| Multimode
Dispersion: Dispersion resulting from the different transit lengths of different propagating modes in a
multimode optical fiber. Also called modal dispersion. |
| Multimode (MM) Fiber: An optical
fiber that has a core large enough to propagate more than one mode of
light The typical diameter is 62.5 micrometers. |
 |
| Multimode
Laser Diode (MMLD): Synonym for multilongitudinal
mode laser. |
| Multiple
Reflection Noise (MRN): The fiber optic receiver noise resulting from the interference of delayed signals from two or more
reflection points in a fiber optic span. Also known as multipath
interference. |
| Multiplexer: A
device that combines two or more signals into one output. |
 |
| Multiplexing: The
process by which two or more signals are transmitted over a single
communications channel. Examples include time-division
multiplexing (TDM) and wavelength-division
multiplexing (WDM). |
| Multi-quantum Well (MQW) Laser: A laser structure with a very thin (about 10 nm thick) layer of bulk
semiconductor material sandwiched between the two barrier regions of a
higher bandgap material. This restricts the motion of the electrons and
holes and forces energies for motion to be quantized and only occur at
discrete energies. |
| MUSE: Abbreviation for
multiple sub-nyquist encoder. A high-definition standard developed in
Europe that delivers 1125 lines at 60 frames per second. |
| mV: Abbreviation for
millivolt. One thousandth of a Volt or 10-3 Volts. |
| mW: Abbreviation for milliwatt. One thousandth of a Watt or 10-3 Watts. |
| MZ: Abbreviation for
Mach-Zehnder, a structure used in fiber Bragg
gratings and interferometers.
Named for the two men who developed the underlying principles of the
structure. |
