Optical Terminology CheatSheet
1. ADM Add Drop Multiplexer
Bandwidth switching is used to implement broadband management, which allows different VCs between
two STM-N signals to be interconnected, and has various interface signals (PDH) specified by G.703
without tapping and terminating the overall signal. Or the STM-N signal (SDH) is connected to any branch
in the STM-M.
2. AON Active Optical Network
The active optical network is a point-to-multipoint optical communication system consisting of an ONU, an
optical remote terminal OLT, and an optical fiber transmission line.
3. APON ATM Passive Optical Network ATM
An ideal long-term solution that combines ATM multi-service multi-bitrate support and passive optical
network transparent broadband transmission capabilities, represents the latest development direction of
broadband access technology for the 21st century.
4. ADSL Asymmetric Digital Subscriber Line
Asymmetric Digital Subscriber Line System ADSL is a digital subscriber line DSL system that uses
discrete multi-tone DMT line codes.
5. AA Adaptive Antenna
An antenna provides a beam that is directed at a target, such as an antenna of a mobile phone, capable
of automatically adjusting power as the target moves, also known as a smart antenna (SMART
ANTENNA).
6. ADPCM Adaptive Differential Pulse Code Modulation
An encoding technique that reduces the number of bits of analog sampling from 8 bits to 3 to 4 bits to
complete the compression of the transmitted signal. ITU-T recommends G.721 to define an algorithm for
32-bit ADPCM (8000 samples per second. Each sample is 4 bits long, and its transmission capacity is
doubled compared to conventional PCM coding.
7. ADFE Automatic Decree Feedback Equalizer
An equalizer technique that utilizes the determined signal as an input signal to the backward tap to
eliminate the effects of noise on the backward tap signal.
8. AMI Alternate Mark Inversion
A coding technique commonly used in digital transmission, with logic 0 represented by a null level and
logic 1 represented by alternating positive and negative voltages.
9. AON All Optical Net
That is, the signal channel between the network and the end user node still maintains the form of light,
that is, the end-to-end all-optical path, and there is no photoelectric converter in the middle. In this way,
there is no obstacle to photoelectric conversion in the flow of the optical signal in the network, and the
information transmission process does not need to face the difficulty in processing the information rate of
the electronic device.
10. AOWC All Optical Wave Converter
A device that directly converts information from one wavelength of light to another without electrical
domain processing.
11. ASK Amplitude Shift Keying
A keying technique that corresponds to a binary modulated signal that switches between on and off, also
known as ON-OFF keying.
12. ATPC Automatic Transfer Power Control
The point of the technology is that the output power of the microwave transmitter changes in the ATPC
control range by automatically tracking the change in the receiving level of the receiving means. It has the
advantages of reducing interference to adjacent systems, reducing the upper attenuation problem,
reducing DC power consumption, improving the residual error characteristics, and increasing the output
power by an additional 2 dB under fading conditions.
13. AWF All Wave Fiber
The water peak of the fiber at 1383 nm is eliminated, so that more than 120 new wavelengths (interval
100 GHz) can be added in the 1350-1450 nm band. It is very beneficial for users of the urban access
network.
14. AU Administrative Unit
It provides an information structure for the adaptation function between the higher-order channel layer
and the multiplex section layer.
15. AUG Administrative Unit Group
It consists of one or more management units that determine the location that occupy a fixed position in
the STM-N payload.
16. APD Avalanche Diode
A highly sensitive detector that utilizes an avalanche multiplication effect to multiply photocurrent.
17. BA Booster(power) Amplifier
An optical amplifier that compensates for the loss of the optical multiplexer and increases the fiber input
power.
18. BBER Background Block Error Ratio
For a certain test time, the ratio of the number of BBEs present at the available time to the total number of
blocks deducting the unavailable time and all blocks during the SES.
19. BR Basic Rate Access
ITU-T defines an interface rate for narrowband ISDN, also known as 2B+D, B channel 64K is the bearer
channel, and D channel 16K is the digital signaling channel.
20. Bluetooth
It’s a wireless LAN standard that is jointly developed by equipment manufacturers and has a coverage of
10M, a working frequency band of 2.4G, and a transmission rate of approximately 1M.
21. C Band C
That is, the operating wavelength is in the range of 1525 to 1560 nm, and the bandwidth is about 35 nm.
22. Chirp
When the single longitudinal mode laser is operated in direct modulation, the change of the injection
current causes a change in the carrier density, which in turn changes the refractive index of the active
region, and as a result, the optical path length of the laser cavity changes accordingly. Causes the
oscillation wavelength to drift with time. It is generally necessary to overcome it with an external
modulation technique.
23. C Container C
The information structure for loading various rate service signals is denoted as C-n (11, 12, 2, 3, 4).
24. CSMA/CD Carrier Sense Multiple Access with Collision Detection
A multiple access technology applied to wired local area networks.
25. CSMA/CA Carrier Sense Multiple Access with Collision Avoidance
Since wireless products are not easy to detect whether there is a conflict in the channel, 802.11 defines a
new protocol, namely (CSMA/CA). On the one hand, carrier sensing–checking whether the channel is
idle; on the other hand, avoiding collisions–the probability of signal collision occurring when the channel is
not idle, waiting through random time until a new idle channel occurs, so that the signal collision occurs.
Minimize to a minimum. Not only that, but to make the system more stable, 802.11 also provides
CSMA/CA with acknowledgement frame ACK. A signal collision can occur in the event of other noise
interference, or due to a failure of the interception, and this ACK working at the MAC layer can provide
fast recovery capability at this time.
26. CNR Carrier to Noise Ratio
The ratio of carrier level to noise level before any modulation is applied.
27. CP Cross polarization
Two antenna systems use the same frequency but one uses horizontal polarization and the other uses
vertical polarization to improve spectrum utilization.
28. DCF Dispersion Compensating Fiber
It is a large negative dispersion fiber, which is a new type of fiber designed for the 1310nm design. A
certain dispersion compensation fiber is added to the G.652 fiber to perform dispersion compensation to
ensure that the total dispersion of the entire fiber line is zero.
29. DFF Dispersion-flattened Fiber
A wide range of dispersions from 1.3um to 1.55um can be used to achieve very low, virtually zerodispersion fibers.
30. DR Diversity Receiver
Diversity reception is a measure to reduce the impact caused by fading by selecting or synthesizing two
or more receiver outputs with less correlation (ie, simultaneous quality deterioration). Specifically, it can
be divided into different ways such as spatial diversity, frequency diversity, polarization diversity, and
angle diversity.
31. DPT Dynamic Packet Transport
This is a new transmission method proposed by Cisco – IP-optimized optical transmission technology.
This technology provides high efficiency in bandwidth usage, richness of service categories, and
advanced self-healing capabilities of the network.
32. ODM Optical Division ltiplexer
Multiple wavelengths are divided into individual fibers to separate the channels.
33. DSF Dispersion-Shifted Fiber
Known as the best single-mode fiber at 1550 nm, this fiber is designed to match the fiber’s refractive
index profile to zero-dispersion to the 1550 nm window, which matches the minimum window of the fiber,
making ultra-high-speed and ultra-long-range transmission possible.
34. DTM Dynamic Synchronous Transfer Mode
A new technology based on high speed circuit switching and dynamic time slot allocation. As the second
layer of switching/transmission technology, DTM has stronger bandwidth management capabilities and
adapts to the continuous expansion of fiber bandwidth.
35. DWDM Dense Wavelength Division Multiplexing
Multiple optical multiplexing of the same low loss window, relative to coarse wavelength division
multiplexing of optical multiplexing of different low loss windows.
36. DLC Digital loop carrier
Active optical network for densely populated areas
37. DXC Digital cross connect equipment
A device that has one or more quasi-synchronous digital hierarchy (G.702) or digital system (G.707)
signal ports that can be controllably connected and reconnected between any port signal rate (and its
sub-rates).
38. EA Electricity Absorb Modulation
A loss modulator that operates at the wavelength of the absorption region of the modulator material.
When the modulator is unbiased, the wavelength is in an on state. As the bias voltage on the modulator
increases, the absorption coefficient at the original wavelength becomes larger, the modulator becomes
off, and the on/off state of the modulator is the light intensity modulation.
39. EB Error Block
The error performance for high bit rate channels in an SDH network is a “block”, a collection of
consecutive bits transmitted in a channel. When an error occurs in any bit within a block, the block is said
to be a block error.
40. ECC Embedded Control Channel
The embedded control channel that transmits the network management information has a physical
channel of DCC and adopts a seven-layer protocol stack required by ITU-T G.784.
41. EDFA Erbium-doped Fiber Amplifier
When fabricating the fiber, a special process is used to incorporate a very small concentration of barium
ions in the core layer deposition to produce a corresponding erbium-doped fiber. The doped ions in the
fiber are excited to the metastable high-excited state after being excited by the pump light, and stimulated
radiation is generated under the signal light to form a coherent amplification of the signal light. The EDFA
works in the 1550 window. The commercial EDFA has low noise, good gain curve, large amplifier
bandwidth, compatibility with wavelength division multiplexing (WDM) system, high pumping efficiency,
stable working performance and mature technology, and is favored in modern long-distance high-speed
optical communication systems. At present, “EDFA” + Dense Wavelength Division Multiplexing (DWDM) +
Non-Zero Dispersive Fiber (NZDF) + Photonic Integration (PIC) is becoming the main technical direction
of long-distance high-speed optical fiber communication lines in the world.
42. EDFL Erbium-doped Fiber Laser
A type of fiber laser that emits light at a wavelength of 1550 nm and consists of a doped fiber and an
optical pump and other related optical components, such as a wavelength selector, a polarization
controller, an input/output coupler, etc., having a low threshold, and Compatible with fiber-optic
communication systems. In particular, the tunable circular EDFL has a large tuning range and high output
power, and becomes the mainstream of tunable lasers. The main types are polished tunable WDM
devices, DFB type, fiber birefringence tuning type, and piezoelectric tuning fiber FP etalon. Type and so
on. EDFL is suitable for high-capacity long-haul fiber-optic communications and WDM systems.
43. ES Errored Second
When a certain one second has one or more error blocks, the second is called a block error second.
44. ESR Errored Second Ratio
The ratio of the number of ESs present at the available time to the total number of seconds for a certain
test time.
45. FEC Forward Error Correction
It is a data encoding technology. The error detection during transmission is verified by the receiver, and if
there is an error, the sender is notified to resend. It allows re-encoding from a low bit error encoded data
to form a column of error free data streams.
46. FWM Four-wave Mixing
Four-Wave Mixing (FWM), also known as four-phonon mixing, occurs when two or three light waves of
different wavelengths interact to produce new light waves of so-called mixing products or sidebands at
other wavelengths. These lights can affect normal communication. This nonlinear optical effect is called
four-wave mixing.
47. FDMA Frequency Division Multiple Access
The total frequency band of the communication system is divided into a number of equally spaced
channels (or channels), and the channels are reassigned to different users. These channels do not
overlap each other.
48. FTTB Fiber to the Building
ONU is placed in the building
49. FTTC Fiber to the Curb
ONU is placed on the roadside
50. FTTH Fiber to the Home
ONU is at home
51. FA Frequency agility
Refers to the ability of the transmitting system to automatically hop to adapt to the environment according
to changes in external conditions.
52. CSMF Common Single Mode Fiber
A single-mode fiber that meets the requirements of ITU-T.G.652, often referred to as a non-dispersionshifted fiber, has a zero dispersion in the low-loss region of the 1.3um window and operates at a
wavelength of 1310 nm (loss of 0.36 dB/km). With the successful advancement of the fiber optic cable
industry and semiconductor laser technology, the operating wavelength of the fiber line can be transferred
to a lower loss (0.22 dB/km) 1550 nm fiber window.
53. DSF Dispersion-Shifted Fiber
A single-mode fiber that meets the requirements of ITU-T G.653 has a zero-dispersion wavelength shifted
to a very low loss of 1550 nm.
54. GE Gigabit Ethernet
The Gigabit Ethernet standard was officially launched in October 1997 with a maximum transfer rate of 1
Gbps and is backward compatible with Ethernet technology and Fast Ethernet technology.
55. GIF Graded Index Fiber
Light travels in a sinusoidal shape with a bandwidth of 1-2 GHz.km, which is used for some LANs that are
not too fast.
56. GS-EDFA Gain Shifted Erbium-doped Fiber Amplifier
By controlling the degree of particle inversion of the doped fiber, the 1570-1600 nm band is amplified, and
it can be combined with a common EDFA to obtain a broadband amplifier having a bandwidth of about 80
nm.
57. GVD Group Velocity Dispersion
In high-speed and large-capacity optical fiber communication, the shape of the optical pulse envelope
changes due to the nonlinearity of the optical fiber medium. This change affecting the reception of the
optical signal is called group velocity dispersion, and the group velocity dispersion causes the
transmission waveform. Broadening. G.654 Cut-off wavelength shifting single-mode fiber This focus of
fiber design considerations is to reduce the rate of 1550nm. The zero dispersion point is around 1310nm,
so the dispersion at 1550nm is higher, which can be greater than 18ps/(nm.km). A single longitudinal
mode laser can be used to eliminate the effects of dispersion. It is mainly used for submarine
communication fiber communication with a long regenerative distance.
58. HPF High Pass Filter
It’s a filter that allows radio waves that exceed a certain frequency to pass almost without attenuation,
while other waves below this frequency band are severely attenuated.
59. HRDS Hypothetical Reference Digital Section
It is a degree model with a certain length and performance specification, which can be used as a
reference model for indicator allocation. For the SDH number field, there are three lengths of 420km,
280km and 50km.
60. IDLC Integrated DLC
Broadband active optical network, ie Integrated Digital Loop Carrier System (IDLC) is a transmission
platform based on SDH or PDH, which can provide PSTN, ISDN, B-ISDN, DDN, LANE, Internet and
digital video services for centralized user areas. Access is also an ideal way to integrate broadband
access and has great potential for development.
61. IDEN Integrated Digital Enhanced Networks
The iDEN system was introduced in Los Angeles in 1994. It is a digital cluster system proposed by
Motorola. It works in the 800MHz frequency range. After about three years of promotion, it has been put
into commercial application in 13 countries in North America, South America and Asia. Its main feature is
that it can be compatible with GSM, suitable for large networks and more suitable for PAMR applications.
62. IEEE 802.3
CSMA/CD LAN, the Ethernet standard.
63. IEEE 802.11
The wireless LAN technology standard promulgated in 1997, the IEEE 802.11 specification defines three
physical layer (PHY) options: infrared, direct sequence spread spectrum (DSSS), and frequency hopping
spread spectrum (FHSS). Since the wireless LAN transmission medium (microwave, infrared) is very
different from the wired medium, there are some new technical problems objectively. For this reason, the
IEEE802.11 protocol specifies some crucial technical mechanisms such as CSMA/CA protocol, RTS/
CTS protocol, etc. In August 1999, the 802.11 standard was further refined and revised. Two new
contents, 802.11a and 802.11b, were added, which expanded the standard physical layer and MAC layer
specifications.
64. Jitter
One of the important transmission characteristics of the SDH optical transmission network is defined as
the short-term deviation of the effective moments of the digital signal from the theoretical specified time
position.
65. K Band K
10G-12G for satellite communications.
66. Ku Band Ku
12G-14G for multi-satellite communication.
67. LA Line Amplifier
An optical amplifier that compensates for fiber loss on the trunk line.
68. LEAF Large Effective Area Fiber
Single-mode non-zero dispersion-shifted fiber, working in the 1550nm window; compared with the
standard non-zero dispersion-shifted fiber, it has a larger “effective area” and the effective area is
increased to 72um2 or more, thus a large power bearing capacity. For the use of high output power
doped fiber amplifiers, namely EDFA and dense wavelength division multiplexing technology networks.
69. LANE LAN Emulation
When ATM switching is exchanged with Ethernet, a simulation process for ATM cells is required.
70. LMDS Local Multipoint Distribution Service
A very popular broadband wireless access system that utilizes spread spectrum and polarization
techniques. The base station covers approximately 2-10 KM and can provide up to 4.8 G of bandwidth.
Suitable for wireless access in densely populated areas.
71. LOF Loss of Frame
After the frame out-of-synchronization state lasts for 3 ms, the SDH device should enter the frame loss
state; and when the STM-N signal is continuously in the fixed frame state for at least 1 ms, the SDH
device should exit the frame loss state.
72. LOS Loss of Signal
When the received optical signal power is always below a certain threshold value Pd (Pd corresponds to
BER ≥ 10-3) for a given time (10 us or longer), the device enters the LOS state.
73. LOP Loss of Pointer
When no valid pointer is found for 8 consecutive frames, or 8 consecutive new data flags (NDF) are
enabled, the device should enter the LOP state; and when 3 consecutive valid pointers or cascade
indications with normal NDF are detected. This device should exit the LOP state.
74. MI Modulation Instability
Modulation instability instantaneously breaks a continuous wave (CW) signal or a pulse, making them a
modulated shape. A quasi-monochromatic signal spontaneously produces two symmetric frequency
sidebands. This phenomenon may be observed in areas above the zero dispersion wavelength.
75. MLCM Multi-Level Coded Modulation
A complex code modulation method can be regarded as a delete trellis coded 64QAM mode. The design
idea is the same as TCM, which brings the redundancy generated by the error correction code to the
most error-prone symbols to maximize the coding redundancy.
76. MMF Multi Mode Fiber
Two or more modes of fiber can be propagated at the wavelengths considered.
77. MMDS Multichannel Multipoint Distribution Service
Often referred to as a wireless cable, a wireless system is typically used to transmit image traffic.
78. MVDS Multipoint Video Distribution Service
A wireless local loop technology developed by the UK, running at 40.5G to 42.5G, is very similar to
LMDS, but is mainly used in video on demand services.
79. MQAM Quadrature Amplitude Modulation
Multi-ary quadrature amplitude modulation is a carrier control method widely used in medium and largecapacity digital microwave communication systems. This method has a high spectrum utilization rate.
When the modulation number is high, the distribution of the signal vector set is also reasonable, and it is
also convenient to implement. At present, 64QAM, 128QAM, etc., which are widely used in large-capacity
digital microwave communication systems such as SDH digital microwave and LMDS, belong to this
modulation mode.
80. MSOH Multiplex Section Overhead
Responsible for managing the multiplex section, which can only be accessed at the terminal device.
81. MSP Multiplexer Section Protection
A protection method for SDH optical fiber communication, the service volume of protection is based on
the multiplex section, and the switching is determined according to the merits of the multiplex section
signal between each node. When the multiplex section fails, the multiplex section service signal between
the entire nodes is turned to the protection section.
82. MZ Mach-Zehnder
The modulator splits the input light into two equal signals into the two optical branches of the modulator.
The materials used in these two optical branches are electro-optic materials whose refractive index varies
with the magnitude of the externally applied electrical signal. Since the refractive index change of the
optical branch causes a change in the phase of the signal, when the output ends of the two branch signal
modulators are combined again, the synthesized optical signal will be an interference signal of varying
intensity, equivalent to the electrical signal. The change is converted into a change in the optical signal,
and the modulation of the light intensity is achieved.
83. NA Numerical Aperture
It indicates the ability of the fiber to receive and transmit light. The larger the NA, the stronger the ability of
the fiber to receive light, and the higher the coupling efficiency from the source to the fiber.
84. NC Network Connection
Network connections are cascaded by subnet connections and/or link connections and can be seen as an
abstract representation of this complex entity. It transparently delivers end-to-end information over a layer
network, delimited by a terminal connection point (TCP).
85. NEL Network Element Layer
The most basic management layer is responsible for the management of configuration, fault, and
performance of a single network element.
86. NML Network Management Layer
Manage, monitor, and control the network areas of different manufacturers.
87. NE Network Element
The basic unit that constitutes the network.
88. NZDSF Non Zero Dispersion Shifted Fiber
Single-mode fiber that meets ITU-TG655 requirements is a dispersion-shifted fiber, but the dispersion is
not zero at 1550 nm (according to ITU-TG655, the dispersion value in the range of 1530-1565 nm is 0.16.0 ps/nm. Km) to balance nonlinear effects such as four-wave mixing. Commercial fibers are like
TrueWave fiber from AT&T, Corning’s SMF-LS fiber (which has a zero-dispersion wavelength of 1567.5
nm, a typical zero dispersion of 0.07 ps/nm2.km) and Corning’s LEAF fiber.
89. NNI Network Node Interface
It can be a simple node with only multiplexing functions, or a complex node with transmission,
multiplexing, cross-connect, and switching functions.
90. OADM Optical Add Drop Multiplexe
Its function is to select the optical signal from the transmission device to the local optical signal, and to
send the optical signal of the local user to the user of another node without affecting the transmission of
other wavelength channels, that is to say, the OADM is realized in the optical domain. The function of the
electrical add/drop multiplexer in the traditional SDH device in the time domain.
91. OA&M Operations, Administration and Maintenance
A set of network management features for network performance monitoring, failure detection, and system
troubleshooting and protection.
92. OFA Optical Fiber Amplifier
It refers to a new all-optical amplifier used in fiber-optic communication lines to achieve signal
amplification. According to its position and role in the fiber line, it is generally divided into relay
amplification, preamplification and power amplification.
93. ODN Optical Distribution Network
Optical distribution network, consisting of passive optical components
94. OAN Optical Access Network
Access network technology based on optical transmission
95. OBD Optical Branching Device Optical Splitter
Passive optical power splitter (coupler) that distributes the downlink signal and couples the upstream
signal
96. OLT Optical Line Terminal
Provides an interface between the network side and the local switch, and connects one or more
ODN/ODTs to communicate with the ONUs on the user side.