40/100 Gigabit Ethernet

40GbE and 100GbE are rates of Ethernet protocol (40 and 100) for transmitting data over fiber optic networks. The technology was first defined by the IEEE 802.3ba-2010 standard.

100G OIF Coherent

A 100G long haul DWDM non-pluggable transceiver module modulated as 100G PM-QPSK, with coherent detection on the receive side. This is a full C-band, multi source agreement (MSA) module with single tunable 50GHz, and can reach approximately 2000km without the need for dispersion compensation. The module supports OTU4, usually with internal soft decision forward error correction (SD FEC) capability implemented using a powerful digital signal processing (DSP). The framework for this optical module was defined by the Optical Internetworking Forum (OIF).


400ZR is an Ethernet-based networking interface defined by the Optical Internetworking Forum (OIF). Called an Implementation Agreement, 400ZR specifies 400G optical transmission over a single wavelength for dense wavelength division multiplexing (DWDM) deployments. 400ZR targets edge and relatively short reach DCI applications of up to 120km. The combination of 400G per wavelength and DWDM provides networks with very high capacity interconnect bandwidth.



Attenuation in optical networks refers to a loss of intensity of the light signal over distance in a fiber optic cable. Measured in dB/km, attenuation is a significant factor when planning an optical network and is taken into consideration by any optical engineer. In order to compensate for attenuation, optical amplifiers are often used.


Automatic gain control (AGC) in optical networking refers to a method of automatically adjusting the gain of the receiver to maintain a constant average output level of the wavelength stream in an optic fiber. AGC is usually used in EDFAs as one of two automatic adjustment methods.


Automatic power control (APC) in optical networking refers to a method of automatically adjusting the power (or attenuation) of the receiver to maintain constant average output level for wavelength stream in a fiber optic cable. APC is usually used in EDFAs as one of two automatic adjustment methods.



C-band in optical networking refers to a section of wavelengths (colors) that ranges between 1530nm to 1565nm.


The century form factor pluggable (CFP) is an optical transceiver module typically used for 100GbE and 100G OTU4 OTN data rates, as as a client interface or an uplink coherent interface. The optical interface supports a number of lanes, reaching 10km/40km over single mode (SM) fiber, and 100m over multimode (MM) fiber. The electric interface on the host side comprises 10 lanes of 10G. The CFP supports LR4, ER4 and SR10 optical interfaces on the client side, and coherent tunable transceiver on the DWDM line side, reaching over 1000km without the need for DCM or regeneration sites.


The century form factor pluggable 2 (CFP2), is an optical transceiver module which supports 100GbE and OTN OTU4 data rates. It is a smaller form factor than the CFP and consumes less power, enabling higher port density. The electrical interface depends on the application, for example, 10 lanes of 10G or 4 lanes of 25G. The optical interface is usually 4 lanes of 25G over a single mode fiber.


The century form factor pluggable 2 analog coherent optics (CFP2-ACO) is a transceiver module coupled with a DSP on the host board, for 100G and 200G metro systems. The transceiver is tunable and pluggable, providing cost and power consumption reduction for 100G/200G single wavelength coherent DWDM applications. The transceiver also facilitates pay-as-you-grow benefits, as bandwidth is easily increased by adding transceivers. The CFP2-ACO is popular with system designers because of its multi-source agreement (MSA) form factor, increased bandwidth density, and interoperability with multiple optical transceiver vendors. The CFP2-ACO is dual-rate and enables transmission distance as high as 2500km in 100G DQPSK modulation or 600km in QAM 200G modulation.


The century form factor pluggable 2 digital coherent optics (CFP2-DCO) is a DWDM module that supports 100G and 200G data rates in DCI and long-haul applications. The CFP2-DCO integrates the coherent DSP within the module. The CFP2-DCO a plug-and-play module enables simple and efficient deployment. The module also has digital signal processors which enable users to configure the module in real-time, for changing application needs.


Customer premises equipment (CPE) is carrier or service provider equipment that is located on the customer's premises (physical location) rather than on the carrier or service provider premises, network, or in between. The equipment can be owned by the customer or by the carrier/provider.


Common Public Radio Interface (CPRI™) is a digital radio frequency protocol used in transporting radio signals over fiber in mobile networks. It is commonly used in fronthaul networks. The following CPRI rates are standardized: 614.4Mbit/s, 1228.8 Mbit/s, 2457.6 Mbit/s, 3072.0 Mbit/s, 4915.2 Mbit/s, 6144.0 Mbit/s, 9830.4 Mbit/s.


Crosstalk in optical networks is where information from one channel crosses over into another channel, causing distortion in the transmitted signal. PacketLight's solutions eliminate crosstalk in WDM networks by using independently colored channels (wavelengths).


Coarse wavelength division multiplexing (CWDM) is one of two types of WDM multiplexing technologies (DWDM is the other). CWDM offers up to 18 channels (wavelengths) per each fiber pair, making it a good initial entry point for many organizations. CWDM operates in the spectral range of 1270nm to 1550nm, and each wavelength typically supports up to 10Gb Ethernet, 16G Fibre Channel, and STM-1/STM-4/STM-16. CWDM is primarily used in applications of up to 80km, as the signal waves are spaced further apart and cannot support amplification.


The century small form-factor pluggable (CXP) is an optical transceiver module for transporting 100Gb Ethernet in short distances of up to 100m. The electrical side has 12 lanes of 10G, and hte optical side has 12 lanes of 10G over 12 paralel multimode fibers. In case of a 100G network, only 10 lanes are used. The small form factor of the CXP and its low power consumption, make it a low cost 100G interface.


Dark Fiber

In optical networking, dark fiber is unused (or unlit) fiber, that is ready for use.


Dispersion compensation modules (DCM) are used in long spans of transmission fiber to maintain the integrity of the signal. The DCM provides fixed and tunable dispersion compensation. The DCM is usually placed between two fiber amplifiers, or at the beginning or end of the link, and is installed using the module's input and output fiber connectors.

Demarcation Point

Demarcation point is the physical point in which the network of the carrier or service provider ends and the network of the customer begins. It defines where the carrier's / service provider's responsibility for the network ends. It can also indicate the demarcation (or defining point) between transport Layer-2/3 and the DWDM/OTN Layer-1 infrastructure. The demarcation point includes performance monitoring, loopback and other diagnostic means to isolate issues and detect network faults. In the demarcation point, either the 3R (retiming, reamplifying, and regeneration) or the OTN FEC, ensure an error-free optical layer.

Demultiplexer (Demux)

A demultiplexer (demux) is a device that receives an input signal containing multiple signals and splits it into multiple signals while maintaining the integrity of each signal. In optical networks, the demultiplexer separates one optical signal containing multiple colored signals, into separate channels.


In optical networking wavelength velocity (or speed) is dependent on its frequency. Changes in frequency cause a delay in the light pulse, degrading the optical signal over long distances. Some data rates, such as 10Gb Ethernet, are more sensitive to dispersion than others. To prevent dispersion and ensure the integrity of the optical signal, dispersion compensation modules (DCM) are placed strategically along the optical link.


Dense wave division multiplexing (DWDM) is one of two types of WDM multiplexing technologies. DWDM is a technology with much higher throughput capacity than CWDM transferring data of 10G FC, 10GbE, and STM-64.
Some DWDM systems provide up to 144 wavelengths of mixed service types, and can transport to long distances by integrating amplifiers and dispersion compensators. DWDM technology is more costly, but is a better solution for large capacity data transport and connectivity over long distances.



Erbium-doped fiber amplifier (EDFA) is an optical device that amplifies optical signals without converting them to electrical signals, enabling them to reach longer distances (between 80km and 200km) without intermediary nodes. EDFAs are commonly used in DWDM networks. PacketLight offers three types of EDFAs: inline, boosters, and pre-amplifiers.


Optical encryption solves the need for data security over DWDM and OTN links, and answers requirements and regulations that have been put into place to maintain confidentiality, data integrity, and authentication. Implementing encryption at the optical layer (Layer-1) of the signal has several advantages. Layer-1 supports multiple client protocols, does not allow for omissions and is easier to deploy. Most importantly, encryption on Layer-1 is transparent to the traffic at full bandwidth, without degradation to the link. The optical layer can also detect tapping attempts as it constantly monitors the power levels of the DWDM channels and alerts of any change.

ER4 (100GBase-ER4)

100GBase-ER4 refers to 100Gb Ethernet. It is a port type of an extended range (ER) optic for single mode fiber. It uses four wavelengths in the 1300nm each carrying 25Gb/s for a distance of 40km. The mux/demux of the four wavelengths is built inside the modules, and its interface is dual LC fiber. The ER4 optical modules also supports 100G OTN OTU4 rate.


ESCON (Enterprise Systems Connections) is a method of data connection proprietary to IBM. The method utilizes a half-duplex optical fiber with serial interface. It is used mainly for connecting peripheral devices (printers, tape drives, disk storages) to IBM's mainframe computers. PacketLight's solutions support ESCON based connectivity.


Ethernet is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, longer link distances, and retains significant backward compatibility.



Forward error correction (FEC) refers to an error-controlling mechanism in data transmission. FEC allows the sender to add redundant data to the transmitted information, aiding the receiver to identify and correct any errors in the data. FEC boosts the network optical performance by a factor of at least 4 (6dB coding gain), and is a major feature of the OTN network. It is standardized by both ITU-T G.709 and ITU-T G.975 specifications.

Fibre Channel (FC)

Fibre Channel (FC) is a standardized gigabit transport technology utilized in storage devices and storage networking. FC transport rates include 1/2/4/8/10/16/32G. PacketLight supports all these rates over long distances.


FICON (fiber connection) is a proprietary IBM Fibre Channel protocol used primarily in mainframe computers. PacketLight products support FICON FC protocol.


Federal Information Processing Standards (FIPS) were developed by the US federal government for use in computer systems by non-military government agencies and government contractors. One of the main topics of the FIPS standards is computer security. PacketLight encryption devices are certified with FIPS 140-2 Level 2 requirements for encryption and data security.



The General Data Protection Regulation ((EU) 2016/679), is designed to strengthen and unify data protection for all individuals within the EU, including export of personal information outside the EU. The GDPR stipulates that businesses must receive consent from individuals to collect personal details, and this consent can be withdrawn at any given time, with the information permanently deleted. The GDPR includes small to medium enterprises (SME) and large businesses. It took effect in May 2018, replacing the 1995 data protection directive (Directive 95/46/EC).


Insertion Loss

Insertion loss of a component is one of the main factors influencing optical link budget. It is expressed in dB and defined as 10*log (Pout/Pin of a signal of an optical component), where Pout = Signal Power at Output, and Pin = Signal Power at Input. Optical amplifiers are typically used to compensate for insertion losses along the optical path.


International Telecommunication Union (ITU) is a part of the UN family responsible for managing communication and technology issues for world governments and corporate communities. ITU is best known for its activities in establishing standards for technology and telecommunication equipment, monitoring the international radio-frequency spectrum, and spreading the technology around the world. ITU standards are recognized worldwide. PacketLight is on the ITU-approved telecom equipment list.



L-band in optical networking refers to a section of wavelengths (colors) of light that ranges between 1565nm to 1625nm.


A local area network (LAN) is a group of devices that share a common communications line. The LAN network is usually concentrated in a relatively small area such as a single room, building or group of buildings.


Latency in optical networking refers to the time it takes for a signal to reach from the start point to the end point. This timeframe is usually measured in milliseconds and is especially important in applications that require speedy transfer of information such asvideo streeming and financial transactions.

Layer-1, Layer-2, Layer-3

In fiber optic networks, networking standards are separated into layers:
Layer-1 - the physical layer - electrical and optical hardware where the electrical signals are converted into light, so they can be transported over fibers for short distances inside the data center or over long haul DWDM optical networks.
Layer-2 - the data link layer - handles errors in the physical layer, provides flow control, and frame synchronization.
Layer-3 - the network layer - switching and routing data from node to node.

LR4 (100GBASE-LR4)

100GBASE-LR4 refers to 100Gb Ethernet. It is a port type for long range (LR) optic for single mode fiber. It uses 4 wavelengths in the 1300nm, each carrying 25G over a distance of 10km, with the mux/demux built-in to the modules. The LR4 optical modules also support 100G OTN OTU4 rate.


Mesh Network

Mesh network is a network topology in which some or all the network nodes are connected directly with no dependency on a single node. The nodes are connected to as many other nodes as possible and work in cooperation to efficiently route data to and from clients, with every node participating in the relay of information. Mesh topology increases network resilience in case of a failure of a node or connection.

Metro Ethernet

Metro Ethernet is an Ethernet-based standard often used to connect branch offices and other homogeneous organizations to internal Internet (Intranet). The Metro Ethernet computer network covers a large metropolitan area in order to connect users and businesses to the Internet.

Multimode (MM) Fiber

Multimode fiber has a larger diameter core for light path than single mode fiber. In multimode fiber, light propagates in multiple modes, each taking a slightly different path through the fiber and travelling at a slightly different velocity for a given fiber length. The multimode optical light source is based on low cost LEDs and electronics, making multimode fiber networks a much more cost-effective optical connectivity solution. However, the low light concentration makes this solution applicable for short distances of between 300m and 550m. PacketLight’s WDM solutions enable to extend multimode fiber capabilities beyond the 550m limitations of the 62.5µm (OM1) multimode fiber, to 2km or more depending on fiber quality and service type.

Multiplexer (Mux)

A multiplexer (mux) is an electronic device that combines multiple electronic input signals into a single output signal, while maintaining the integrity of each signal. In optical networks, multiplexers unite different data rates coded in different colors, into one signal that can be transported over single or dual fiber without degrading or altering the signals.


In WDM networks, muxponder technology aggregates multiple services into a single wavelength and then multiplexes them with other wavelengths into the same fiber. WDM technology increases fiber capacity by multiplexing multiple wavelengths with a dedicated service (GbE/10/40/100GbE LAN, SONET/SDH, Fibre Channel, HD/SD-SDI, OTU2/3, etc.) into a single fiber optic cable.


Native Video Transport

Video is typically transported over metro networks. For example, live feeds to a TV studio, or within campus and enterprise networks. Native broadcast video transport transport delivers high quality video without compression, with low latency and reduced cost. Native video transport applications includes broadcast studios, sports stadiums, digital production and broadcast facilities and stations (TV, cinema). Video interfaces include 3G HD-SDI, HD-SDI, SD-SDI, DVB-ASI, FE/GbE, FC/FICON, SONET/SDH.


Next Generation Networking (NGN) is a term commonly used to describe packing voice, data, and video information into the same data packets using OTN encapsulation. NGN architecture is constantly evolving in the fields of telecommunication and access. PacketLight solutions support NGN architecture and serve as a basis for developing its infrastructure.



An optical add-drop multiplexer (OADM) is a passive optical device used in WDM networks and enables to add and separate (drop) single or multiple wavelengths (channels) from a stream of light on a single fiber while the remaining wavelengths continue through to the their destination.


OpenROADM is an interoperability specification for the 400G DWDM pluggable module, defined by multi-source agreement (MSA). It focuses on long reach (>120km), advanced forward error correction (Open FEC) and supports 100G, 200G, 300G, and 400G data rates.


OpenZR+ is a merge of two standards: ZR (by OIF) and OpenROADM (by MSA), which combines the best features from each standard and enables high performance pluggable modules and multi-vendor interoperability. The target reach of the OpenZR+ standard is 1200km. More than 10 times the reach of 400ZR.

Optical Amplifier

An optical amplifier amplifies the optical signal without first converting it to an electrical signal. Amplifiers are important in fiber optic systems as they eliminate the need for repeaters in long haul networks, which may include several amplification sites along the link. Optical amplifiers can amplify the entire C-band spectrum (up to 96 wavelengths) simultaneously. PacketLight offers the two main types of optical amplifiers: Erbium-doped fiber amplifier (EDFA), and Raman amplifiers.

Optical Carrier (OC)

Optical carrier (OC) transmission rates are standardized specifications of transmission bandwidth for digital signals that can be carried on synchronous optical networking (SONET) networks. There are several levels of OC: OC-1, OC-3, OC-12, OC-24, OC-48, OC-192.

Optical Transmitter

An optical transmitter is a device that sends data and information to a receiver through a fiber optic cable. A transmitter is usually connected to a power supply and is part of an active solution for fiber optic networks.


The optical supervisory channel (OSC) is an additional wavelength which is usually outside the EDFA (see above) band, which carries information about the optical signal as well as remote conditions at the optical terminal or EDFA site. It is also normally used for remote software upgrades and user network management information.


Optical transport network (OTN) is an optical mapping layer for a number of different services over the same common frame and rate structure, enabling a single optical transport network regardless of the native client signal. OTN relies on ITU-T G.709 digital wrapper specification to transparently encapsulate client signals and provide faster troubleshooting and superior SLA monitoring capabilities. OTN includes the additional benefit of forward error correction (FEC) to boost the network optical performance by a factor of at least 4 (6dB coding gain).


OTU4 is an OTN rate that transports a 100Gb Ethernet signal. It is defined in the ITU-T G.709 standard.


Point-to-point Network

A point-to-point network topology refers to a bi-directional connection between two endpoints or nodes.



Quad small form factor pluggable (QSFP) is an optical transceiver usually used for 40G links in data centers, and is often used to save panel space by replacing 4 x SFP+.The optical and electrical interfaces utilize 4 lanes of 10G. The optical interface can be 4 lanes over a single fiber (single mode) or 4 lanes over 4 fibers (multimode). QSFP+ supports short reach (SR), long reach (LR) and extender reach (ER), with each providing a cost/reach tradeoff.


Quad small form factor pluggable 28 (QSFP28) is a hot-pluggable transceiver module designed for 100G data rate. It integrates 4 transmitter and 4 receiver channels. "28" refers to each lane carrying up to 28G data rate. Depending on the transceiver used, the QSFP28 typically operates at 4x25G for 100GbE but it will evolve to 2x50G or 1x100G over time as technology progresses. The QSFP28 has the same mechanical footprint and host board connector designs as the QSFP+ optical module, so it also supports 40GbE or breakout into 4x10GbE. There are three main types of QSFP28: LR4 for 10km, SR4 for 100m, and CWDM4 for 2km. The small footprint and low power consumption of the QSFP28 enable high density and capacity in 1U optical and switching systems, which facilitates cost reduction.


The quad small form factor hot pluggable (QSFP) double density (DD) transceiver module is designed for 400G data rate. It integrates 8 transmitter and 8 receiver electrical channels. DD means the doubling of the number of high-speed electrical interfaces that the module supports compared with a standard QSFP28 module. Each lane carries 50Gb/s by PAM4 modulation technology, achieving 400G network transmission, suitable for high-performance computing data centers and cloud networks. Depending on the transceiver used, the QSFP-DD typically operates at 8x25G NRZ modulation for 200GbE or 8x50G PAM4 modulation. The QSFP-DD has a similar mechanical footprint to the QSFP28, but the host board connector design is different (double the number of pins). The main QSFP-DD types are: CDWM LR4 for 10km, SR8 for 100m (MMF), DR4 for 500m and CWDM FR4 for 2km.


Raman Amplifier

Raman amplification is achieved by nonlinear interaction between the signal and a pump laser within an optical fiber. The Raman pump power is higher than in the Erbium-doped fiber amplifier (EDFA), enabling the signal to travel further (between 200km and 300km, depending on fiber attenuation). The Raman amplifier increases the effective distance and significantly improves OSNR.


A reconfigurable optical add-drop multiplexer (ROADM) is an optical device that allows wavelengths to be added or dropped from a WDM transport network without first converting them into electrical signals. The ROADM is remotely configurable and allows automatic power balancing.


Single Mode (SM) Fiber

There are two types of fibers in optical networking today: single mode and multimode. Single mode (SM) optical fiber has a smaller core diameter, which forces all the energy in a light signal to travel in the form of a single mode, dramatically increasing the bit rate over distance. As it has a laser-based light source, SM fiber requires more expensive and precise electronics for data transport.


Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized multiplexing protocols that transfer multiple streams of bit over the optical fiber. SONET is the standard used in the US and Canada, and SDH is the standard used in the rest of the world. SONET rates are designated by optical carrier (OC), OC-1/3/12/24/48/192. SDH rates are designated by synchronous transport module (STM) STM-1/4/16/64.

SR10 (100GBASE-SR10)

100GBASE-SR10 refers to 100Gb Ethernet. It is a port type of short range (SR) optics for multimode fiber. It uses 10 fibers, carrying 10Gb/s each for a distance of up to 100m. It is used inside data centers, typically in the same rack. PacketLight SR10 modules support OTN OTU4 100G (although rarely required for this application).


Synchronous transport module (STM) is the standard for transmitting SDH signal over fiber optic network. There are several levels of STM: STM-1, STM-4, STM-16 and STM-64.

Storage Area Network (SAN)

A storage area network (SAN) is a system of storage devices incorporated into a one data storage unit and transparently connected to the local area network (LAN). It can usually be accessed only by a system administrator.



Optical transponders send and receive the optical signal from a fiber. A transponder is typically characterized by its data rate and the maximum distance the signal travels. Transponders convert the incoming optical signal into a pre-defined optical wavelength, by first converting it to an electrical signal and performing the 3R. The electrical signal then drives the laser, generating the optical signals. Transparent transponders implement 3R functionality for shorter distances of up to 200km, and OTN transponders add the encapsulation of the service into OTN with FEC, enabling the signal to transport over thousands of kilometers without the need for regenerators.



Wavelength division multiplexing (WDM) is a technology of optical networking used to combine multiple optical signals into one, and transfer it over a single fiber, using multiplexing and demultiplexing to achieve the desired effect. WDM technology increases capacity while significantly decreasing CAPEX and OPEX of optical networking. It also enables bi-directional communication. There are two types of WDM technology: coarse WDM (CWDM) and dense WDM (DWDM).