Fiber optic connector that comes in various configurations and types is considered as an important component for the fiber optic cable. Generally speaking, different fiber cable connector types can be categorized according to different standards like the utilization, fiber count, fiber mode, transmission method, the transmission media, the boot length, the polishing type and the termination way, etc. Follow this article to classify fiber connector types.
The following fiber connector types, such as LC/SC/MTP/MPO/ST fiber optic connectors, require an adapter panel when connecting. Fiber cables with these optical connector types are usually used in data centers, telecom rooms, enterprise networks and so on.
A Lucent Connector (LC), as one SFF (small form factor) connector, possesses a 1.25 mm ferrule. The small footprint design gives these fiber optic connectors huge popularity in datacoms and makes them more ideal for high-density applications. Many tend to move to high-efficiency cabling with LC fiber connectors nowadays. LC fiber optic connector is considered the most commonly-used connector at present.
SC fiber connector was the first connector chosen for the TIA-568 standard and is a snap-in connector that latches with a simple push-pull motion. "SC" stands for "Square Connector" due to the "square-shaped" connector body. It adopts a 2.5mm ferrule, which is twice the size of the previous LC connector. SC fiber optic connector is ideally suited for datacoms and telecom applications including point to point and passive optical networking. Due to its excellent performance, fiber optic SC connector remains the second most common connector for polarization maintaining applications.
Unlike the previous two fiber optic conneceors, the MTP/MPO fiber connector is a multi-fiber connector and larger than other connectors, which combines fibers from 12 to 24 fibers in a single rectangular ferrule. It's often used in 40G and 100G high-bandwidth optical parallel connections. The MTP/MPO fiber connectors are complicated due to the key-up and key-down, male and female issues. You can refer to our white paper Understanding Polarity in MTP/MPO System to have a better understanding.
ST (Straight Tip) fiber optic connector was created and licensed by AT&T shortly after the arrival of the FC type. The ST optic connector holds the fiber with a ceramic, spring-loaded 2.5mm ferrule that stays in place with a half-twist bayonet mount. They are usually used in both long and short distance applications such as campuses and building multimode fiber applications, corporate network environments, as well as military applications.
"FC" refers to the Ferrule Connector. FC fiber optic connector was the first optical fiber connector to use a ceramic ferrule. Unlike the plastic-bodied SC and LC connector, it utilizes a round screw-type fitment made from nickel-plated or stainless steel. The FC fiber optic connector end face relies on an alignment key for correct insertion and is then tightened into the adaptor/jack using a threaded collet. Despite the additional complexity both in manufacturing and installation, the FC connectors still provide the choice in precision instruments such as OTDRs, as well as the choice for single mode fiber. It was initially intended for datacoms and telecoms applications but was used less since the introduction of the SC and LC fiber optic connectors. The usage of both ST and FC connectors have declined in recent years.
The abovementioned five fiber optic connectors are the most commonly used ones, which are introduced based on their popularities from wide to usual. The figure below shows the different connector style:
Figure1: LC vs SC vs MTP vs ST vs FC Connector
Mechanical Transfer Registered Jack (MT-RJ) connector is a duplex connector that uses pins for alignment and has male and female versions. Constructed with plastic housing and provide for accurate alignment via their metal guide pins and plastic ferrules. Compared to a standard phone jack, the size of MT-RJ connector is slightly smaller, making it easier to connect and disconnect. In addition, MT-RJ fiber optic connector provides a lower termination cost and greater density for both electronics and cable management hardware compared to other singer-fiber terminations.
Like a miniature SC with a 1.25mm ferrule. Featuring a simple push-pull design and compact miniature body, the MU fiber optic connector is used for compact multiple optical connectors and a self-retentive mechanism for backplane applications. You can get a customized high power MT-RJ/MU fiber optic connector in FS.
The DIN connector is round with pins arranged in a circular pattern. It encompasses several types of cables that plug into an interface to connect devices. Typically, a full-sized DIN connector has three to 14 pins with a diameter of 13.2 millimeters. It is applied for PC keyboards, MIDI instruments, and other specialized equipment.
The E2000 Connector is a push-pull coupling mechanism with an automatic metal shutter in the connector as dust and laser beam protection. One-piece design for easy and quick termination, E2000 fiber optic connector is used for high safety and high power applications.
Compared to the above fiber optic connector types, Rosenberger Q-RMC and NEX10 connector adopt push-pull quick locking mechanism, which can realize quicker connection without using an adapter panel. They are designed for harsh environment use.
Q-RMC, short for Rosenberger Multifiber Connector, is a new and robust industrial connector with the multi-fiber MT ferrule of the MTP®/MPO connector that can hold 24 fiber cores. This kind of very small form factor connector includes a push-pull closing mechanism, which makes the optic connector to be connected simpler and quicker even in tight areas, thus reducing installation times and the associated costs. The Q-RMC connector fulfills the requirements for protection class IP67, so it is waterproof, dustproof and resistant to corrosion. What's more, the Q-RMC connector is suitable for use in areas with extreme temperatures thanks to its' operating and storage temperature is up to -40~80℃. So, fiber cables with Q-RMC connector can be used for industrial site, mine field, mobile communication (FTTA), 5G Base Station, broadcast, smart grid cabling and so on.
The Rosenberger NEX10 connector is suitable for an outdoor harsh environment, and it is characterized by compact size design plus waterproof, dustproof and anti-corrosion. This connector type supports screw-type and a push-pull locking mechanism. The push-pull quick lock helps in achieving solid installation and easy removal without any tools. For the screw type plug, there is a screw-locking mechanism, ideal for the plug and socket keeps firm connection. Nowadays, FS introduces the industrial fiber optic patch cable with Rosenberger NEX10 connector, and its' operating & storage temperature for connectors & outdoor cables lie between -40~80℃, which is often used in industrial site, Mine field, small sells, distributed antenna systems(DAS), In-building architecture, and MIMO.
Figure2: Rosenberger Q-RMC and NEX10 Connector
Both single mode and multimode Q-RMC/NEX10 connectors are available in FS. And you can also choose optical fiber type, cable jacket according to your needs to get a customized industrial fiber optic cable.
A simplex connection means signals are sent in one direction—a signal is transmitted through two simplex connectors and a simplex fiber cable from device A to device B, which cannot return from device B to device A via the same route. Contrariwise, the revised transmission can be achieved through duplex connectors and duplex fiber cable, which is called a duplex connection. In addition, a simplex fiber optic connector is often connected with one strand of glass or plastic fiber, while the duplex fiber optic connector needs to connect with two strands of fibers.
Figure3: Simplex vs Duplex Fiber Connector
Single mode fiber allows only one light mode to pass through at a time, while multimode fiber can propagate multiple modes at a time. Diversity has an impact on single mode fiber connectors and multimode fiber connectors on account of the combination with the corresponding type of optical fibers. However, with technologies getting advanced, fiber optic connectors like SC, LC, and FC, provided by fiber optic connector factories are compatible with single mode and multimode fiber cables.
As for the boot length, there are standard boot structure and short boot structure. A standard boot can protect the cable and the connector from being damaged, wires being dislodged from the connector body, etc. While a short boot has the same function, it is distinguished by a shorter boot structure. For places where there is limited space for connector, short boot cables can be the ideal choice. The short boot structure design can make the cable easily pass through the narrow space without sacrificing performance, making the installation and maintenance of the fiber optic cables more efficient.
Figure4: Short Boot vs Standard Boot
According to the polishing type, optical fiber cable connectors can be divided into three types: PC, UPC, and APC connectors. The color code provides a convenient method to identify these three types of connectors: PC's color code is black, the color code for the APC fiber connector is green, and the UPC's connector is blue. The structure and the performance of the three fiber optic connectors also vary, which reflects on the values of insertion loss and return loss. PC vs UPC vs APC, this article shed light on these connector types and their differences for you.
Figure5: PC vs UPC vs APC Connector
Field termination, as its name implies, is to terminate the end of the fiber in the field. The procedure includes strip the cable, prep the epoxy, apply the connector, polish, inspect and test for the connection, requiring not only a large number of tools but also skilled technicians to conduct the termination.
Factory termination, also called factory pre-termination, refers to cables and fibers terminated with a connector in the factory. The pre-terminated cables come in pre-measured lengths with the fiber optic connectors already installed with factory-level precision and quality assurance. Reducing the cumbersome process and tools, factory pre-terminated solutions are easier to install and require less technical skills.
Do single mode connectors work on multimode cables?
Yes. you can use single mode connectors on multimode, but not the other way around.
If I have an SC connector installed and find that what I need is LC type, how can I do?
In this kind of situation, a common solution is that you can purchase an SC-SC coupler, then purchase a pre-terminated SC to LC patch cable. Adapters are also available like LC-LC or LC-SC.
What types of fiber optic connectors are available on the market?
The common types of fiber optic connectors are LC, SC, MTP/MPO, ST, and FC. LC connector, as a main fiber optic connector, tends to be the most preferred one due to its compact size, high performance, and ease of use. In addition, for multi-fiber connectors, the MTP/MPO connectors are also gaining popularity for 40G and 100G data transmissions.
Fiber optic connectors are engineered to provide perfect alignment of the microscopic glass fibers used in fiber cables to transmit data. These sort of connections have to be highly precise in order to facilitate high speed fiber optic networking. This chart helps to identify some of the many fiber optic connector types available on the market today.
ST connectors were one of the first connector types to be broadly executed in fiber optic networking applications. The ST, or "Straight Tip" connector, was created by AT&T. The connector makes use of a 2.5mm ferrule. Because they all have the same ferrule size, the ST can be mixed and matched with FC, SC, FDDI, and ESON connectors using a hybrid adaptor. The connector stays in place with the help of a half twist bayonet style lock.
The ST connector is typically found on the end of a multi-mode cable, but this connector is gradually being replaced with multi-fiber connectors (LC and MTP). ST connectors can be plugged and unplugged from fiber optic cables easily and quickly. Typical insertion loss from matching ST connectors is 0.25dB.
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SC connectors are snap-in connectors that were developed in Japan by an indigenous telecommunications company called NTT. The SC is believed to stand for "Subscriber Connector" or "Standard Connector". This connector can be utilized with singlemode and multimode fiber optic cables. Just as with ST Connectors, multi-fiber connectors are gradually replacing SC connectors in fiber optic communications.
The SC connector uses a 2.5mm ferrule and latches with a push-pull mechanism that offers quick insertion and removal. SC connectors are generally easier to use in tight spaces, as compared to the twist-style ST connectors. Two square-shaped SC connectors are commonly bound together with a plastic clip, creating a duplex connection. SC connectors are relatively low cost, simple and durable. Matching SC connectors have an insertion loss of 0.25dB.
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Developed by Lucent Technologies, the LC connector or Lucent Connector, measures about half the size of an SC connector. LC connectors are used for high density deployments where multiple fibers terminate within a confined space. A small form factor connector, the LC connector uses a 1.25mm ferrule with a retaining tab mechanism that is similar to that of a phone or RJ-45 connector.
Just as with SC connectors, the body of a LC connector is square shaped, and two LC connectors are commonly bound together with a plastic clip to create a duplex connection. LC connectors can be used with both singlemode and multimode cables. Matching LC connectors have an insertion loss of 0.25dB.
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The first 10G copper standard to be published was the 10G-CX4. The 10G-CX4 connector offers low cost, low power and low latency. However, it is a larger form factor that uses bulkier cables than modern single-lane SFP+ standard connectors.
Copper cables that utilize the 10G-CX4 connector have a much shorter reach (up to 15 meters) as compared to fiber or 10GBASE-T cables.
The 4x connector is named for its ability to support 4 aggregated data links. Because this type of fiber optic connector is commonly used on Infiniband cables, it has become known as the "Infiniband Connector".
Infiniband is a high-bandwidth I/O communication technology that is typically deployed in high performance computing applications, server clusters and data centers. While Infiniband cables appear identical to 10G-CX4 cables, Infiniband cables cannot be used in 10G-CX4 applications.
The Mechanical Transfer-Registered Jack (MTRJ) connector was created by AMP/Tyco and Corning. The MTRJ is a duplex connector that looks similar to the RJ-style modular. It uses a tabular locking mechanism and has a plastic body and ferrule. The ferrule technology used in MTRJ connectors is the same as that used for Multi-fiber Termination Push-on (MTP) connectors.
There are both male and female versions of the MTRJ connector, which uses pins for alignment. MTRJs are also available in both singlemode and multimode tolerances. Matched MTRJ connectors have a 0.25dB insertion loss for singlemode fiber and 0.35dB loss for multimode fiber.
The MTP connector, manufactured by US Conec, is an improvement on the NTT designed MPO connector. The MTP connector terminates up to 12 strands of fiber in one ferrule and locks in place with a push-on/pull-off latch. A pair of metal guide pins protrude from the front of the connector.
Both singlemode and multimode cables may be used with MTP/MPO connectors. Singlemode MTP/MPO connectors have an angled ferrule for minimal reflection. Multimode MTP/MPO connectors have a flat ferrule. MTP/MPO assemblies are mainly used in breakout, cross-connect and backbone applications.
Matched MTP/MPO connectors have a typical loss insertion of 0.25dB.
The RJ-45, or "Registered Jack-45" connector, is an eight-wire connector that is mostly used to connect Ethernet LANs devices. RJ-45 connectors look like larger versions of the older RJ11 connectors, which are used on wired telephones. In cable assemblies, RJ-45 connectors are not fiber optic connectors. Rather, they are the standard connector for CATx Ethernet cables, which are used to connect a network switch to a patch panel and/or for connecting a computer’s network interface controller to a data port.
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The D4 connector has a 2.0mm ferrule and uses a screw-on mechanism. It's an older generation connector that is spring loaded and keyed. The key prevents opposing ferrule end-points from rubbing together while mating. Due to its modest size, many D4 connectors can be loaded into a single fiber distribution frame.
The NEC specified the D4 connector and used it on all of their equipment interfaces. The NEC D4 was likely the very first connector to utilize hybrid ceramic/stainless or ceramic steel ferrules. It was extensively used in telecommunications networks in the late '80s and early '90s, and some may still be in use today.
IBM created the Enterprise Systems Connection (ESCON) in the early '90s to connect their main-frame computers to other external devices, like tape drives and disk storage drives. The ESCON connector is an optical fiber, serial interface, half-duplex connector. It uses a 2.5mm ferrule and can be mated to ST and SC connectors using adapters. Today, ESCON connectors have largely been superseded by substantially faster fiber channel connectors (FICON).
The Panduit Opti-Jack is a solid duplex connector that utilizes two duplex SC ceramic ferrules, each 2.5mm in diameter. The ferrules are independently spring-loaded and are aligned using conventional split-sleeve mechanical techniques.
The Opti-Jack is the size of an RJ-45 connector and is available in both male and female (plug and jack) variants. The connector's latch is modeled after the industry standard RJ-45 wall jack. It supports adapters, couplers, and conventional duplex jumper cables, although Opti-jack transceivers aren't broadly accessible.
An FDDI, or Fiber Distributed Data Interface, is a local area network standard used to transmit data. The point at which the fiber optic cables terminate is the FDDI connector, also referred to as a MIC (Media Interface Connector). An FDDI connector contains two ferrules that are housed in a large plastic container that uses a squeeze-tab retention mechanism. Using adapters, FDDI connectors can be mated to SC or ST connectors.
FDDI provides an optical standard of 100 Mbit/s for data transmission. It can be used in a local area network, extended up to 200 kilometers (120mi), and supports thousands of users.
An MU, or Multi-termination Unibody connector, looks like a miniature version of the SC connector. MU connectors are a type of SFF connector manufactured by NTT. They are more popular in Japan than they are in the United States.
MUs have a ceramic ferrule of just 1.25mm in diameter, which is about half the size of a standard SC connector ferrule. Zirconia split-sleeves with smaller diameters support adapters, duplex couplers, and similar jumper cable applications.
MUs use a self-retention mechanism that is similar in design to a push-pull SC latch, which allows for blind mating inside a printed circuit board backplane. It is not yet possible to purchase transceivers with an MU interface, although some development work has been started in this area.
The arrival of 200G and 400G transceivers in the latest generation of data centers created demand for higher density optical jumper connectivity than could be achieved with the existing LC type connectors. The new “CS” connector is designed or these next generation 200G/400G QSFP-DD and OSFP transcievers in mind. The following is a list of features of this new connector:
The CS® connector is operated with push-pull coupling mechanism has two cylindrical, spring-loaded butting 1.25mm ferrules, within a single housing. The CS® connector’s two ferrules are pitched at 3.8mm apart, which is the minimum possible spacing to meet the TOSA and ROSA optics requirement. Furthermore, CS® has an advantage in height over LC connector. The LC’s latching lever design requires adequate vertical spacing between adapters to get physical access to the release lever. The CS® connector comes with push pull tab which allows the adapters to be more densely stacked vertically. CS® can more than double the density in the patch panel compared to LC, with the features of narrower adapter width and denser vertical stacking of the CS® adapter.
SN Connector is a next generation connector designed by SENKO Advanced Components. This new duplex connector is optimized for 400G transceivers, is an alternative solution for the next generation high density Data Center. Key features of the SN connector are:
The SN® Standard connector is suitable for termination to either 1.6 mm or 2.0 mm round cable that incorporates a ruggedized jacket and internal strain relief. The SN® Standard connector has an integrated ‘push-pull’ boot that simplifies insertion and removal of the connector even in dense patch panels where finger access is limited. A gang-clip can be added to four individual SN® connectors allowing them to be patched simultaneously to either adapters or 4-channel (8 fibers) transceivers (subject to product selection).