Fiber Optic PC Connectors: Single-channel vs. Multi-channel

Over the past 30 years, fiber optic technology has spanned its commitment constantly with the even more endeavors nowadays to meet the ever-increasing networking bandwidth for high-quality Internet applications. In these applications, fiber optic connectors, serving as mousetraps, are used to couple the source, receiver and other components to the fiber optic cable. Fiber optic connectors generally use either physical contact (PC) or expanded beam technology. This article mainly discusses PC connectors from single-channel and multi-channel aspects.

It’s necessary to figure out what PC connections are first.

What Are PC Connection?

A PC connection is accomplished by terminating the optical fiber into a precise ceramic ferrule. The tip of the ceramic ferrule is polished in a precise manner to ensure that light enters and exits at a known trajectory with little scattering or optical loss. In achieving PC connection, there are two requirements for a cleaved fiber endface for PC connection. One is that the fiber endface inclination is less than 0.6°, and the other is that there is no mist on the endface.

PC Connector Types

There are countless single-channel and multi-channel fiber optic PC connector types available for telecommunication and data-communication industries.

Single-channel Connectors

PC connectors are characteristic of directly mating and polishing fibers by utilizing tight tolerance ferrules and alignment sleeves and/or mating pins. This ceramic-ferruled technology permits reliable optical performance, with several designs becoming widely used as industry standards. Typically, these connectors are single fiber solutions with plastic shells. FC and ST connectors are becoming less popular but are still used in instrumentation. LC and SC connectors are commonly used in the telecommunication industry.

As a push-pull connector, LC connector, licensed by Lucent Technologies, provides a pull-proof design and small size perfect for high-density applications. It’s available in simplex or duplex versions, widely used in 10Gigabit, 40Gigabit and 100Gigabit applications. Like Cisco QSFP-40GE-LR4 transceiver, QSFP-40GE-LR4 listed on Fiberstore establishes 40Gigabit Ethernet (GbE) links with this duplex LC connector for 10km maximum link length over single-mode fiber (SMF).

SC connector, developed by Nippon Telegraph and Telephone (NTT), is recommended in the TIA/EIA-568-A Standard for structured cabling. It’s also available in simplex or duplex versions, typically used in Analog CATV (Cable Television) and other telecoms applications including point to point and passive optical networking.

Multi-channel Connectors

Multi-channel connectors house multiple fiber optic termini in a precision insertion. The termini can be configured as a pin/socket combination or genderless. MTP/MPO connectors belong to PC multi-channel connector.

The US CONEC MTP is a MPO compatible connector that exhibits quick and reliable connections for up to 12 fibers in a very small form factor. Just like LC connector, 40G links are likely to deploy this kind of MPO-12 connector for high performance. Take Cisco QSFP-40G-CSR4 for example, this QSFP-40G-CSR4 transceiver sets up 40G links in 850nm multi-mode fiber (MMF), with MPO-12 as its connector.

Optical Performance

Both single-channel and multi-channel PC connectors have optical performance characterized by return loss. The return loss of the connector is a measurement of how much light is reflected back at the connector interface. It’s affected by alignment, contamination and polishing. For example, if the mating faces of the two fibers are not parallel, some energy reflects back to the source. Additionally, contamination at the mating interface causes reflection and scattering of light. What’s more, a poor polish may create an end-gap separation or an end-angle.

Featuring by the tightest tolerance ceramic ferrules and alignment sleeves, coupled with the highest quality termination and polishing procedures, PC connections are able to deliver unrivaled optical performance.

Conclusion

Fiber optic connectors make quick fiber connection and efficient light transmission possible, gaining more and more popularity among their users. Fiberstore offers hundreds of fiber optic connectors, such as FC, D4, DIN, MU, the MTP/MPO ST, SC and LC, as well as their related optic modules (eg. QSFP-40GE-LR4 and QSFP-40G-CSR4 mentioned above). You can visit Fiberstore for more information about fiber optic connectors.

LC Connector Family

The LC connector developed by Lucent Technologies and shown in Fig.3.10 is a more evolutionary approach to achieving the goals of a SFF connector. The LC connector utilizes the traditional components of a SC duplex connector having independent ceramic ferrules and housings, with the overall size scaled down by one-half. The LC family of connectors includes a stand-alone simplex design; a “behind the wall” (BTW) connector and the duplex connector available in both single-mode and multimode tolerances are all designed using the RJ-style latch.

The outward appearance and physical size of the LC connector varies slightly depending on the application and vendor preference. Although all the connectors in the LC family have similar latch styles modeled after the copper RJ latch, the simplex version of the connector has a slightly longer body than either the duplex or BTW version, and the latch has an additional latch actuator arm that is designed to assist in plugging as well to prevent snagging in the field. The BTW connector is the smallest of the LC family and is designed as a field-or board-mounatable connector using 900-um buffered fiber and in some cases has slightly extended latch for extraction purposes. The duplex version of this connector has modified body to accept the duplexing clip that joins the two connector bodies toghther and actuates the two latches as one. Finally, even the duplex clip itself has variations depending on the vendor. In some cases the duplex clip us a solid one-piece design and must be placed on the cable prior to connectorization, while other design and must be placed on the cable prior to connectorization, while other designs have slots built into each side to allow the clip to be installed after connectorzation. In coclusion, all LC connectors are not created equal, and depending on style and manufacturer’s preference, there may be attributes that make one connector more suitable for a specific application then another.

The LC duplex connector incorporates two round ceramic ferrules with outer diameters of 1.25mm and a duplex pitch of 6.25mm. These ferrules are aligned through the traditional couplers and bores using precision ceramic split or solid sleeves. In an attempt to improve the optical performance to better than 0.10 db at these interfaces, most of the ferrule and backbane assemblies are designed to allow the cable manufacturer to tune them. Tuning of the LC connector simply consists of roating the ferrule to one of four available positions dictated by the backbone design. The concept is basically to align the concentricity offset of each ferrule to a single quadrant at 12.00; in effect, if all the cores are slightly offset in the same direction, the probalility of a core-to-core alignment is increased and optimum performance can be achieved. Although this concept has its merits, it is yet another costly step in the manufacturing process, and in the case where a tuned connector is mated with an untuned connector, the increase in performance may not be realized.

Typically, the LC duplex connectors are terminated onto a new reduced-size zipcord referred to as mini-zip. However, as the product matures and the applications expand, it may be found on a number of different cordages. The mini-zip cord is one of the smallest in the industry with an outer diameter of 1.6mm compared with the standard zipcord for an SC style product of 3.0 mm. Although this cable has passed industry standard testing, the cable manufacturers have raised some issues concering the ability of the 900-um fibers to move freely inside a 1.6-mm jacket and others involving the overall crimped pull strengths. For these reasons, some end users and calbe manufactures are opting for a larger 2.0-mm, 2.4-mm, or even the standard 3.0-mm zipcord. In application wher the fiber is either protected within a wall outlet or cabinet, the BTW connector is used and terminated directly onto the 900-um buffers with no jacket protection.

The factory termination of the LC cable assemblies is very similar to order ceramic-based ferrules using the standard pot and polish processes with a few minor differences. The one-piece design of the connector minimizes production handling and helps to increase process yields when compared with other SFF and standard connector types. Because of the smaller diameter ferrule, the polishing times for an LC ferrule may be slightly lower than the standard 2.5-mm connectors, but the real production advantage is realized in teh increase number of connectors that can be polished at one time in a mass polisher. For the reasons mentioned above and because the process is familiar to most manufacturers, the LC connector may be considered one of the eaisest SFF connectors to factory terminate.

Field termination of the LC connector has typically been accomplished through the standard pot and polish techiques using the BTW connector. However, a pre-polished, crimp and cleave connector is also available. The LCQuick Light field-mountable BTW style connector made by Lucent Technologies is a one-piece design with a factory polished ferrule and an internal cleaved fiber stub. Unlike other pre-polished SFF connectors previously discussed, the LCQuick light secures the inserted field cleaved fiber to a factory polished stub by crimping or collapsing the metallic entry tube onto the buffered portion. This is accomplished by using a special crimp tool that is designed not to damage the fibers. However, light is designed specifically for use in protected environments such as cabinets and wall outlets and has no provision for outer jacket or Kevlar protection.

LC connections allow higher density applications based on its smaller diameter. The LC connection, commonly referred to as Lucent Connection, Little Connector or Local Connector, is commonly used today for uplink modules and other devices. This connector is a “snap” type, has a ferrule diameter of 1.25mm and defined by IEC 61754-20. We offer LC fiber cables and lc lc cable, including single mode 9/125 and multimode 50/125, multimode 62.5/125, LC-LC, LC-SC, LC-ST, LC-MU, LC-MTRJ, LC-MPO, LC-MTP, LC-FC, OM1, OM2, OM3. Other types also available for custom design. Excellent quality and fast delivery.

The LC fiber patch cable cable is with a small form factor (SFF) connector and is ideal for high density applications. The LC fiber patch connector has a zirconia ceramic ferrule measuring 1.25mm O.D. with either a PC or APC end face, and provides optimum insertion and return loss. The LC fiber patch cable connector is used on small diameter mini-cordage (1.6mm/2.0mm) as well as 3.0mm cable. LC fiber cable connectors are available in cable assembled or one piece connectors. The LC fiber optic assemblies family is Telcordia, ANSI/EIA/TIA and IEC compliant.

Parsing Fiber Optic Connectors

The network cabling industry’s fiber optic manufacturers over the last few decades have been on a constant mission to develop the better fiber connector. This means lower cost, lower dB losses, easier to terminate out in the field. There have been over 100 connectors developed over the years but a select few have stood the test of time and beat out their competition. Now, let’s talk about the most common fiber connectors as following:

A fiber optic connector terminates at the end of a fiber optic cable is used when you need a means to connect and disconnect the fiber cable quickly. A fiber splice would be used in a more permanent application. the connectors provide a mechanical connection for the two fiber cables and align both cores precisely so the light can pass through with little loss. There are many different types of connectors but many share similar features. Many connectors are spring loaded. This will push the fiber ends very close other so as to eliminate airspace between them, which would result in higher dB losses.

There are generally five main components to a fiber connector: the ferrule, the body, the coupling structure, the boot and the dust cap.

Ferrule: The ferrule is the small round cylinder that actually makes contact with the glass and holds it in place. These are commonly made of ceramic today but also are made of metal and plastic.

Body: This sub assembly holds the ferrule in place. It then fits into the connector housing.

Connector Housing: This holds all sub assembly parts in place and has the coupling that will connect to the customer’s equipment. The securing mechanism is usually bayonet, snap-in or screw on type.

Boot: This will cover the transition from the connector to the fiber optic cable. Provides stress relief.

Dust Cap: Just as it implies will protect the connector from accumulating dust.

There are many types of connectors on the market. The major differences are the dimensions and the method of connection to equipment. Most companies will settle on one type of connector and keep that as a standard across the board. It makes sense because all equipment has to be ordered with that specific connector type and to have 2 or 3 different connector types can get messy. For typical network cabling projects today LC is fast becoming the shining star of fiber connectors. LC is a small form factor connector which means it requires a much smaller footprint in your IT closet. Thus you can fit many more LC connectors into you fiber panels then say ST or SC connectors.

LC Connector

The LC connector was developed by Lucent Technologies, hence the LC. It is a Single Form Factor Connector that has a 1.25mm ferrule. The attaching mechanism is similar to an RJ-45 connector with the retaining clip. It is a smaller square connector, similar to the SC. LC connectors are often held together with a duplex plastic retainer. They are also very common in single mode fiber applications.

ST Connector

The ST connector was the first popular connector type to be used as a standard for many organizations in their fiber network applications. It has first developed by AT&T. Often called the “round connector” it has a spring loaded twist bayonet mount with a 2.5mm round ferrule and a round body. The ST connector is fast being replaced with the smaller, denser SFF connectors.

SC Connector

The SC connector is a push in/pull-out type connector that also has a 2.5 mm ferrule. It is very popular for its excellent performance record. The SC connector was standardized in TIA-568-A, and has been very popular for the last 15 years or so. It took a while to surpass the ST because of price and the fact that users were comfortable with the ST. Now it’s much more competitive with pricing and it is very easy install, only requiring a push in and pull out connection. This is very helpful in tight spaces. Simplex and duplex SC connectors are available. The SC was developed by the Japanese and some say stands for Standard Connector.

FC Connector

The FC connector you may find in older single mode installations. It was a popular choice that has been replaced by mostly ST or SC type connectors. It also has a 2.5mm ferrule. They have a screw on retaining mechanism but you need to be sure the key and slot on the connector are aligned correctly. FC connectors can also be mated to ST & SC’s through the use of an adaptor.

MT-RJ Connector

MTRJ stands for Mechanical-Transfer Registered Jack and was developed by Amp/Tyco and Corning. MTRJ is very similar to an RJ type modular plug. The connector is always found in duplex form. The body assembly of the connector is usually made from plastic and clips and locks into place. There are small pins present that guide the fiber for correct alignment. MTRJ’s also are available in male or female orientation. They are only used for multi-mode applications. They can also be difficult to test because many testers on the market do not accept a direct connection. You usually need to rig up a patch cord adaptor kit to make testing possible.

MU Connector

MU looks a miniature SC with a 1.25 mm ferrule. It’s more popular in Japan.

MT Connector

MT is a 12 fiber connector for ribbon cable. It’s main use is for preterminated cable assemblies and cabling systems. Here is a 12 fiber MT broken out into 12 STs.

MT connector is sometimes called a MTP or MPO connector which are commercial names.

Hopefully this guide may help you get an idea of what options are out there for your fiber optic connector needs.

As the best Chinese fiber optic products supplier, FiberStore Inc. supply a range of fiber connectors, fiber attenuatorsfiber optic switch and more. If you would like to know more about our products information, please pay attention our news or contact us directly.

A comprehensive understanding of fiber optic connectors

Fiber connector has traditionally been the biggest concern in using fiber optic systems. While connectors were once unwiedy and difficult to use, connector manufacturers have standardized and simplified connectors greatly. This increases the user use convenient increase in the use of optical fiber systems; It is also emphasising taken proper care of and deal with the optical connector. This article covers connector basics including the parts of a fiber optic connector, installing fiber optic connectors, and the cleaning and handling of installed connectors. For information on connector loss, see Connector Loss Test Measurement.

Optical fiber to fiber optic interconnection can be made by a joint, a permanent connection, or a connector, and is different from the plug in it can be to disconnect and reconnect. Fiber optic connector types are as various as the applications for which they were developed. Different connector types have different characteristics, different advantages and disadvantages, and different performance parameters. But all connectors have the same four basic components.

The Ferrule

The fiber is installed in a long, thin cylinder, the ferrule, which act as a fiber alignment mechanism. The ferrule is bored through the center at a diameter that is slightly larger than the diameter of the fiber cladding. The end of the fiber is located at the end of the ferrule. Ferrules are typically made of metal or ceramic, but they may also be constructed of plastic.

The Connector Body

Also known as the connector housing, the body holds the ferrule. It is usually constructed of metal or plastic and includes one or more assembled pieces which hold the fiber in place. The details of these connector body assemblies vary among connectors, but the welding and/or crimping is commonly used to attach strength members and cable jackets to the connector body. The ferrule extends past the connector body to slip into the couping device.

The Cable

The cable is attached to the connector body. It acts as the point of entry for the fiber. Often, a strain relief boot is added over the junctioni between the cable and the connector body, providing extra stength to the junction.

The Coupling Device

Most fiber optic connectors do not use the male-female configuration common to electronic connectors. Instead, a coupling device such as an alignment sleeve is used to mate the connectors. Similar devices may be installed in fiber optic transmitters and receivers to allow these devices to be mated via a connector. These devices are also known as feed-through bulkhead adapters.

Table 1 illustrates some types of optical connectors and lists some specifications. Each connector type has strong points.

Table 1- Types Of Optical Connectors

Installing Fiber Optic Connectors

The method for attaching fiber optic connectors to optical fibers varies among connector types. While not intended to be a definitive guide, the following steps are given as a reference for the basic of optical fiber interconnection.

Cut the cable one inch longer than the required finished length.

Carefully strip the outer jacket of the fiber with “no nick” fiber strippers. Cut the exposed strength members, and remove the fiber coating. The fiber coating can be removed in two ways: a. by soaking the fiber for two minutes in paint thinner and wiping the fiber clean with a soft, lint-free cloth; b. by carefully stripping the fiber with afiber stripper. Be sure to use strippers made specifically for use strippers made specifically for use with fiber rather than metal wire strippers as damage can occur, weakening the fiber.

Thoroughly clean the bared fiber with isopropyl alcohol poured onto a soft, lint-free cloth such as kimwipes. NEVER clean the fiber with a dry tissue.

Note: Use only industrial grade 99% pure isopropyl alcohol. Commercially available medicinal and isopropyl alcohol is light mineral oil dilution water. Industrial grade isopropyl alcohol should be dedicated.

The connector may be connected by applying epoxy or by crimping. If using expoxy, fill the connector with enough epoxy to allow a small bead of epoxy to form at the tip of the connector. Insert the clean, stripped fiber into the connector. Cure the epoxy according to the instructions provided by the epoxy manufacturer.
Anchor the cable strength members to the connector body. This prevents direct stress on the fiber. Slide the back end of the connector into place (where applicable).

Prepare fiber face to achieve a good optical finish by cleaving and polishing the fiber end. Before the connection is made, the end of each fiber must have a smooth finish that is free of defects such as hackles, lips, and fractures. These defects, as well as other impurities and dirt change geometry transmission patterns of light and scattered.

Cleaving

Cleaving involves cutting the fiber end flush with the end of the ferrule. Cleaving, also called the scrible-and-break method of fiber end face preparation, takes some skill to achieve optimum results. Properly handled, the cleave produces a perpendicular, mirror-like finish. Incorrect cracks will cause the lips and the comb as shown in Figure 2. While cleaving may be done by hand, a cleaver tool, available from such manufacturers as Fujikura and FiberStore, allows for a more consistent finish and reduces the overall skill required.

The steps listed below outline one procedure for producing good, consistent cleaves such as the one shown in Figure 3. 1. Place the blade of the cleaver tool at the tip of the ferrule. 2. Gently score the fiber across the cladding region in one direction. If the scoring is not done lightly, the fiber may break, making it necessary to reterminate the fiber. 3. Pull the excess, cleaved fiber up and away from the ferrule. 4. Carefully dress the nub of the fiber with a piece of 12-micron alumina-oxide paper. 5. Do the final polishing. (See Figure 3.)

Polishing

After clean cleave has been achieved, the fiber end face is attached to a polishing brush, and the fiber is ground and polished. The proper finish is achieved by rubbing the computerized fiber end against polishing paper in a figure-eight pattern approximately sixty times.

To increase the ease and repeatability of connector installation, some companies provide the connector kits. Some kits are specific to the type of connector to be installed while others supply the user with general tools and informationi for connecting different types of connectors. Some connectors require the use of an alignment sleeve, also called an interconnection sleeve. This sleeve serves to increase repeatability from connection to connection.

Care and Handling of Fiber Optic Connectors

A number of events can damage fiber optic connectors. Unprotected connector ends can experience damage by impact, airborne dust particles, or excess humidity or moisture. Increase the optical output power of modern lasers may damage a connector, an often overlooked factor in discussions about handling and caring for optical fibers and connectors. Most designers tend to think of the power levels in optical fibers as relatively insignificant. However, a few milliatts at 850nm will do permanent damage to a retina. Today, optical amplifiers can generate optical powers of 1 watt of more into a single-mode fiber. This becomes quite significant when one considers that the optical power is confined in the optical core only a few microns in diameter. Power densities in a single-mode fiber carrying an optical power of 1 Watt (+30 dBm) can reach 3 megawatts/cm2 or 30 gigawatts/m2! To put it in everyday terms, sunlight at the surface of the Earth has a power density of about 1,000 Watts/m2. Most organic materials will combust when exposed to radiant energies of 100 kilowatts/m2. Clearly, power densities of 30 gigawatts/m2 deserve attention.

Cleaning

Another important thing to remember in handling fiber optic connector is that the fiber end face and ferrule must be absolutely clean before it is inserted into a transmitter or receiver. Dust, lint, oil (from touching the fiber end face), or other foreign particles obscure the end face, compromising the integrity of the optical signal being sent over the fiber. From the optical signal’s point-of-view, dirty connections are like dirty windows. Less light gets through a dirty window than a clean one. It is hard to conceive of the size of a fiber optic connector core. Single-mode fibers have cores that are only 8-9 µm in diameter. As a point of reference, a typical human hair is 50-75 µm in diameter, approximately 6-9 times larger! Fiber optic connectors need to be cleaned every time they are mated and unmated; it is essential that fiber optics users develop the necessary discipline to always clean the connectors before they are mated. It is also important to cover a fiber optic connector when it is not in use.

Handling

Never touch the fiber end face of the connector.
Connectors not in use should be covered over the ferrule by a plastic dust cap. it is important to note that inside of the ferrule dust caps contain a sticky residue that is a by product of making the dust cap. This residue will remain on the ferrule end after the cap is removed.

The use of index-matching gel, a gelatinous substance that has a refractive index close to that of the optical fiber, is a point of contention between connector manufacturers. Glycerin, available in any drug store, is a low-cost, effective index-matching gel. Using glycerin will reduce connector loss and back reflection, often dramatically. However, the index-matching gel may collect dust or abrasives that can damage the fiber end faces. It may also leak out over time, causing backreflections to increase.

Connectors Are Termination Of Cables And Other Applications

Fiber optic connector is a mechanical device mounted on the end of a fiber optic cable, light source, receiver, or housing, the connector allows these devices to be mated to a similar device. Of the many different connector types, connectors for both glass fiber cable and plastic fiber optic cable are available. The terminal ends of all fiber cable strands shall be field connectorized. It is IST’s practice to terminate both ends of all fibers within a fiber cable with ST, epoxy and polish style connectors. Termination of older cables may be of several types including mechanical or fusion spliced pigtails.

There are a number of connector styles on the market including LC, FC, MT-RJ, ST and SC, belong them the SC Connector is the most popular connectors. Manufacturers and distributors are more likely to have equipment to accommodate SC and ST style connectors than any other connector style. That should be a consideration when making product selections.

SC Connectors

SC connectors are used with single-mode and multimode fiber-optic cables. They offer low cost, simplicity, and durability. SC connectors provide for accurate alignment via their ceramic ferrules. An SC connector is a push-on, pull-off connector with a locking tab. Typical matched SC connectors are rated for 1000 mating cycles and have an insertion loss of 0.25 dB. From a design perspective, it is recommended to use a loss margin of 0.5 dB or the vendor recommendation for SC connectors.

FC Connectors

These connectors are used for single-mode and multimode fiber-optic cables. FC connectors offer extremely precise positioning of the fiber-optic cable with respect to the transmitter’s optical source emitter and the receiver’s optical detector. FC connectors feature a position locatable notch and a threaded receptacle. FC connectors are constructed with a metal housing and are nickel-plated. They have ceramic ferrules and are rated for 500 mating cycles. The insertion loss for matched FC connectors is 0.25 dB. From a design perspective, it is recommended to use a loss margin of 0.5 dB or the vendor recommendation for FC connectors.

ST Connectors

The ST Connector is a keyed bayonet connector and is used for both multimode and single-mode fiber-optic cables. It can be inserted into and removed from a fiber-optic cable both quickly and easily. Method of location is also easy. ST connectors come in two versions: ST and ST-II. These are keyed and spring-loaded. They are push-in and twist types. ST connectors are constructed with a metal housing and are nickel-plated. They have ceramic ferrules and are rated for 500 mating cycles. The typical insertion loss for matched ST connectors is 0.25 dB. From a design perspective, it is recommended to use a loss margin of 0.5 dB or the vendor recommendation for ST connectors.

LC Connectors

LC connectors are used with single-mode and multimode fiber-optic cables. The LC connectors are constructed with a plastic housing and provide for accurate alignment via their ceramic ferrules. LC connectors have a locking tab. LC connectors are rated for 500 mating cycles. The typical insertion loss for matched LC connectors is 0.25 dB. From a design perspective, it is recommended to use a loss margin of 0.5 dB or the vendor recommendation for LC connectors.

MT-RJ Connectors

MT-RJ connectors are used with single-mode and multimode fiber-optic cables. The MT-RJ connectors are constructed with a plastic housing and provide for accurate alignment via their metal guide pins and plastic ferrules. MT-RJ connectors are rated for 1000 mating cycles. The typical insertion loss for matched MT-RJ connectors is 0.25 dB for SMF and 0.35 dB for MMF. From a design perspective, it is recommended to use a loss margin of 0.5 dB or the vendor recommendation for MT-RJ connectors.

MTP/MPO Connectors

MTP/MPO connectors are used with single-mode and multimode fiber-optic cables. The MTP/MPO is a connector manufactured specifically for a multifiber ribbon cable. The MTP/MPO single-mode connectors have an angled ferrule allowing for minimal back reflection, whereas the multimode connector ferrule is commonly flat. The ribbon cable is flat and appropriately named due to its flat ribbon-like structure, which houses fibers side by side in a jacket. The typical insertion loss for matched MTP/MPO connectors is 0.25 dB. From a design perspective, it is recommended to use a loss margin of 0.5 dB or the vendor recommendation for MTP/MPO connectors.

There are also other types of connectors, have a wide seleciton of fiber connectors at FiberStore.

SFP+ Direct Attach Copper Cable Compares With 10GBASE-T





Direct Attach Cables (DAC) are high performance integrated duplex data link for bi-directional communication. And a SFP+ Direct Attach cable, also known as Twinax cables, uses SFP+ MSA and copper "twinaxial" cable with SFP+ connectors on both sides, provides 10 Gigabit Ethernet connectivity between devices with SFP+ interfaces. SFP+ Direct Attach Copper Cable is expected to be the optimum solution for 10G Ethernet reaches up to 10 m.

How does SFP+ Direct Attach Copper Cable Compare With 10GBASE-T?

1.10GBASE-T commonly used for 10MB, 100MB and 1GB network connections, while SFP+ Direct Attach Cable only for 10Gigabit Ethernet Network. And 10GBASE-T also support much longer distances than SFP+ Direct Attach Copper Cable.

The concept of standard, structured cabling provides a long-term underlying foundation of transmission infrastructure that follows a base set of engineering rules. 10GBase-T retains and abides by this by operating over the installed base of twisted-pair copper cable already in place for lower-speed applications. 10GBase-T uses the same cabling-link-negotiating concepts as do 1GBase-T, 100Base-T and 10Base-T, providing a clear path of bandwidth upgradeability as needed, by leveraging the existing pair infrastructure. Within a rack, following link segment specifications, the same 10GBase-T copper twisted-pair cabling will enable use with earlier Ethernet generations – 10MB, 100MB and 1GB operation. To extend this further, this same copper twisted-pair cabling is utilized outside the equipment distribution area (EDA) zone, connecting with horizontal distribution area in the data center.

As a technology, 10GBase-T enables network managers to preserve their knowledge base of Ethernet transport while seamlessly upgrading bandwidth capacity from 1G to 10G rates. Additionally, network managers preserve their underlying investment in the maintenance of standard, structured cabling systems. But SFP+ Direct Attach Cable is supported only on 10G ports. Do not insert a DAC into a 1G port.

The IEEE 802.3an-2006 10GBase-T Ethernet Standard specifies operation over standard, structured twisted-pair copper cable up to 100 meters. In contrast, 10G SFP+ Direct Attach is limited to 10 meters, with a reach of five to seven meters more commonly available. SFP+ Direct Attach cables longer than five meters are exponentially higher cost compared to shorter cables.

2. 10GBase-T offers the ability to field-terminate, while SFP+ Direct Attach cables cannot be field-terminated.

As a standard, structured cabling system, twisted pair cables are a known technology to data center cable technicians. Twisted pair cabling offers the ability to field-terminate, as needed, clean lengths in less than a minute. 10GBase-T implementations enable just such a clean, structured cable infrastructure.

SFP+ Direct Attach cables, in contrast, cannot be field-terminated. SFP+ uses a passive twin-ax cable assembly and connects directly into a SFP+ housing; they are specially terminated at the vendor site and must be purchased at pre-determined lengths. This adds overhead to cable management inventory, while preventing a clean, efficient cable infrastructure design.

3.Power Dissipation of 10GBase-T is higher than SFP+ direct attach cable.

At a physical layer (PHY) device level, 10GBase-T power consumption, whether at full 100-meter reach or 30-meter short reach mode, will be higher than SFP+ Direct Attach, including the electronic-dispersion-compensation chip. A 10GBase-T PHY, at the device level, can consume anything from two to four Watts per port compared to two Watts per port for SFP+ Direct Attach.

SFP+ direct attach cables are widely used in varies condition for short distance 10G transmission, and 10GBASE-T works with Cat 6 and Cat7 cable that are commonly used for 1Gb network connections, which all have their own special applications. 

 

 

The Survival of The Fittest of The Fiber Optic Connector

Looking at the current market can be described as quite a mixed bag of fiber optic connectors. On the premise of FTTH is popular, many companies has seen a market outlook. Have been started scrambling to grab market share. The market is very confusing, profits plummeted. Many enterprises in a dilemma. While operators central purchasing so many manufacturers were mixed, happy is the amount up, the worry is that the prices down, the market will be more difficult to do. At the cost of many manufacturers to reduce prices to squeeze into the operator’s Central Purchasing.

How to choose a qualified fiber optic connector? Have to identify its selection, structure and production.

A. Selection can be broadly divided into: Plastic V groove, rubber V groove, the metal V groove (copper or aluminum), the V grooves of quartz glass, pore and ceramic.

1. Plastic V groove

Plastic V-groove is the most common manufacturers to adopt a selection, which is mainly because of the ease of processing, low cost. Subject to cost constraints, most manufacturers the production of plastic V-groove many are not using the new PEI fiber optic connector production materials, or even replaced by other inferior materials, in order to have gained a place the operators reserve price bid. Did not pay too much attention from the injection molding equipment, especially some small businesses and private small workshops, ordinary injection molding machine to produce. Short-term performance of the connector is not much of a problem, a long time under the influence of accident by environmental factors will be frequent.

Furthermore plastic V-groove on machining accuracy inadequate by the material, injection molding equipment and the use of environmental impact prone to deformation of the warped; wearing fiber by fiber nearly 90 ° cutting surface, easy blowing debris into the internal contacts, causing the inside of the connector pollution caused by successive failed.

2. Rubber V groove

This material is not worth mentioning, rarely appear on the market. Simply can not afford because of its environmental factors.

3. The metal V groove

The material used on the market mainly copper and aluminum. Both can not escape the fate of being oxidized, and the processing of varying accuracy, easy to produce dander damage fiber. Insufficient strength will deform. Especially aluminum V groove, after repeated open the internal compression deformation space becomes large, the gripping force becomes small, the impact on the fiber optic splice performance.

4. The V grooves of quartz glass

This material V-groove is the use of PLC Splitter technology, industry recognized and recommended for use on site assembly type fiber optic connector internal connecting way. The main advantage of its very high machining accuracy, can be controlled in 1μ between. Fiber breakpoint between successive favorable attenuation in the hot melt comparable. And to wear fiber smooth and difficult to produce debris. No deformation, resistance to environmental performance is extremely strong.

5. The Pores, Ceramic type

With respect to the error between the fiber diameter and the diameter of the pores, but it is a defect. Diameter optical fibers and optical fiber itself thers is error, combined with the pore itself there is error. Accumulated error is at least a 3-micron industry report 1μ, contact the loss of fiber contacts between the dislocation will be more than 0.2 dB. Nor due to contact between the fixed, the earthquake became its fatal flaw.

Field fiber optic connector is not PLC splitter. Optical Splitter by the factory processing, the handing of its internal contacts are in the operating microscope to ensure that its internal pollution. And assembled on site fiber optic patch cords, need to respond to the very harsh environment of the construction site. In this context, bear the brunt of the factory production environment.

You may understand the PM2.5 particles of dust in the air everywhere. Superior production environment is a necessary prerequisite for the production of connectors, on this basis, also need refinement of each production. So as to ensure the production of fiber optic connectors have been qualified. This is why some manufacturers out connector at room temperature, a passing rate of about 90%, and some manufacturers can do more than 99% of the one-time pass rate.

I believe that do the points above, but the factors used in the actual environmental conditions is very important. Do not just look at the room temperature performance, not just blindly concerned about the price. A qualified and superior fiber optic connectors must be able to withstand a long time in the harsh environment performance online, do not be confused by the immediate moment.

It is worth mentioning here have been some manufacturers have begun to study the next generation of fiber optic connected to the cold continued transmission mode, so that the optical and the optical transmission between points. Such technology would ban docking between the fiber break dependence on fiber matching cream. And does not require professional support construction tools, can achieve real store of, so that users can do-it-yourself operation, like changing a light bulb so simple and quick.

The Core Components of The Fiber Optic Connector: Ceramic Ferrule

What is ceramic ferrule? As the name suggests, the main material of the ceramic ferrule is ceramics, however, thia is not just ceramic so simple. Ceramic ferrules must be used in fiber optic communication, it is to ensure the communication quality is a very important role.

We all know that fiber connection technology is divided into two categories, one class is permanently connected, often called fixed joints dead joints; another class activities removable connection, often referred to as the union, need to use fiber optic connector. In the transmission network, a fiber optic cable connection between the permanent connection, the optical fiber connector is mainly used to implement the system between devices, between the equipment and instruments, equipment and between the optical fibers and the optical fibers and optical fiber between nonpermanent the fixed connection, it is the optical communication system of the most widespread and the largest use of basic passive devices. Matching ceramic material with quartz fiber thermal, physical and chemical properties and stability, as the core device with ceramic ferrule fiber optic connectors has been developed rapidly.

The most important role of the ceramic ferrule fiber physical docking (also known as fiber cold splice), often used in conjunction with ceramic sleeve, Ceramic cylindrical tube fired zirconia ceramic ferrule, hard texture, delicate white color accuracy of the finished sub-micron level, is the most commonly used in optical fiber communication network, the largest number of precision positioning pieces, often used for the manufacture of the optical connector, the optical coupling of the devices, and the like.

Like the ciruit in the plug and receptacle, the ferrule and sleeve are the key components of fiber optic connector. The diameter of only 0.125mm optical fiber must pass through the inner bore of the ceramic ferrule, and to maintain a linear transmissin of the state; connected to the outgoing optical fiber in the other end of the ceramic ferrule. Straight and precise connection directly affect the transmission efficiency of the optical fiber. Ceramic ferrule is not only highly internal hole diameter, while the outer diameter and concentricity requirements higher. And the optical connector because of the need for multiple plug, after repeated use must maintain the same accuracy of the same, very high demands on the material density.

The ceramic ferrule classification and features

Ceramic ferrule in accordance Dimensions is divided into three categories of SC, LC, and non-standard, in accordance with its precision, can be divided into two kinds of single-mode and multimode. The industry is often referred to as SC singlemode ferrule SC multimode ferrule LC singlemode ferrule LC multimode ferrule non-standard ferrule.

The ceramic ferrule characteristics depend on the characteristics of the material zirconia, mainly reflected in the good thermal stability, high hardness, high melting point, and wear-resistant, high machining accuracy.

Source: www.fs.com

Application of Fiber Optic Connector and Its Terminal Consider Analysis

BNC connectors commonly used with the A/V industry, fiber connector with fiber optic technology continues to mature gradually. Copper connectors on the AV system signal loss generally will not be great, the optical connection is different, its transmission system interface will play a very large effect. Let’s take a look at some of the issues arising in fiber physical connection, fiber optic transmission equipment itself may direct connection, but in some cases, most or almost all of the fiber optic transmission connectivity options are artificially personally. The amount of signal loss by the quality and type of the used optical fiber cable, each connecting end will produce a certain signal is lost. According to the user to select different types of fiber connector, connecting end signal loss add up to the total amount may exceed the amount of fiber optic cable signal loss.

To maintain the normal operation of the system

In the fiber optic system design, the system is capable of normal operation, we achieved very good results, we need to consider some unexpected problems may appear in the system design, and want the system to achieve the effect of normal operation. System design, we have to take into account the worst case may appear and make appropriate plans, looking forward to better operational results. Fiber optic connector design certainly want this idea to heart. In system design, security, stability and system connection requirements the end of the fiber is smooth, Founder. The connection between the client and the client must be precise, micron accuracy or millionths of a meter. Commonly used in the multimode fiber from 50-62.5 microns in diameter, while the diameter of the single-mode fiber is only 8-9 microns. This diameter size of a human hair (17-180 microns) in diameter compared to see any trace of error can bring catastrophic losses.

The fiber optic connection very stringent precision requirements, the connector must be very clean. Fiber optic connectors and accessories are usually mounted on a set of house, a finger print or external dust may seriously affect the performance of the connector, and even lead to transmission failure. Therefore, the connector is not connected, it should be stored in clean protective sleeve in.

In connection, we should also fiber optic connector wedge tight “ferrule” all optical fiber connector design to ensure accurate when the connector with. The optical fiber terminal is inside the ferrule, become a permanent element by adhesive or crimping tight hoop. A built-in optical fiber is inserted, put the ferrule end ground smooth, smooth interface connector fiber optic connection. Ferrules are usually made from a relatively hard material such as ceramic, of course, can also be stainless steel, plastic, or made of a tungsten carbide material, the SC, ST and FC universal ferrule diameter of 2.5mm, the LC common ferrule diameter 1.25mm. Can be due to the functional characteristics of the ferrule to be produced in accordance with the precision requirements, fiber optic connector will become the primary determining characteristics. In connection ferrule, the spring container ferrule guarantee coaxial alignment between the optical fiber and LED or laser source.

With the expansion of technology development and application of fiber optic connectors rapid development. Now in the market the use of optical fiber connector is about 12 or more, each of which is to meet a specific need arises at the historic moment, of course, there are certain technical limitations. Market trend toward a moderate price, compact connector mode development, greater transmission density to support the requirements of the new transmission distribution system. As users expect that the continuous development of the telecommunications industry also contributed to the large scale application of the optical fiber, in large part due to rapid growth in the demand due to the types of communications and entertainment services on the fiber optic connection.

Terminal Consider

Traditionally, fiber optic terminal is generally slower, higher prices are also high, the equipment and technical requirements. Consider fiber singlemode cable terminal, you should take into account several factors. In some cases, we can choose according to various fiber types set up the terminal cable.

The tailor-mount applications, we can only select a specific terminal, but spliced tools, can reduce the length of single-mode fiber-site terminal extension, reduce the number of demand and technology use. For multimode optical fiber cable, spliced new method uses a simple optical fiber cutting method, the cable to be assembled into a pre-designed connector / cable. This method is very simple, just a fiber-to-fiber connector butt joints are usually used a special optical gel fiber terminal condensation.
Source: FiberStore.com