A fiber optic coupler is a device used in fiber optic systems with single or more input fibers and single or several output fibers, which is different from WDM  devices. WDM multiplexer and demultiplexer divide the different wavelength fiber light into different channels, while fiber optic couplers divide the light power and send it to different channel.

Bandwidth
Most types of couplers work only in a limited range of wavelength (a limited bandwidth), since the coupling strength is wavelength-dependent (and often also polarization-dependent). This is a typical property of those couplers where the coupling occurs over a certain length. Typical bandwidths of fused couplers are a few tens of nanometers. In high-power fiber lasers and amplifiers, multimode fiber couplers are often used for combining the radiation of several laser diodes and sending them into inner cladding of the active fiber.

Structure
A basic fiber optic coupler has N input ports and M output ports. N and M typically range from 1 to 64. M is the number of input ports (one or more). N is the number of output ports and is always equal to or greater than M. The number of input ports and output ports vary depending on the intended application for the coupler.

Light from an input fiber can appear at one or more outputs, with the power distribution potentially depending on the wavelength and polarization. Such couplers can be fabricated in different ways:
Some couplers use side-polished fibers, providing access to the fiber core;
Couplers can also be made from bulk optics, for example in the form of microlenses and beam splitters, which can be coupled to fibers (“fiber pig-tailed”).

Types
Fiber optic couplers can either be passive or active devices. Passive fiber optic couplers are simple fiber optic components that are used to redirect light waves. Passive couplers either use micro-lenses, graded-refractive-index (GRIN) rods and beam splitters, optical mixers, or splice and fuse the core of the optical fibers together. Active fiber optic couplers require an external power source. They receive input signals, and then use a combination of fiber optic detectors, optical-to-electrical converters, and light sources to transmit fiber optic signals.

Types of fiber optic couplers include optical splitters, optical combiners, X couplers, star couplers, and tree couplers. The device allows the transmission of light waves through multiple paths.

Fused couplers are used to split optical signals between two fibers, or to combine optical signals from two fibers into one fiber. They are constructed by fusing and tapering two fibers together. This method provides a simple, rugged, and compact method of splitting and combining optical signals. Typical excess losses are as low as 0.2dB, while splitting ratios are accurate to within ±5 percent at the design wavelength. The devices are bi-directional, and offer low backreflection. The technique is best suited to singlemode and multimode couplers.

Choices for fiber optic coupler also include Single window narrow band, Single window Wide band, and Dual window Wide band fiber optic coupler. Single window fiber optic coupler is with one working wavelength. Dual window fiber optic coupler is with two working wavelength. For Single mode fiber, is optimized for 1310 nm and 1550 nm; For Multimode fiber, is optimized for 850 nm and 1310 nm.

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.

At the time that Cisco involved in the “Prism” incident, the market research firm Synergy Research Group released data show that Cisco has beat IBM and HP and become the largest provider of IT products. While Cisco’s annual revenue in China has exceed 1.6Billion USD, accounting for 30% of the total profits.

Last week, former CIA employee Edward Snowden's "prism leak door" is called reality version of American movies, handsome agent, glamorous pole dancing girlfriend, sophisticated state secrets, betrayal and exile, the Secret bureaucratic system and lies, cohabitation Kong, depressed black president, personal privacy and national conflicts of interest ...... various elements are available, and some even have played a good title: "leaker Snowdon."

This is the so called “Prism”, This is called "Prism", the secret use of a super software to monitor Internet users and telephone records. Now, about a hero or a traitor Snowdon debate is still in progress, Snowden's whereabouts is still pending. Apart from these troubles to see companies and industries involved, the stakes is obvious.

According to Snowden’s disclosing, Google, Yahoo, Microsoft, Apple, FaceBook, AOL, PalTalk, Skype, YouTube and other nine companies has been involved in espionage allegations, these companies are suspected to have open the servers to the U.S National Security Agency, allowing the government to easily monitor millions mails, instant calls and access of the data of millions of Internet users worldwide.

Subsequently, these companies strongly denied the charges. But by June 14, Facebook, Microsoft for the first time admitted that the U.S government did have asked for user data from them and they have published some of the information and data content in order to get rid of the morass “Prism door” as soon as possible.

At the same time, China domestic media has shifted the perspective of some U.S communication companies which may threat the national potential information security, such as Cisco because Snowdon exposed the NSA monitor Chinese network and computers via Cisco routers.

Allegedly, Cisco have participated almost all the large network projects, involving government, customs, postal services, banking, railways, civil civil aviation, medical, military and other critical sectors of network construction, as well as China Telecom, China Unicom and other telecom operators network infrastructure. China Telecom 163 and China Unicom 169 is the two of Chinese most important backbone networks, both of which has carries more than 80 percent of China's Internet traffic. But in these two backbone network, Cisco accounted for more than 70% share, and dominated all the super-core nodes.

However, Cisco is the main supplier of equipment and network technology of American government and military communications. In 2006, the In 2006 the United States 115 government departments involved a "Cyber ​​Storm" network warfare exercises, Cisco is one of the designers of the important exercises. Therefore, security experts worry that once the war broke out, the U.S. government is likely to take advantage of Cisco products deployed worldwide to launch cyber warfare, the implement a fatal strike of their enemy.

Some fine moves of Chinese telecommunication operators may reflect this concern, In October last year, China Unicom completed 169 core backbone network node cluster router Wuxi relocation project, which is the communications industry's first cluster of Cisco routers relocation project. This is likely to be a landmark event, indicating that China's telecommunications companies have begun to address the issue of information security, and began to carry out the replacement of existing network equipment.

At the time that Cisco involved in the “Prism” incident, the market research firm Synergy Research Group released data shows, Cisco has beat IBM and HP and become the largest provider of IT products. While Cisco’s annual revenue in China has exceed 1.6Billion USD, accounting for 30% of the total profits. It can be expected, “prism” incident may make Cisco’s business in China clobbered. In addition to Cisco, it is anticipated Microsoft, Apple and other companies’ business in Chinese will also be affected.

In fact, at the time of the U.S blocked Huawei, ZTE last year, security experts had called on on the government should pay attention to our country’s network security issues. Therefore, I believe, in the rise of cloud computing and big data, the state the state has been increasing emphasis on network and information security at the time, "prism" incident is a bigger warning, perhaps the next will be on our network security legislation, the government , the central enterprises, the military and other domestic purchases made ​​explicit.

From the enterprise technical reserves point of view, China's current level of communication technology has reached world standards, local businesses have been able to build a comprehensive bearer network and security operations. Therefore, the upgrade national information security strategy will not only be good for Huawei, ZTE and other communications equipment manufacturers, but also benefit the extensive companies involved in cloud computing, big data.

For example, the forthcoming cloud computing standards will likely pay more attention to security issues, which will enable local production of hardware and software, system integration and cloud computing platform provider usher in greater development space. Similarly, large with respect to data center construction and maintenance, data processing, speech recognition, IT consulting, information security and other enterprises will usher in a huge business opportunity.

Published by FiberStore, industrial news - www.fiberstore.com

For cabling, telecommunication rooms and equipment rooms are the convergence of three businesses including data, voice and image, and its importance is self-evident. So making great efforts in their overall design, equipment stereotypes, hardware configuration, maintenance and other aspects of construction. However, the construction side always tends to ignore the largest number of equipment maintenance and installation of security - fiber optic cables and fiber patch cables in the telecommunications rooms and equipment rooms. While ignoring the problem will bring us a lot of trouble to the machine room management therefore I believe that it is necessary to have proper fiber optic patch cord management operations.

In general, reasonable patch cables management can be divided into five processes: planning, preparation, wiring, testing and verification.

1. Planning

For patch cables management, should be prepared the requirements planning including present and future.

1.1 Change Requests. A variety of management activities, move, add or change (MAC) all began in the change requests. Change requests must contain all the necessary information about starting the planning procedures.

1.2 Search Records. After receiving the request table, searching the coping recording, in order to determine the circuit paths used.

1.3 Correct Routing. Before determine the correct length of fiber optic patch cord, we should first find out the best route between the ports. Usually the shortest route is passing from the horizontal and vertical cable. Moreover shall not obstruct or interfere with the other jumpers or connectors in the distribution frame. When select fiber optic patch cables, should avoid excessive laxity, ensure the appearance clean and tidy. Jumper too tight will increase the pulling force of connectors, whereas overwork slack will bring trouble to jumper management, increase the patch panel's management difficulty.

2. Preparation

Before the implementation of management, you should do prepare as much as possible, to research the management records. Determine the label information of connection and reconnect port location and the relevant ports.

2.1 First check the require patch cable model, and then check the quality of the jumper. To ensure the quality of the jumper is correct, need to check whether the jumper is damaged. In order to check it is damaged or not, of course you can from the appearance of the jumper, if possible, use professional equipment to check.
2.2  Then check the situation of the require connecting portion, in order to avoid physical damage to the connection parts.
2.3  Finally need to clean the jumper joints and the connecting parts.

There are two ways available to clean the fiber connectors: contact and non-contact.

Contact Cleaning Method:
(1). Wiping paper and anhydrous alcohol, using raw wood pulp with special processing technology, ultra-low dust, pure texture, high performance water absorption, delicate, will not scratch the surface swabbed, with a low dust wipe with no water-alcohol wipe on fiber optic connectors;
(2). Non-woven fabric, does not produce lint, tough, without any chemical impurities, silky soft, does not cause allergic reactions, and not easy to fluff and hair loss, as the ideal choice for cleaning fiber optic connectors or pins on the production or testing, wipe fiber optical connector with no water-alcohol;
(3). Cleaning cotton swabs, specifically designed for ceramic casing internal cleaning or for cleaning the ferrule end face of the flange (or adapter) which is not easy reached;
(4). Professional cleaner, fiber optic connector special cleaner uses special cleaning wiping belt, mounted in a scramble enclosure, no alcohol, each cleaning is very effective and produces a new surface, convenient and practical.

Non-Contact Cleaning Method:

(1). Ultrasonic cleaning method, it replaces clean liquid into ultrasonic "column" to the connector end surface, and waste recycling and sucked clean in the same small space;
(2). High-pressure blowing method, its principle is at the connector end first coated with cleaning fluid, and then use high-pressure gas blowing at the connector end surface;

2.4 Check the fiber optic connector cleanliness

After finish cleaning fiber optic connectors, must check the terminated surface. General practice is to use a magnifying glass 100, 200 times or 400 times to check, the figure below shows the fiber end-face in a pure state and a contaminated state.

Patch cable management person, no matter using which method mentioned above, for some serious pollution or difficult to clean connectors, needs to use cotton swabs, alcohol and other cleaning fluid to handle.

After this series of preparatory work, it means the wiring work of patch cable management is to expand.

3. Wiring

Patch panel installation, should base on operational procedures to complete various stages of any work. Patch cable construction kinks, glitches, bad pinch and bad contact are likely to significantly reduce the jumper performance. To avoid such problems, you should focus on the following factors:

(1). Bending radius
The minimum bending radius jumper allows need to comply with the jumper manufacturer operating specifications.

Standard says, the minimum bend radius of unshielded twisted pair (UTP) cable should be at four times as the diameter of fiber optic cable, shielded twisted-pair cable is as eight times as the diameter of fiber optic cable. The minimum bend radius of 2-core or 4-core horizontal cable is greater than 25mm, if the bending radius is smaller than this standard, it may lead to a change in the relative position of the wire, resulting in reduced transmission performance.

(2). Jumper tensile and stress
During wiring process, not excessive force, otherwise it may increase the stress on jumpers and connectors, resulting in decreased performance.

(3). Bundle
The jumper is not always needed bundling, if bundled strapping manufacturers need to comply with the principle, not tied too tight, otherwise it will cause a twisted pair variant. Do not over-tighten the clamp, the jumper should be able to freely rotate. Please use a dedicated product, consider choosing repeated use products without tools, such as nylon sticking with buckle belt.

4. Testing

Even after the jumper wiring completed, but may be that if the fiber links or copper links are in full compliance with operating specifications or cabling international and national standards. Then it should be fiber or copper testing, only in accordance with the testing standards, then can determine whether it passes the test standard.

5. Verification

(1). It is worth spending the time to the final visual inspection of the connection. Ensure that the jumper relaxation not knot, is not a cabinet door clamp.

(2). The final step is based on the existing configuration update records, close and have completed the change request related work orders.

Now the fiber optic cable is one of the most important components of integrated wiring system, especially good management operation of fiber jumpers in the data center project, is particularly prominent. Believe that as construction management personnel reasonably jumper management operates, will make the entire comprehensive wiring system become advanced, scientific, practical and reliable.

With the large number applications of 10G/40G/100G network in data center, on-site installation and management of fiber optic patch cable becomes increasingly important, the jumpers management sometimes affect the overall channel attenuation, good management ensures fiber channel data transmission in the most excellent condition, process-oriented operations such as planning, preparation, wiring, testing and verification have important significance to assurance the quality of the system.

Networking solutions advance at an unbelievably quick charge with new and faster kinds of cables hitting theaters often. If you possess the community that utilizes the standard form of Ethernet wires and the other community which utilizes the greater quickly and far more reputable dietary fiber optic wires, it will be possible and better to connect all of them collectively having a special number of Fiber to Ethernet Converter.

To permit several networks which are utilizing various types of cabling to talk with each other, a brand new fiber optic Ethernet Media Converter attaches an Ethernet cable at one end into an optic wire on the fresh finish. Furthermore, it could be utilized inside exact same community if multiple computers are earning utilization of distinct technologies or otherwise all of them have the capability to utilize fibers optic wires.

Fiber optic cables are extremely resistant to interference through electronics, wireless systems, or mobile phones, in contrast to the much more unpredictable standard Ethernet wires which could usually lose their signal in the event that exposed to specific kinds of products. This is the primary reason this is a smart decision to transform Ethernet wires to fibers optic wires, as it supplies a quicker signal than Ethernet is capable of doing delivering or receiving.

Some fiber converters will function using any sort of Ethernet cable tv whilst others have only ports of either the exact 100 megabit or the 10 Gigabit speed Ethernet wires, such as the 10 Gigabit Ethernet converters. The maximum speed at which information is ready to become transferred at around the quicker type of cable tv may slightly be lowered whenever a converter is connected among two numerous types of converter cables. Varied brands and kinds of converters like Cisco in addition to HP will have diverse velocity caps.

Ethernet Media Converters are obtainable in assorted sizes. Some are especially designed for the size of your home or office network. Nearly all converters are made of small plastic units that are meant to change a single Ethernet cable tv to an exclusive dietary fiber optic cable television. Greater converters can be found. They’ve the capability to be able to convert a large number of cabling at once and therefore are attached directly onto the metal rack. Just be sure they are positioned within a guaranteed community room

Fiber Media Converters should be included in a secure location so they cannot be disturbed through folks or machinery. In case of the converter is removed or perhaps broken, each pc coupled to the fiber optic cable might lose its Internet connection. Special care must be given to these community options. In addition, you need to maintain converters in managed temperature rooms that by no means get to less well as to cold because of the fact they include unique materials that merely get the job done correctly in a few conditions.

Fiber optic cables that continue to function after being converted coming from an Ethernet cable tv have a range that’s assessed in miles. Thus, huge companies with massive networks or net service suppliers make the most of Ethernet Media converters. And, soluble fiber optics can greatly extend serialized communication reach, and also the necessary adapters and converters are usually inexpensive, dependable, and readily available.

While Fiber Media Converters are employed in the Ethernet-based system, serial data communication is not limited to distance anymore. Ethernet Media Converters can effortlessly deal with 10BaseT/100BaseT/1000BaseT rates and gigabit-ready converters are obtainable too. Take benefit of this innovative networking technology right now.