Know the type of fiber, fiber cable, jumper, pigtail, and connector

To understand the types of optical fibers, optical cables, jumpers, connectors, and adapters, you first need to know the relationship between these products.

 

Optical fiber

The optical fiber is drawn from silica glass through a complicated process, it is a highly transparent glass filament, which is also called optical fiber.

Optical fiber type

Optical fiber is divided into single mode fiber and multimode fiber according to the transmission mode. Light enters the optical fiber at a specific angle of incidence, and full emission occurs between the optical fiber and the cladding. When the diameter is small, only one direction of light is allowed to pass through, which is a single-mode optical fiber; when the diameter of the optical fiber is large, light can be allowed to inject and propagate at multiple angles of incidence, that is a multimode fiber.

Single mode optical fiber

Normally, there are two types of optical fiber: single mode and multi mode. Single-mode fiber is a single glass fiber strand used to transmit a single mode or ray of light. Single mode fiber with a relatively narrow diameter, through which all signals travel straight down the middle without bouncing off the edges. Single-mode fiber features only one transmission mode. Single Mode Fiber with a relatively narrow diameter of 8.5 to 9.5μm, through which only one mode will propagate typically 1310 or 1550nm. 

Multimode optical fiber

Multi mode fiber is an optical fiber that allows multiple guided modes to be transmitted. Multi-mode fiber has a larger diameter core, typically 50 or 62.5μm. This larger core allows multiple modes of light to propagate. The standard wavelengths of the multimode are 850 nm and 1300 nm. Multimode fiber is available in four classifications: OM1 (62.5/125 µm), OM2, OM3, OM4 (50/125 µm). There’s also a new multimode fiber standard known as WBMMF (wideband multimode fiber) which uses the wavelengths between 850nm and 953nm.

Both single mode fiber and multimode fiber have a cladding diameter of 125μm.

G652，G657 fiber

According to the ITU standard, there are seven kinds of fibers: G651, G652, G653, G654, G655, G656, G657, and G652 and G657 are commonly used.

G652 fiber is the most widely used fiber in the metropolitan area network. It is a standard single-mode fiber with a zero-point dispersion of 1300nm. G652 fiber is subdivided into four types: G652A, G652B, G652C and G652D. The main difference lies in PMD. Among them, G652D is more commonly used. Because of its low fiber dispersion at 1300nm operating wavelength, the transmission distance of the system is only limited by loss.

G657 is a bending loss-insensitive fiber, and it is the most commonly used fiber optic cable for FTTH because of its better performance. But G657 fiber is more expensive than G652D.

G651 is a multi-mode optical fiber, mainly used in multi-tenant, residential buildings, and enterprise networks in FTTH networks. Its bending radius is half that of G652 fiber. It is suitable for indoor and FTTH cabling.

OS1, OS2, OM1, OM2, OM3, OM4, OM5

OS1 and OS2 are both single-mode optical fibers. OS1: the ordinary single-mode optical fiber used earlier; OS2: the ordinary optical fiber in use now, the low-water peak optical fiber. In general, OM1 is conventional 62.5/125μm; OM2 is conventional 50/125μm; OM3 is 850nm laser-optimized 50μm core multimode fiber, and in 10Gb/s Ethernet with 850nm VCSEL, the fiber transmission distance can reach 300m; OM4 is an upgraded version of OM3. OM4 multimode fiber optimizes the differential mode delay (DMD) generated by OM3 multimode fiber during high-speed transmission. Therefore, the transmission distance is greatly improved, and the fiber transmission distance can reach 550m; OM5 is a new standard for fiber patch cords defined by TIA and IEC with a fiber diameter of 50/125μm. Compared to OM3 and OM4 fiber patch cords, OM5 fiber patch cords can be used for higher bandwidth applications. The bandwidth and maximum distance are different for different levels of transmission.

 

Optical cable

The optical fiber is drawn from pure quartz with a special process into a glass tube thinner than a hair with a few mediums in the middle. Its texture is brittle and fragile, so an additional protective layer is needed. The outer layer of the optical fiber is combined with a plastic protective tube and a plastic sheath to form an optical cable.

Optical cables include fibers. Broadly speaking, optical fibers are optical cables, which are all transmission media. But they are also difference. The difference between optical fiber and optical cable: optical fiber is a thin and soft medium that transmits light beams. Most optical fibers must be covered by several layers of protective structures before use, and the covered cables including fibers are called optical cables. Therefore, the optical fiber is the core part of the optical cable, and the optical fiber forms the optical cable through the protection of some components and the auxiliary protective layer.

The type of fiber optic cable

There are many classification methods to categorize fiber optic cables, such as:

Classified by material: LSZH, PVC, HYTREL 7246, HYTREL 7237, PE, TPU

According to the outer diameter: φ0.9, φ2.0, φ3.0……

Divided by mode field: single mode (9/125), multimode (50/125, 62.5/125)

Divided by color: single mode is yellow, multimode is orange (OM1/OM2), OM3 is aqua blue, OM4 is aqua blue or violet, OM5 is lime green.

According to the structure, it can be divided into: generally simplex or duplex, duplex in single-tube, mini multicore, branch cable

Optical fiber brands: Corning, YOFC, Fujikura, Sumitomo, OFS, etc.

 

Type of patch cord

The 0.9, 2.0, and 3.0 of the optical fiber jumper are used to distinguish the outer diameter of the optical cable. 0.9 means the outer diameter of the optical cable is 0.9mm, 2.0 means the outer diameter of the optical cable is 2mm, and 3.0 means the outer diameter of the optical cable is 3mm.

There are also single-mode fiber jumpers and multi-mode fiber jumpers. Single mode is indicated by yellow, and the transmission distance is longer; multimode is indicated by orange, and the transmission distance is shorter.

 

Pigtail

Only one end of the pigtail has a connector, and the other end is a broken end of an optical cable core, which is connected to other optical cable cores through fusion splicing. It often appears in the optical fiber terminal box and is used to connect the optical cable to the optical transceiver.

Type of connector

Divided by the connection mode: FC, SC, ST, MU, LC, MT, E2000, MTRJ

Divided by fiber end face: PC, UPC, APC, SPC

According to the number of cores of the optical cable, it can be divided into: single core, double core (with clip)

Commonly used connectors: FC/PC, SC/PC, SC/APC, LC/PC

According to the tail sleeve structure, it can be divided into: round tail sleeve, square tail sleeve, conventional tail sleeve, short tail sleeve

 

Why should the fiber end face be divided into PC,UPC,APC

There are many reasons to caused fiber loss caused during fiber connections, such as: different axis (single-mode fiber coaxiality is required to be less than 0.8μm), the end face is not perpendicular to the axis, the end face is not flat, the butt core diameter is not matched, and the splicing quality is poor.

In order to make the end faces of the two optical fibers better contact, the end faces of the ferrule of the fiber jumper are usually ground into different structures. Common grinding methods are mainly: PC, APC, UPC. PC/APC/UPC represents the front surface structure of the ceramic ferrule.

 

Different fiber end face finishes

PC (Physical Contact).The two end faces are polished to be slightly curved or microspherical, and the fiber core is at the highest point of the bending. This eliminates the air gap and forces the fibers into physical contact.

UPC (Ultra Physical Contact) is based on the PC to optimize the end face polishing and surface finish, the end face looks more dome-shaped. The end face of the UPC connector is not entirely flat, and there is a slight arc to achieve more accurate connecting.

APC (Angled Physical Contact). The end face of APC is usually polishing into an 8-degree angle. The 8° angled bevel makes the fiber end face tighter and reflects light through its beveled angle to the cladding instead of returning directly to the source, providing better connection performance. 

The APC fiber optic connector is usually green. UPC/PC connectors are easily identified by their blue color on the connector boot.

Type of adapter

Optical fiber adapters are used to convert various optical fiber equipment and optical fiber connection methods. With the wide application of fiber optic adapters in fiber optic connections, there are various fiber optic adapters with different interfaces to choose from to adapt to different environmental installation requirements. Common types of adapters are: LC adapter, FC adapter, SC adapter, ST adapter, E2000 adapter, MTP / MPO adapter, etc.

 

HYC is a leading passive optical component OEM/ODM manufacturer, focusing on providing customers with efficient manufacturing, high-quality products and in-depth research and development. The main products are: fiber optic connectors (high-density optical connectors for data centers), WDM wavelength division multiplexers, PLC optical splitters, MEMS optical switches and other four core optical passive basic devices, which are widely used in fiber to the home , 4G/5G mobile communications, Internet data centers, national defense communications and other fields.

A comprehensive understanding of fiber optic connectors

Optical fiber connectors are used most often to transmit light by connecting two optical fibers instead of splicing. It is a flexible device that widely used in fiber-optic communications systems. Optical fiber connectors ensure precisely connections between the two ends of the fibers so that the optical energy output from the transmitting fiber can be coupled to the receiving fiber to the maximum extent. Better connectors will have little impact on the system due to its involvement. Since the outer diameter of the optical fiber is the only 125um, and the light passing core is smaller. The cores of single-mode fiber are only 9um, and the multi-mode optical fiber has 50um and 62.5um. So it is important to ensure the properly aligned.

Main component: Ferrule
One of the most important main components of fiber optic connector is ferrule. The quality of the ferrule directly affects the precision connections of the two fibers. Ferrule is usually made of different materials such as ceramic, metal or plastic. Most of the ferrules used in optical connectors are made of ceramic material (zirconia) due to its hardened characteristics, such as good thermal stability, high hardness, high melting point, wear-resistance, and high processing precision. The inner diameter of the ceramic sleeve is slightly smaller than the outer diameter of the ferrule, and the slitted sleeve tightens the two ferrules for precise alignment.

In order to make the end faces of the two fibers better contact, the ends of the ferrules are usually poshing into different structures. PC, UPC, and APC are the polish styles of ferrules inside the fiber optic connectors. PC is Physical Contact. The two end faces are polished to be slightly curved or microspherical, and the fiber core is at the highest point of the bending. This eliminates the air gap and forces the fibers into physical contact. APC is Angled Physical Contact. The end face of APC is usually ground into an 8-degree angle. The 8° angled bevel makes the fiber end face tighter and reflects light through its beveled angle to the cladding instead of returning directly to the source, providing better connection performance. UPC (Ultra Physical Contact) is based on the PC to optimize the end face polishing and surface finish, the end face looks more dome-shaped. Connector connections need to be in the same end face structure, for example, APC and UPC cannot be combined, resulting in poor connector performance.

Basic parameters: insertion loss, return loss
Due to the different ferrule end faces, the performance of the connector loss is also different. The optical performance of fiber optic connectors is primarily measured by two basic parameters: insertion loss and return loss. So what is the insertion loss? Insertion Loss (“IL”) is the loss of optical power caused by the connection. It is mainly used to measure the optical loss between two fixed points in optical fiber, which is usually caused by the transverse deviation between two optical fibers, the longitudinal gap in optical fiber joints, the end mass, etc. The unit is expressed in decibels (dB). Lower the insertion loss, better the performance. The general requirement should be no more than 0.5dB.

Return Loss (“RL”) refers to the parameter of signal reflection performance. It describes the power loss of optical signal return/reflection. The value is usually expressed in decibels (dB). The larger, the better. The typical RL value of APC connector is about -60db, and that of PC connector is about -30db.

Except for the two optical performance parameters of insertion loss and return loss, there are also other parameters should be considered including the interchangeability, repeatability, tensile strength and operating temperature of the fiber optic connector.

Fiber optic connector types
There are various fiber connector types in the market, such as LC, SC, FC, ST, MU, MT, MPO/MTP and so on.

LC connector
The LC optical connector is made with an easy-to-use modular jack (RJ) latch mechanism. The size of the pins and sleeves used in the LC connector is 1.25 mm, which is the half-size of SC, FC, etc..

SC connector
SC fiber optic connector (‘Subscriber Connector’ or ‘Standard Connector’) is a snap-on standard square connector, which features a push-pull coupling mechanism, and does not need to be rotated. This type of connector is usually made of engineering plastics, which are inexpensive and easy to insert and remove.

FC connector
FC fiber connector (Ferrule Connector) and the SC connector are the same sizes, except that the FC is made of a metal sleeve and the fastening method is a turnbuckle. It has the advantages of simple structure, convenient operation, easy manufacture, and durability, and can be used in a high vibration environment.

ST connector
The ST fiber optic connector (Straight Tip) has a rounded outer that made by a 2.5mm ring-shaped plastic or metal. The bayonet-style keyed coupling mechanism, which is commonly used in fiber distribution frames.

MTP/MPO connector
The MTP/MPO fiber optic connector is a special type of multi-fiber connector. The structure of the MPO connector is complex, connecting 12 or 24 fibers in a rectangular fiber ferrule.

In addition to the above, the connector types include MU connectors, MT connectors, MTRJ connectors, E2000 connectors, etc. Due to low cost-benefit, SC connector is probably the most commonly used fiber optic connector. LC fiber optic connectors are also a commonly used fiber optic connector, especially for connection to SFP and SFP+ fiber optic transceivers. FC connector is mostly used in single-mode and is relatively rare in multimode fiber. Complex designs and metal housing makes it more expensive. ST fiber optic connectors are typically used in long and short-range applications such as campus and architectural multimode fiber applications, enterprise network environments, and military applications.

Choosing the appropriate connector for a fiber network depends on things such as network design and function. HYC(HYC Co., Ltd)offers a variety of fiber optic connectors of various specifications and types, including SC, FC, LC, ST, MPO, MTP and so on.

How to reverse the polarity of LC uniboot connector?

As we all know, the normal cabling uses a single fiber connector to maintain the polarity requirement. “B” sends the signal while “A” receives the signal. However, there are two types of duplex patch cord to complete serial duplex connection, “A-to-B” or “A-to-A”, which is depending on the polarity method.

Traditional LC optical fiber patch cord has great limitations in realizing polarity conversion. It requires not only auxiliary tools, but also special attention to the direction of polarity conversion, which is easily caused in failed termination.

The lc uniboot connector option includes an easy polarity revisable feature that provides quick and easy polarity changes in the field. Innovatively set the two plugs of the fiber optic connector to be interchangeable. Easily strip the boot and reverse the polarity. To reverse polarity, you just need three steps.

Step 1
Strip the boot and the outer housing

Firstly, use the right hand to hold the front housing of the connector. The hand can not touch the end face of the ferrule. Then pull out the tail sleeve of the connector with left hand. The left thumb and the middle finger pinch the outer frame,and the index finger nails hold the outer frame shrapnel.

Step 2
Revise the polarity

When the shrapnel opens out, hold the frame front cover with your right hand and pull it forward, and then revise the AB polarity.

Step 3
Relocate the boot and the outer housing

After the revise the polarity, relocate the outer frame and boot in order from the back.

The LC uniboot fiber optic connector eliminate the need for tools when making the polarity change. No tools are needed during the whole process.

A LC uniboot fiber connector with push-pull tab makes it much easier to release the connector. With this design, the technician is able to finish the installing and removing procedures with only one hand and no additional tool are needed. It is ideal for ultra high density cabling.

HYC’s LC Uniboot connectors offer the best solution for high-density applications, Data centers, Private Networks and premise installations.

Article from HYC Blog.

High Density MPO Connector Available for 400G

With the widespread deployment of data centers, the demand for 400G solutions is growing. The rapid increase in the number of network links in the data centers can cause the data center of conventional fiber cabling to become cramped and difficult to manage.  To solve this problem, data centers must obtain ultra-density to accommodate all the cabling used in the cabling. The MPO connector is designed to meet this high bandwidth requirement and meet the 400G high-speed transmission requirements.

MPO (Multi Push On) is a multi-core fiber connector type. It usually has 12 core fibers arranged in a row. A MPO connector can supports one or more rows of fibers. MPO connectors support higher bandwidth and higher density applications with 12 to 48 fiber count, which also can reach 72 or 96 in some limited applications.

MPO has many fibers in a single connector, so it reduces the amount of time required to connect fibers. Same size as SC connector, MPO connector can accommodate multi optical fibers, providing the same times the density. This flexibility basically gives you a backbone cabling system that can be adapted to any technology change or connector change in the future.

This HYC’s MPO connector, comes with SM,SMLL,MM,MMLL,8C,12C, 24C,regular force spring, high force spring for your choice. Its patented push-pull tab design provides quick and easy connection, and is also well-suited for high-density, high-traffic applications. The Push-pull tab offers maximum accessibility in high density installations; install or remove with one hand without needing additional tools.

Many applications are pursuing the high bandwidth throughput, therefore using high-density patching is inevitable. MPO connector has been widely used in data centers, telecom network, Ethernet network, and Optical communication equipment.

High Density Solution - LC Uniboot Connector

With the increasing demand for data center and bandwidth, effective cable management is a real issue. How to build more optical fiber cables in limited space is becoming a challenge for data center managers.

For data center managers, convenient management and space saving are really important in high-density cabling. LC Uniboot connector is especially designed and manufactured for better airflow and cable management in high density applications.What are the benefits of LC Uniboot connector?

Compact design to save space
Combining two fibers into a single jacket can save up to half the patching cable space compared to traditional LC duplex fiber patch cords.

Push-pull tab design
For data center administrators, it can be challenged to insert and disconnect patch cords especially in a high density environment. The push-pull tab design of LC Uniboot connector makes for easy removal of the assembly without disturbing the neighbouring ports, which offers maximum accessibility in high-density installations. With this design, the technician is able to finish the installing and removing procedures with only one hand and no additional tool are needed. What’s more, half-surround tab end avoid the cable ganged each other.

Easy Polarity Revisable
The traditional LC connector uses two jumper independent connections. If you want to change the polarity of the transmission and reception, you need to change the entire wiring system. It is difficult to do that and prone to failure. The uniboot option includes a reversing polarity feature that provides quick and easy polarity changes in the field. Polarity changes can be made in the field quickly, without the use of tools, to the correct fiber mapping polarity.

The compact design and easy polarity reversible function of the LC Uniboot Connector makes managing cable systems simpler.