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Fiber Optic in Basics: Cable, Fabric, Converter, and more!

Fiber Optic1

Glass and plastic are the two most common materials to make optical fibers. Most are about the size of a human hair and can extend for hundreds of kilometers. A signal can be imposed on the center of the fiber, which transmits light from one end to the other.
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What Is The Fiber Optic?

The advantages of fiber optics outweigh the disadvantages of metallic conductors in many cases. Broadband is their most significant advantage. Even a coaxial conductor can’t convey a signal that includes as much information due to the wavelength of light as a metallic conductor. Among the other advantages are:

Electrical Isolation

A grounding connection is not required for fiber optics. Ground loops are eliminated because both the transmitter and receiver are isolated from each other. Sparks or electrical shocks will not be a problem, as well.

Freedom from EMI

Fiber optics are immune to electromagnetic interference (EMI), and they emit no radiation themselves to cause other interference.

Low Power Loss

This permits longer cable runs and fewer repeater amplifiers.

Lighter and Smaller

Fiber weighs less and needs less space than metallic conductors with equivalent signal-carrying capacity.
Copper wire is about 13 times heavier. Fiber also is easier to install and requires less duct space.


For example, fiber optics can transmit light from a remote source to a detector to measure pressure, temperature, or spectrum information. Strain, pressure, electrical resistance, and pH can be measured with the fiber directly as a transducer. At the opposite end of the fiber, variations in light intensity, phase, and polarization can be detected due to environmental changes.

Power Delivery

High levels of power can be delivered using optical fibers for laser cutting, welding, marking, and drilling.


Endoscopes can illuminate difficult-to-reach places, such as inside the human body, with a light source attached to a bundle of fibers. They can also be utilized as a sign or just as a decorative light as a bonus.

An optical fiber consists of a core, cladding, and coating.

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The core, the cladding, and the outer coating of optical fiber all revolve around one another. Glass or plastic are the most common core materials. Still, different materials can be used based on the intended transmission range.

The core is the component of the fiber that transmits light. The cladding is typically formed of the same material as the core but with a lower refractive index (usually about 1 percent lower). Because of the index difference, total internal reflection occurs at the index border along the length of the fiber, preventing light from escaping through the sidewalls.

A light beam is twisted or refracted as it passes over an interface between two materials with varying indices of refraction.

The coating is often composed of one or more layers of plastic to shield the fiber from the elements. For further protection, metallic sheaths may be applied to the coating.

Keep on reading:Fiber Optic Patch Cords

What Is The Fiber Optic Cable?

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Rather than using copper wires, fiber-optic cables use glass fibers enclosed in an insulating sheath. They’re made for high-speed, long-distance data transmission and networking. Fiber-optic lines have higher bandwidth and can carry data over longer distances than traditional wired cables. Cable television and telephone services around the world rely on fiber-optic connections.

A fiber optic cable is made up of strands of Glass that are each no thicker than a human hair. All of this light goes through the heart of each strand. Light is reflected from the cladding into the core, reducing signal loss and allowing the light to flow around the bends in the cable.

The two most popular optical fibers in use today are single-mode and multi-mode. There are two types of optical fiber lines: single-mode and multi-mode.

In single-mode optical fiber networks, Wave Division Multiplexing (WDM) is widely employed to increase the data that a single optical fiber can carry. WDM, which multiplexes and demultiplexes light of various wavelengths, allows a single light pulse to convey multiple communication streams.

There are numerous advantages of using fiber optic cables:
Fiber optics has several advantages over long-distance copper wiring.
Fiber optics may convey more information. Fiber-optic cables can easily exceed copper cables of the same thickness in terms of network bandwidth. The standard for fiber optics is Gigabit Ethernet (Gigabit Ethernet).

Because light can travel across a fiber connection for a much wider distance without losing its power, signal boosters aren’t as necessary.

Fiber optic cable is less susceptible to interference. If a copper network cable is not insulated, electromagnetic interference can cause harm to it. Even insulated wires nearby can cause interference. Therefore it’s essential to have more than just shielding. Because of the way they are constructed, fiber optic cables are almost always free of these drawbacks.

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What Is The Fiber Optic Fabric?

This form of cloth, based on optical fibers or LED lights, is referred to as fiber-optic fabric. In creating fiber optic fabrics, Philips was a pioneering global electronics company. Fiber optic cloth emits a warmglow in any hue when powered by 35V batteries. Custom designs allow patterns or images to be woven into the material, allowing for a wide range of densities.

Because it is a brand-new product, luminous fabric serves as an excellent case study in product economics and sociology.
Fiber optic cables are made of glass, making it easy to focus the light that travels through them. Fiber optic cables are immune to electromagnetic interference, unlike metal cables. The fiber optic aspect of the cable enables it to transport data in the form of light.

Internet infrastructure uses optical fibers, which transmit data using light rather than electricity. The high bandwidth and high capacity data transfer that fiber optic cables give per unit time is another advantage of employing them for short distances.

Allowing data transmissions to travel over longer distances without degradation, these cables are less sensitive to electromagnetic interference and disturbances. The fiber cable’s core and sheath are the most critical parts. A weaker light-refracting material in the sheath causes the light beam sent from the core to be reflected and zigzag towards its destination.

Fiber optic cable comes in two flavors: multi-mode and single-mode. Multi-Mode fiber cable has a thicker core than Single Mode fiber cable. It’s possible to transmit more than one light simultaneously with multi mode fibers, commonly found in fiber optic fabric and utilized for short-distance transmission. One pulse of light is needed to carry information across a single-mode fiber cable, which may go far further than a multi-mode cable. A fiber cable’s optical qualities can be broken down into five categories: Data can reach these distances depending on its transmission speed.

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Fiber optic converter

A fiber optic media converter allows the connection of otherwise incompatible media types such as twisted pair and fiber optic cabling. Networks have become increasingly diversified with the introduction of fiber optic media converters in 1997. Interconnecting copper-based, structured cabling systems like LANs (Local Area Networks) with fiber optic cable systems is possible with a fiber optic media converter. A generic media converter includes a power supply and two data transceivers. Each transceiver has a unique set of connectors that work with a specific media type. While the other kind of media goes, a new sort of media arrives. This tool can make an optical fiber connection between copper switches.

Fiber optic patch cable

A fiber optic patch cable’s low refractive index coating is reinforced with aramid yarns, which are subsequently encased in a protective jacket. Optical signals can travel great distances with a minimal loss because of the core’s transparency. The coating’s low refractive index reduces signal loss by reflecting light into the core. The aramid strands and outer jacket protect the core and coating.

Patch cables are used in CATV (cable television), telecommunications networks, computer fiber networks, and fiber test equipment. FTH (Fiber to the Home), LANs, Fiber Optic Sensors, and other related fields of application are included in this category.

Fiber optic patch cord

Depending on the transmission medium (short or long distance), the connector construction, and the inserted core cover construction, patch cords can be classed.
Single-mode fiber has a more extended transmission range and is often yellow with a blue connection. A multi-mode fiber optic cable is typically orange or gray, with a cream or black connector and a shorter transmission distance.

It is utilized in SARFT and early CATV and is flat. The core cover of an APC connector is inserted at an angle of approximately 30 degrees (plus or minus 5 degrees). UPC polish is intended to decrease a connector’s back reflection.

For PC back reflection measurements, the industry norm is 40 dB, while for UPC back reflection measurements, the standard is 50 dB. An APC may be required if even less back reflection is needed. The ferrule of an APC connector is cut at an 8o angle. The green color of these connectors makes them easily recognizable. A polished APC connector must meet an industry standard of 60 dB. Even when detached, APC fiber ends have a little back reflection. Fiber patch cords that are armored.

The fiberglass inside an armored fiber optic patch wire is shielded by a flexible stainless steel tube tucked inside the outer jacket. The standard features of a patch cord are retained, but the cable is substantially more robust. Even if an adult walks on it, it will not be destroyed and is resistant to rodents. Fiber optic patch cords that are unable to bend.

FTTH makes extensive use of bend-insensitive fiber patch cords. Stress and bending are not a problem for the fiber. Several fibers are insensitive to bends in the single mode world, including G657A1 through G657B3. Patch cord for mode-conditioning.

It is necessary to use while connecting Gigabit 1000 Base-LX routers and switches to preexisting multi-mode cable infrastructure. In contrast to the existing multi-mode network, the transceiver modules launch single-mode 1300 nm signals exclusively.

It is possible to confuse receivers at the opposite end of a fiber when a single-mode laser is launched into the center of a multi-mode fiber. Gigabit Ethernet system distances are constrained by Differential Mode Delay (DMD). A mode-conditioning patch cord eliminates these numerous signals by angling the single-mode launch away from the center of the multi-mode fiber core. When a multi-mode light-emitting diode (LED) launch is used, the broadcast signal is similar to an offset launch.

Splitter For Fiber Optic PLC

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An optical power management device known as a Fiber Optic PLC Splitter is made utilizing silica waveguide technology.

The compact size, high dependability, and broad operating wavelength range are among the features. 1xN and 2xN PLC Fiber Splitter Products by Hopelink include, for example, 1×4, 2X16, 2X32, and 2X64 PLC splitters. Depending on the application, a variety of Fiber Optic PLC Splitters are available. These include Bare Fiber PLC Splitter, Mini Blockless PLC Splitter, Fanout PLC Splitter, ABS BOX PLC Splitter, LGX Box PLC Splitter, Mini plug-in PLC Splitter, Rack Mount PLC Splitter. Our more competitive product is also available if you’re looking for similar FBT splitter options.

What Is The Fiber Optic Closure?

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Closed-loop splicing of optical cables is made more accessible using fiber optic closures, sometimes known as “fiber optic splicing closure” devices. The fiber optic closure connects and stores optical fibers securely outside or inside. Due to their high mechanical strength they can protect the fiber joint and the fiber cables from the hostile environment, ensuring the joints are not harmed.

Types of Fiber Optic Closure

When it comes to your network’s security, it doesn’t matter how big or complex it is or how many different sorts of devices you have. To safeguard their networks, customers can select from various fiber optic closures available on the market.

Flat or cylindrical cases are the best analogy for horizontal type fiber closures. Fiber splice closures of this sort are the most typically utilized in aerials and underground installations. Fiber optic splice trays are commonly seen in horizontal fiber optic closures to protect and accommodate fiber optic splices.

Distinctive fiber optic closure designs require varied fiber splice tray designs and fiber counts. Flat fiber splice closures typically have a 12 or 24 fiber count.

Splice closures for horizontal fiber optics are designed to withstand water and dust. Because they are often composed of high tensile construction plastic, they are very adaptable and compression resistant. They must be held firmly if mounted to a pole or hung from wiring to avoid damage from the weather and wind.

The 96-fiber horizontal fiber optic splice closure can be seen in the image below (right). Two input and two output ports allow 96 fiber splices to be connected. With a 24-fiber splice tray per tray, four of these are housed inside the fiber closure.

Because it resembles a dome, vertical fiber optic closure is also known as fiber dome closure or dome fiber optic splice closure. The dome shape allows it to be buried in many applications, but it can also be utilized above ground.

Many devices and configurations are available for vertical fiber optic splice closure due to increasing network demands. For today’s fiber-optic networks, high-capacity variants and variations in the number of splicing trays are also on the market. Additionally, the number of inlet/outlet ports of the dome fiber optic closure varies depending on the application. Due to its underground usage, the dome fiber optic splice closure requires high-level sealing and waterproof technologies. In addition, underground closures require a barrier that keeps insects and debris out.

What Is A Fiber Optic Cabling System?

Fiber Optic Cable

The integrated cabling system is a cabling network combining voice, data, image, and multimedia service equipment on a standard cabling system and a single wiring system composed of common accessories to realize the interconnection of signals among the integrated communication network, information network, and control network. In the integrated wiring system, the optical cable communication system is a communication method using light waves as the carrier and optical fiber as the transmission medium. The leading roles of this communication method are a light source, optical fiber, and photoelectric conversion module.

What Is A Fiber Optic Cabling System?

MT-1092 gyta53 fiber optic cable

Optical fiber is the abbreviation of optical fiber, which is a delicate and flexible optical transmission medium made of quartz, rubber-jacketed silicon, and plastic materials. For the optical signal to be transmitted effectively, the outer layer of this fiber must be coated with an opaque material with a lower refractive index than the fiber core, which is called cladding.

What is optical fiber? Optical fiber is short for Optical Fiber. It is an excellent fibrous material formed from quartz glass or plastic, cylindrical in shape, with a diameter of about 9-50 microns. Optical fiber consists of a core, a cladding, and a coating layer in daily use.

The core is located in the center of the fiber, diameter of 4-50 μm. The core is composed of high-purity silica (currently, quartz optical fiber, multi-component glass fiber, all-plastic fiber, and fluoride fiber are also widely used). In addition, a minimal amount of dopants (such as germanium dioxide and phosphorus pentoxide) is to properly improve the refractive index of the core to light for the transmission of optical signals.

The cladding layer is located around the fiber core, with a diameter of 125 μm, and its composition is also high-purity silica containing tiny amounts of dopants. Here, the role of the dopant (e.g., boron trioxide) is to adequately reduce the refractive index of the cladding to light so that it is slightly lower than the refractive index of the core, i.e., the refractive index of the body is greater than the refractive index of the cladding (which is the key to the fiber structure). It allows the optical signal to be enclosed in the core for transmission.

The outermost layer of the fiber is the coating layer, including the primary coating layer, the buffer layer, and the second coating layer.

The primary coating layer generally uses acrylic, silicone, or rubber materials.

The buffer layer is generally a good performance filler paste; the secondary coating layer typically uses polypropylene or nylon and other polymers.

The role of the coating layer is to protect the fiber from water vapor erosion and mechanical abrasion while increasing the mechanical strength and bendability of the thread, thereby extending the life of the fiber.

The outer diameter of the coated fiber is generally about 2.5 mm. Since the refractive index of the core is designed to be slightly larger than the cladding, the laser signal is enclosed in the core and propagates in the fully reflective waveguide state.

What Is Fiber Optic Cable?

MT-1096 ADSS fiber optical cable manufacturer single sheath double sheath 4-core span

In an optical transmission system, optical fiber cannot be used directly in actual wiring because the coating layer is very thin, not easy to lay and maintain, and easy to damage, so optical fiber cable is used instead. Fiber optic cable can be regarded as a cable made of multiple optical fibers reprocessed. Depending on the occasion of use, fiber optic cable can be divided into indoor fiber optic cable and outdoor fiber optic cable. Indoor fiber optic cable is one or several optical fibers loosely placed in a particular plastic casing and add a tensile cotton thread to form a fiber optic cable and use.

Outdoor fiber optic cables are made by coating several optical fibers with grease material and placing them inside a plastic sleeve, armored with aluminum tape in the outer layer, adding tensile steel wire, injecting waterproof gel, and finally adding a rubber sheath to form a fiber optic cable. Currently on the market are commonly used single-core skin cables, four core, 12 core, 48 core, and another optical fiber cable.

What Is A Fiber Optic Connection Device?

MT-1010 48 core SC/UPC Duplex ODF

A fiber optic link can properly transmit signals, in addition to the fiber itself, but also need a variety of different connection hardware as support and renewal, some of which are used for fiber optic connection and others for pipeline finishing.

Fiber optic wiring equipment (ODF) is used for termination of fiber optic cable at both ends and distribution of fiber, with fiber optic cable fixed, protection and grounding, fiber and pigtail fusion, deployment of optical paths, redundant fiber management place, can be very convenient to achieve fiber optic link fusion, patching, scheduling, and other functions.

A fiber Connector (Fiber Connector) terminates the optical fiber so that the thread can be connected to the corresponding device or adapter.

According to the different connectors, fiber optic connectors are divided into ST, SC, LC, FC, etc., and miniaturized (SFF) fiber optic connectors are developed to meet the needs of users to connect high-density connectors, which have a great tendency to replace the current popular connectors. Therefore, miniaturization is the development direction of fiber optic connectors.

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How To Connect Fiber Optic?

After the fiber is laid, to make it work properly and carry optical signals, it must be terminated to form a complete fiber optic transmission link. Fiber optic links will have multiple connections, including direct fiber splice points, connector terminations, and connector interconnections.

Fiber optic connection methods can be broadly divided into permanent, emergency, and active.

MT-1305 Fiber optic distribution 288 core optical cross connection distribution telecom street cabinet

Permanent fiber optic connection (also called thermal fusion)

This connection is made by melting and connecting the connection points of even optical fibers using electrical discharge. It is generally used in long-distance splicing, permanent or semi-permanent fixed connections. The main feature is that the connection attenuation is the lowest among all connection methods, with typical values of 0.01-0.03 dB/point. However, the connection requires special equipment (fusion machine) and professional personnel to operate, and the connection point also needs to be protected by a particular container.

emergency connection (also called) cold fusion

Emergency connection is mainly mechanical and chemical methods. The two optical fibers are fixed and bonded together. The main feature of this method is that the connection is fast and reliable, and the typical attenuation of the connection is 0.1 to 0.3 dB/point. However, the connection point will be unstable for long-term use, and the attenuation will increase significantly, so it can only be used for a short period in an emergency.

into the end of the active connection

At the end of the active connection are the use of a variety of fiber optic connection devices (plug and socket), the site and site or site, and a fiber optic cable connected to a method. This method is flexible, simple, convenient, and reliable and is mainly used in the network cabling in the front-end room. Its typical attenuation is 1dB/joint.

How Is Fiber Optic Splicing Performed?

24 core ABS Fiber Optic Splicing Tray

Fiber optic renewal is a permanent connection between two sections of optical fiber. Depending on the nature of the fiber, it is divided into the renewal between two fibers and the connection of one fiber and one pigtail.

Depending on the connection method, it can be further divided into the mechanical connection (cold splice) method and machine fusion (hot fusion) method. The mechanical connection combines two cleaned and cut optical fibers that are mechanically joined together.

This cold connection is easy to operate and less expensive. Still, the disadvantage is that the loss of the fiber after the connection is relatively large compared to hot fusion, and the failure rate is higher in the future use of the process.

What Is A Fiber Optic Termination Connector?

MT-1002 Wall Mounted Metal Fiber Optic Termination Box with key

Fiber optic termination connectors are mainly used for the renewal of connection parts that require multiple unplugging, non-permanent fiber optic connections. They are used in the process of making fiber optic patch cords or pigtails, which are inefficient to produce on site, and the loss and accuracy are not well controlled. Therefore, the integrated cabling site now rarely uses fiber optic termination connectors but the choice of finished patch cords and pigtails.

Fiber Optic Connector Interconnection

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Fiber optic connector interconnection refers to connecting two fibers fused with pigtails through adapters installed in fiber optic patch panels and fiber optic sockets.

The two pigtails are inserted into each end of the fiber adapter. The ceramic part of the two pigtails is connected through precise control of the opening and distance between the adapters to achieve more minor losses. It is also possible to insert one end of a fiber optic patch cable into the adapter and another into the network switching port, which is bound to occur in actual network cabling system projects.

Polarity Of Fiber Optic Connection

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The fiber optic transmission process is carried out by an injected laser diode (LID, used in single-mode fiber) or light-emitting diode (LED, used in multimode fiber) emitting an optical signal that travels along the fiber core media. After the incident light enters the fiber through the fiber end face, a portion of the light travels in a straight line in line with the axial direction, while another part of the fiber is projected onto the intersection of the core and the cladding.

As seen from above, in an efficient fiber optic cabling system, the signal of light is transmitted in one direction, which is the simplex mode. When laying fiber optic cables in optical system engineering, it is necessary to ensure that there are at least two cores of fiber optic cables at an information point, one of which is used for sending signals and the other for receiving alerts.

If sending to send and receiving to receive, the optical system will not work, so the direction of signal transmission in this fiber should be determined before installing the fiber optic cable.

The fiber optic connector is equipped with simplex and duplex fiber optic patch cords in the integrated cabling system.

As the construction of the permanent link is done by professional technicians, it is appropriate to use simplex fiber optic connectors at the horizontal fiber optic cable end, while on the outside of the panel, as fiber optic patch cords are plugged and unplugged by non-professional users themselves, it is appropriate to use duplex fiber optic connectors to ensure the correct polarity of the fiber connection.

Fiber Optic Fusion Splicing Failure And Measures To Improve Quality

MT-8514 splicing Fusion Splicing Optical fiber splicing machine

As in the fiber optic connection process, the standard method is hot fusion by fiber optic fusion machine or cold splicing using fiber optic quick connector. The following describes the causes of failure and factors affecting the loss of fiber optic connection.

Fiber Optic Fusion Splicer Abnormal information

In the fiber optic fusion process, improper operation or fiber problems cause the fusion splicer error and display fault-related information. Then the technician needs to analyze the cause of the fault and take relevant measures to eliminate the defect.

MT-8524 T45 Fusion Splicer Fiber Optic Splicing Machine

Abnormal setting and out of travel

The fault causes: fiber in the V-slot placement error; fiber cutting length is not reasonable; fusion splicer lens after the release mirror dirty.

Measures: reposition the fiber to the correct position; re-strip, cut the fiber; clean the fiber fusion splicer lens, etc.

After the fusion splicer discharge, the fiber shows a fusion bubble

The fault causes poor fiber end cutting, end rupture or dirty, and short pre-fusion time.

Measures: check the fiber cutting knife, re-prepare the fiber; clean the fiber; adjust the pre-melt time of the fusion splicer.

Poor fiber end face quality

Cause of failure: fiber cutting angle is greater than the threshold value; fiber surface, lens dirty; clean discharge function off time is too short.

Measures: Check the cutting knife and re-prepare the fiber. Clean the fiber and fusion splicer lens; increase the cleaning and discharging time.

Fiber Connection Loss

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The loss of optical fiber is the attenuation of light per unit fiber length in dB/km.

First, when the optical signal is transmitted in the optical fiber, the absorption and scattering will cause a reduction in optical power due to the physical properties of light itself.

Secondly, the intrinsic factor of the fiber is also the cause of fiber loss, which is caused by changes in the fiber and can lead to inherent loss.

Once an optical fiber is produced, its intrinsic loss is determined.

In summary, the loss of an optical fiber is the sum of the loss of the fiber transmission signal and the fiber connection’s failure. Here, only the loss caused by the fiber connection to the optical signal transmitted by the fiber is highlighted.

The following non-intrinsic factors mainly cause fiber loss.

(1)fiber end separation: this situation mainly occurs in the use of fiber optic quick connector for cold connection of optical fiber, due to the activity of the connector connection is not good, it is easy to cause the fiber end face and connector is not wholly close fit contact, leaving a gap in the middle, resulting in a significant connection loss.

(2) fiber end-face tilt: refers to the fiber optic splicing, fiber end-face tilt, resulting in cable loss. When the fiber tangent is 1 degree, about 0.6dB of splicing loss, if the need for loss ≤ 0.1dB, the tilt angle should be less than 0.3 degrees.

Measures To Improve The Quality Of Fiber Optic Fusion Splicing

FTTH wholesale T45 fusion splicer machine Fiber Optic Splicing Machine

To reduce the loss of fiber optic transmission signal throughout while using long-distance fiber optic cable as much as possible, it is also vital to improve the slicing quality.

(1) Use a unified brand of optical fiber cable. In the same line as far as possible to use a suitable batch of high-quality brand fiber optic cable, so that two pairs of fusion fiber physical intrinsic characteristics of the same, and therefore the fusion of this breakpoint can make the mode field diameter of the optical signal loss is reduced to a minimum.

(2) to ensure the quality of laying fiber optic cable. In the fiber optic cable laying process, bending and playing small circles are strictly prohibited. In the cable release, the traction force should be loaded on the traction wire in the fiber optic cable and must not be added to the internal bundle of fiber optic cable. And traction force shall not exceed 80% of the allowable tension of the cable itself. The instantaneous traction force shall not exceed 100%.

Fiber Optic Construction Process Of Safety Operations

Because of the fiber optic material structure and light transmission characteristics, in the construction process, if improper operation, cutting left fiber fiber fiber debris will cause harm to the human body, and the transmitted light may be harmful to human eyes. Therefore, in the fiber optic construction project, take adequate precautions to achieve safe operation. The following specifications should be strictly observed for fiber optic cable in the specific operation process.

(1) The personnel who carry out the construction of optical fiber cable must pass the corresponding professional and technical training, understand the propagation characteristics of light, master the connection methods and techniques of optical fiber, and have good professional conduct.

No qualifications and untrained personnel are strictly prohibited from carrying out fiber optic construction. Any person is strictly forbidden to operate the optical transmission system that has been installed and used.

(2) The broken fiber optic fibers are microscopic glass needle-type fibers, which are easy to cut and enter the skin, making people feel pain. In addition, if these fragments are inhaled, they can cause more significant harm. Therefore, wearing goggles and rubber gloves during fiber optic construction is vital.

How Many Types Of Fiber Optic?

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There are many ways to classify fiber optics, such as quartz-based fiber, multi-component glass fiber, plastic-clad quartz-core fiber, all-plastic fiber, and fluoride fiber.

The mode of light transmission can be divided into multi-mode fiber (Multi-mode Fiber) and single-mode fiber (Single-mode Fiber).

The operating wavelength of the optical fiber can be divided into short-wavelength fiber, long-wavelength fiber, and ultra-long-wavelength fiber.

If classified according to the best transmission frequency window can be divided into conventional single-mode fiber and dispersion-shifted single-mode fiber.

If classified according to the refractive index distribution, it can be divided into step-type and gradient-type fibers.

Here we only focus on single-mode fiber and multi-mode fiber.

(1) single-mode fiber: single-mode fiber with a weak central glass core (core diameter is generally 9 or 10 μm) can only transmit in a single mode at a given wavelength, with the advantage of wide transmission bandwidth and large capacity.

Because only one light mode can be transmitted, its inter-mode dispersion is small and suitable for long-distance communication. Still, there is also material dispersion and waveguide dispersion, so single-mode fiber has high requirements for the spectral width and stability of the light source, i.e., the spectral width should be narrow, and the peace should be good.

Later, it was found that at 1.31 μm, the material dispersion and waveguide dispersion of single-mode fiber is positive and negative, and their sizes are equal. This means that the total distribution of single-mode fiber is zero at 1.31 μm wavelength. In terms of the loss characteristics of the fiber, 1.31 μm is a low-loss window of the fiber.

In this way, the 1.31μm wavelength region becomes an ideal operating window for fiber optic communication and is now the principal working band for practical fiber optic communication systems. The International Telecommunication Union ITU-T determined 1.31μm conventional single-mode fiber’s main parameters in the G.652 recommendation, so this fiber is also known as G.652 fiber.

(2) Multi-mode fiber: It can transmit simultaneously at a given operating wavelength in multiple modes. Multi-mode transmission, due to different ways of light communication along the line of different speeds, will produce phase differences that will lead to transmission distortion, thus making its transmission band subject.

The center glass core is thicker (50 or 62.5 μm) and can transmit various light modes. However, its inter-mode dispersion is large, which limits the frequency of transmitted digital signals, and will be more severe with the increase in distance.

Therefore, the transmission performance of multi-mode fiber is poor compared to single-mode fiber. For example, a 600MB/KM fiber has only 300MB of bandwidth at 2KM. Therefore, the transmission distance of multimode fiber is closer, usually only a few kilometers.

The fiber core size can easily distinguish single-mode and multi-mode fiber. In general, short-wave optical modules use multi-mode fiber to ensure data transmission accuracy and long-wave optical modules use single-mode fiber. Patch cords for single-mode fibers are generally indicated in yellow, with blue or green connectors and protective sleeves.

The jumper of multi-mode fiber is generally indicated in orange, or some in gray, with beige or black connectors and protective sleeves. Fiber optic patch cords at both ends of the optical module must be the same wavelength. That is to say, both lots of the fiber must be the same wavelength optical module. A simple way to distinguish is for the color of the optical module to be consistent.

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Why Do Optical Fibers Attenuate?

The main factors that cause fiber attenuation are intrinsic impurities, inhomogeneities, bending, extrusion, butt splicing, etc.

Intrinsic: the inherent loss of the fiber, including Rayleigh scattering, inherent absorption, etc.

Impurities in the fiber absorb and scatter the light propagating in the fiber, resulting in the loss.

Inhomogeneous: the loss caused by the inhomogeneous refractive index of the fiber material.

I am bending: the loss caused by the loss of light scattered within the fiber when part of the fiber is bent.

Squeeze: loss caused by the slight bend in the fiber when squeezed.

Docking: fiber butt loss, such as different axis (single-mode fiber coaxial requirements less than 0.8μm), end face and axis not perpendicular, end face not flat, butt core diameter mismatch, and poor fusion quality.

The first three factors are caused by the fiber itself and the production process, which are difficult to overcome. Human factors in use mainly cause the last three factors. Therefore, when using optical fiber, avoid excessive bending and ringing.

When fusion splicing, try to ensure that the cut end face is flat, which can reduce the light in the transmission process, and the attenuation caused by human factors. In addition, after using fiber optic patch cords, you must also use a protective sleeve to protect the fiber optic connector. Otherwise, dust and oil will damage the fiber coupling, resulting in sharp signal attenuation, as in Figure 3.

How To Test The Fiber Optic?

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The primary purpose of fiber optic inspection is to ensure the quality of the system connection and reduce the failure factors as well as the failure to find out the failure point of the fiber. There are many testing methods, mainly divided into simple manual measurement and precision instrumentation measurement.

(1) Manual simple measurement: This method is generally used to detect the fiber optic through and through quickly and to distinguish the fiber made during construction. It is a simple light source from one end of the fiber into the visible light, from the other to observe which one is luminous to achieve. This method is easy, but it does not quantitatively measure the fiber’s attenuation and the thread’s breakpoint.

(2) Precision instrumentation measurement: Using an optical power meter or visual time domain reflectometer (OTDR) for quantitative measurement of optical fibers, the fiber’s attenuation, the connector’s attenuation, and the approximate location of the fiber breakpoint can be measured. This measurement can be used to quantitatively analyze the cause of fiber optic network failures or evaluate fiber optic products.


Through the above introduction, we know that because the strength of a single fiber is meager and inconvenient to lay, so the single fiber is wrapped with a thin plastic jacket to protect the envelope. After the encapsulation of the fiber, according to different specifications tied into bundles, it becomes easy to lay the construction of fiber optic cable.

Optical fiber communication system to light waves as the carrier, optical fiber as the transmission medium of communication, by analyzing the performance of the complete fiber optic transmission link, using fiber optic splicing, fiber termination, fiber connector interconnection three ways to complete the wiring of the fiber optic network, and give measures to deal with fiber optic fusion failure and improve the quality, and finally its safety operation steps are summarized.