An optical fiber is a fiber made of glass or plastic, while a fiber optic cable is a type of communication cable consisting of an optical fiber, a plastic protective sleeve, and a plastic sheath. Fiber optic cable is a new generation of transmission medium, which can carry out long-distance signal transmission. Compared with traditional network transmission methods, fiber optic communication has the advantages of large capacity, long distance, and good confidentiality. When choosing fiber optic cables, you should pay attention to selecting the appropriate models and distinguishing the pros and cons of those products. So do you know how to choose the model and specification of fiber optic cable for home use? And do you know how to connect and lay fiber optic cables? Let’s take a look below!
What Is Optical Fiber?
1. What does an optical fiber look like?
The construction of an optical fiber includes a core and cladding, usually in a cylindrical shape. At present, the optical fiber used for communication on the market is basically silica optical fiber. The main component of this kind of optical fiber is high-purity silica glass, namely silicon dioxide (SiO2).
2. Optical fiber communication principle
Optical fiber communication is a communication method in which light waves are used as information carriers and optical fibers are used as transmission media.
To put it simply, at the sending end, the transmitted information (such as voice) must first be converted into an electrical signal, and then modulated onto the laser beam emitted by the laser, so that the intensity of the light changes with the amplitude (frequency) of the electrical signal, and sent out via optical fiber. At the receiving end, the detector converts the optical signal into an electrical signal after receiving it, and restores the original information after demodulation.
3. The development history of optical fiber communication
In 1880, Alexander Murray invented the “optical phone” for optical beam communication transmission. Seven years later, British scientist Charles Vernon Boys pulled out the first optical fiber in the laboratory. In 1966, Chinese-British scholar Gao Kun pointed out the possibility and technical approach of using optical fiber for information transmission, which laid the foundation for modern optical communication. Therefore, Gao Kun is also known as “the father of modern optical fiber”. With the further development of Internet technology, the optical fiber and cable industry will usher in broader development opportunities.
4. What are the main uses of optical fiber?
Optical fiber has the advantages of large communication capacity, long relay distance, good confidentiality performance, strong adaptability, no fear of external electromagnetic field interference, and corrosion resistance. In addition to being used in the communication industry, optical fibers are also widely used in sensor applications, medical applications, and downhole detection technology.
5. Classification and specification of optical fiber
- Multimode optical fiber: The diameter of the transmission part of the multimode optical fiber is 50 micrometers, and the outer diameter is 125 micrometers. It can transmit multiple modes of light, and is suitable for short-distance transmission with a light wavelength of 850nm1300nm.
- Single-mode optical fiber: The diameter of the single-mode optical fiber transmission part is 80 micrometers, and the outer diameter is 125 micrometers. It can only transmit one mode of light, and is suitable for long-distance communication with light wavelengths of 1260nm-1640nm.
What Is Fiber Optic Cable?
Structural characteristics of fiber optic cable
A fiber optic cable is a cable made of one or more optical fibers or optical fiber bundles that meets chemical, mechanical, and environmental characteristics. It is generally composed of three parts: a cable core, a strengthening element, and a sheath.
What is the fiber optic cable used for?
The main function of the fiber optic cable is to transmit optical signals. The fiber optic cable transmission signal has the advantages of wide frequency bandwidth, low loss, strong anti-interference ability, and high fidelity.
Types of fiber optic cable
- Stranded fiber optic cable: Stranded fiber optic cable is made of multiple sleeves containing optical fibers around the central strengthening member to form a round cable core, which is suitable for long-distance communication and inter-office communication.
- Slotted core fiber optic cable: Slotted core fiber optic cable is a kind of optical cable that puts the optical fiber into the groove of the cylinder, and is suitable for use as a transmission feeder in the access network, inter-office relay, and cable television network.
- Central beam-tube fiber optic cable: The beam-tube fiber optic cable uses a loose tube as the cable core, and the strengthening members of the cable are distributed around the loose tube. This kind of fiber optic cable has specifications such as 4 cores, 6 cores, 8 cores, 12 cores, and 24 cores, and the scope of application of fiber optic cable with different specifications is also different.
- Ribbon fiber optic cable: Ribbon structure fiber optic cable is an optical cable that puts the ribbon optical fiber unit into a groove or a loose tube to form a bracket or layered structure, and is widely used in large urban area networks in cities. In environments such as main optical cables of the access network, it plays an important role in realizing fiber-to-community (or roadside, building).
What is the difference between fiber optic cable and optical fiber?
Optical fiber is the light-conducting fiber in the fiber optic cable and is a part of the optical cable. Generally, it is not necessary to strictly distinguish between the two in engineering applications.
What is the difference between a home network cable and an optical fiber?
For ordinary broadband users, FTTH means installing optical fiber into the user’s home. Connect the optical fiber to the optical modem, and then connect the router computer and other equipment to the Internet through the optical modem.
The network cable is usually installed in the corridor of the community through the operator’s switch, and a network cable is connected to the user’s home through the switch interface. Users connect to this network cable through routers and other Internet access devices to access the Internet at home.
What is the difference between fiber optic and broadband?
Optical fiber transmits signals in the form of light pulses, and the speed is very fast, generally reaching more than one gigabit per second. Broadband is generally made of copper telephone cables, and the electrical signal transmission is completed through dial-up Internet access, which is much slower than optical fiber Internet access.
Fiber Optic Cables’ Selection Guide
The price of fiber optic cable
Different structures and different types of optical cables have different prices. The price of an ordinary indoor single-mode optical cable may only cost $1 per meter, while the price of a 10gb indoor optical cable may cost $10 per meter.
How to choose the model and specification of fiber optic cable for home use?
- Single-mode or multi-mode: Single-mode fiber is suitable for long-distance transmission, multi-mode fiber is suitable for medium and short-distance optical fiber communication, and dual-mode fiber is generally used for household use.
- Length and wire diameter: The length and wire diameter of the fiber optic cable need to be selected according to the actual use requirements. It is recommended to buy the fiber optic cables as long as possible to avoid insufficient use in the future.
Selection principles of fiber optic cable
- Look at the type: When choosing a fiber optic cable, you should choose the type according to the actual use. For example, if it is used for long-distance communication, it is more suitable to use a twisted optical cable.
- Depending on the environment: When laying cables vertically in the building, you can choose layer-twisted fiber optic cables; when wiring horizontally, you can choose branchable fiber optic cables; when laying outdoor optical cables directly, you should choose armored fiber optic cables.
Fiber Optic Cable’s Connection Laying Guide
Fiber optic cable‘s access method
Permanent connection (thermal fusion splicing): thermal fusion splicing is the mainstream optical fiber construction method in the world. It uses the high-voltage arc of the optical fiber fusion splicer to melt the two optical fibers and connect them. It is suitable for long-distance communication. It is also suitable for short-distance optical fiber laying construction.
Emergency connection (cold mechanical fiber splicing): The cold mechanical fiber splicing is to use optical fiber cold splicers to connect the optical fibers or connect them to optical communication equipment. The cold mechanical connection method is easy to operate and suitable for field work, but it needs to be prepared multiple fiber optic connectors.
Fiber optic cable access devices
1. Optical fiber transceiver: Optical fiber transceiver is a device used to realize the conversion between optical signal and electrical signal. It is generally used in the actual network where the Ethernet cable cannot be covered and optical fiber must be used to extend the transmission distance.
2. Optical fiber distribution frame: Optical fiber distribution frame is a wiring connection device between optical cable and optical communication equipment or between optical communication equipment. It is generally installed on the rack, and small ones can also be directly installed on the wall.
3. Network switch: A network switch is a high-speed network transmission relay device, which has the advantages of fast speed and strong anti-interference ability.
4. Optical fiber connector: Optical fiber connectors are also called optical fiber jumpers. Installing optical fiber connectors at both ends of the optical cable can realize the active connection of the optical path.
5. Optical cable splicing box: Optical cable splicing box is a splicing device that connects two or more optical cables together and has the function of protecting components. The quality of the optical cable splice box directly affects the quality of the optical cable and the service life of the optical cable.
Fiber optic installation method
1. How to connect the optical cable to the router?
Fiber optic cables cannot be directly connected to routers. Optical modems are required for fiber optic access to the home. The main function of optical fiber modems is to convert signals. Connect the optical fiber to an optical modem, then connect the router to the optical modem, and set up the router to connect to the Internet.
2. How to connect the optical cable to the network switch?
Fiber optic cable must first enter the optical transceiver (PDH) for signal conversion, and then it can be connected to the coaxial cable after coming out of the pigtail, and then connected to the switch through the RJ45 or BNC interface.
3. How to connect the optical cable to the computer?
The fiber optic cable is generally not directly connected to the computer, because the home computer is rarely equipped with a dedicated optical fiber network card, we can first connect the fiber optic cable to an optical modem, and then connect the optical modem to the computer.
4. How to reconnect the optical cable if it is broken?
If the fiber optic cable is broken, it can be reconnected by fusion splicing. It is recommended to find professional technicians for fusion splicing, because the price of optical fiber fusion splicer and optical fiber cutting machine is expensive. Moreover, the requirements for operating technology are relatively high.
What should be paid attention to when fiber optic cabling?
Before fiber optic wiring, complete design and construction drawings must be prepared, and strictly trained technicians should be selected to perform fiber termination and maintenance.
Be careful not to put heavy pressure on the optical cable during wiring, and place the optical cable carefully to avoid abrasion and damage from hard objects.
The length of fiber optic cabling should not be too long at one time, and should be drawn from the middle to both sides during cabling. If fiber optic cabling needs to pass through walls and floors, protective plastic tubes with guards should be added to the fibers, and the tubes should be filled with flame-retardant fillers.
The laying method of fiber optic cable
Aerial fiber optic cable: Aerial fiber optic cable is an optical cable that is hung on a pole. This laying method can make use of the original overhead open wire poles, saving construction costs and shortening the construction period.
Directly buried fiber optic cable: The exterior of the directly buried optical cable must be armored with steel tape or steel wire, otherwise it cannot resist external mechanical damage, nor can it prevent soil corrosion. This laying method is not only suitable for the laying of terrestrial fiber optic cables, but also for the laying of submarine/underwater optical cables.
Pipeline fiber optic cable: Pipelines are generally laid in urban areas, and the environment for pipeline laying is relatively good, so there is no special requirement for the sheath of the optical cable, and no armor is required. The materials for making pipelines can be selected from concrete, cotton cement, steel pipes, plastic pipes, etc, according to the geography.
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