Optical fiber and Cable

I. Optical Fiber
1. Overview
The optical fiber is similar to the coaxial cable, but there is no mesh shielding layer. The center is the glass core of light transmission. In multimode optical fiber, the core diameter is 15mm ~ 50mm, roughly equivalent to the hair width of a person. The diameter of the Single-Mode Optical Fiber Core is 8mm ~ 10mm. The outside of the core is surrounded by a glass envelope with a lower refractive index than the core to keep the optical fiber inside the core. A thin plastic coat is used to protect the cover. The optical fiber is usually bundled into a bundle, and the outer casing is protected. The core is usually a double concentric cylinder with a very small cross-sectional area made of Z glass. It is brittle and easy to break, so a protective layer needs to be added. Its structure 1 is shown in.
　
Fiber cables on land are usually buried at 1 m underground and sometimes damaged by small underground animals. In the area near the coast, the fiber optic shell is buried in a trench. In deep water, they are at the bottom, and are most likely to be bitten by fish or damaged by fishing boats.
2. Classification
Optical fiber is mainly divided into the following two categories:
1) module of the transmission point
The module of the transmission point is divided into Single Mode Fiber and Multi Mode Fiber ). The diameter of the core of a single-mode optical fiber is very small. It can only be transmitted in a single mode at a given working wavelength. The transmission bandwidth and capacity are large. Multimode Optical Fiber is an optical fiber that can be transmitted simultaneously in multiple modes at a given wavelength. Compared with single-mode optical fiber, multi-mode optical fiber has poor transmission performance.
2) REFRACTIVE INDEX DISTRIBUTION
Refractive Index Distribution optical fiber can be divided into Hop-type optical fiber and gradient optical fiber. The refractive index of the hop-type fiber core and the refractive index of the protective layer are both constant. On the interface between the core and the protective layer, the refractive index changes step by step. The refractive index of the gradient fiber core decreases with the increase of radius according to a certain law, and the refractive index of the protective layer is reduced at the junction of the core and the protective layer. The refractive index of the core is almost parabolic. Refractive Index Distribution is shown in optical fiber beam transmission 2.
　
3. Connection Mode
Three optical fiber connection modes are available. First, you can connect them to the connector and insert them into the fiber optic outlet. The connection head consumes 10% to 20% of light, but it makes it easy to reconfigure the system.
Second, it can be joined mechanically. The method is to place one end of the two carefully-cut optical fibers in one casing and clamp them up. The optical fiber can be adjusted through the combination to maximize the signal. Mechanical integration takes about five minutes for trained workers to complete, and the loss of light is about 10%.
Third, the two optical fibers can be integrated to form a solid connection. The optical fiber formed by the fusion method is similar to that of a single optical fiber, but it also degrades. The three connection methods are reflected at the junction, and the reflected energy interacts with the signal.
4. Sending and receiving
Two light sources are available for use as signal sources: light-emitting diode (LED) and semiconductor laser ILD (injection laser diode ). They have different features, as shown in the following table.
　
The receiving end of the optical fiber is composed of PHOTODIODES. In the case of light, it gives a point pulse. The response time of the diode is generally 1ns, which is the reason that the data transmission rate is limited to 1 Gb/s. Thermal noise is also a problem, so the optical pulse must have enough energy to be detected. If the pulse energy is strong enough, the error rate can be reduced to a very low level.
5. Interfaces
Currently, two interfaces are used. The passive interface is formed by two cables fused to the main optical fiber. One end of the connector has a light emitting diode or laser diode used for sending ). The other end has a diode for receiving ). The connector itself is completely passive and therefore very reliable.
Another interface is called an active repeater ). The input light is converted into an electrical signal in the repeater. If the signal is weakened, it is re-amplified to the maximum intensity, then converted to light and then sent out. The computer is connected to a common copper wire that enters the signal generator. Now there is a pure optical repeater, which can run at a very high bandwidth without the need for photoelectric conversion.
Ii. Optical Cable
Optical fiber is a subtle and flexible media for transmitting beams. The optical fiber cable consists of a bundle of fiber cables. Optical Cable is the most effective transmission medium for data transmission. It has the following advantages:
(1) Wide Band.
(2) good electromagnetic insulation performance. The optical fiber cables transmit beam. Because the beam is not affected by external electromagnetic interference and does not emit signals, it is suitable for long-distance information transmission and high-security scenarios. Of course, it is inherent because the split Optical Cable needs to be regenerated and re-sent.
(3) The attenuation is small. It can be said that the signal is a constant in a long distance and within a range.
(4) Large repeater intervals can reduce the number of repeater connections throughout the channel and reduce costs. According to Bell's laboratory tests, when the data transmission rate is 119 Mbps and there is no repeater at a distance of km, the error rate is 10-8, which shows that its transmission quality is very good.
The coaxial cable and twisted pair wires need to be connected to a repeater every several thousands of meters.
In applications that use optical fiber cables to interconnect multiple minicomputers, one-way optical fiber characteristics must be considered. If bidirectional communication is required, two-strand optical fiber cables should be used. Due to the need for multi-channel transmission and multi-channel selection of light at different frequencies, an optical multi-channel converter has emerged in the communication device market. The installation of optical cables in a common computer network starts from the user's device. Because optical cables can only be transmitted in one way. To achieve bidirectional communication, optical cables must appear in pairs, one for input and one for output. Both ends of the optical cable are connected to the optical interface device.
Exercise caution when installing optical cables. When connecting each optical cable, the end should be polished and connected together with the optical interface through the electric barbecue or chemical ring chlorine process to ensure that the optical passage is not blocked. The optical fiber cannot be too tight or at a right angle.
The type of optical fiber depends on the die material (glass or plastic fiber), Core and outer size, and the size of core determines the optical transmission quality. Common optical fiber cables include:
8.3 μm core, 125 μM outer layer, single-mode.
62.5 μm core, 125 μM outer layer, multimode.
50 μm core, 125 μM outer layer, multimode.
100 μm core, 140 μm outer layer, multimode.
Iii. Optical Fiber Communication System and Its Composition
1. Optical Fiber Communication System
The optical fiber communication system uses optical fiber as the carrier and optical fiber as the transmission media. It plays a dominant role in light source, optical fiber, optical transmitter, and optical receiver.
Light source is the root cause of light waves.
Optical fiber is the conductor of Optical Waves.
The function of the optical transmitter is to generate a beam, convert an electrical signal into a light signal, and then import the optical signal into the optical fiber.
The function of an optical receiver is to receive and convert an optical signal transmitted from an optical fiber into an electrical signal, which is decoded before processing.
2. Composition
The basic structure of the optical fiber communication system is as follows:
　
The main advantages of optical fiber communication systems include:
(1) transmission bandwidth, large communication capacity.
(2) low line loss and long transmission distance.
(3) strong anti-interference ability and wide application scope.
(4) thin wire diameter, light weight.
(5) strong chemical corrosion resistance.
(6) abundant optical fiber manufacturing resources.
In network engineering, multimode optical fiber with a specification of 62.5 μm/125 μM is generally used, sometimes 100 μm/125 μM and 100 μm/140 μm optical fibers are used. Single-Mode Optical Fiber is optional when the outdoor wiring is greater than 2 km. Some of the basic features of optical fiber cables that need to be understood during integrated cabling are described in the following example. Table 1 and Table 2 are Optical Fiber Performance indicators and temperature ranges respectively.
　
　
To facilitate reading the following table, the diameter, weight, tension, and bending radius are explained as follows:
Diameter: the unit is mm.
Weight: expressed in kg/km.
Tension: the unit of tension is N (Newton ). There are two cases of tension: the maximum value is 2700N during installation, and the long-term value is 127n after installation;
Bending radius: The bending radius when the optical cable is bent.
Iv. Optical Cable Types and Mechanical Properties
1. Single-core interconnected Optical Cable
(1) Application Scope
Jumper.
Internal device connection.
Communication cabinet wiring panel.
What is the connection from the wall exit to the workstation? /Li>
· Horizontal cable pulling and direct connection.
Applicable to the use of epoxy resin or LIGHTCRIMP connector.
(2) performance advantages
High-performance single-mode and multimode optical fibers comply with all industrial standards.
The 900 μm tightly buffered coat is easy to connect and strip.
Aramid enhances the organization of the anti-tension cables, improving the protection of the optical fiber.
UL/CSA verification meets OFNR and OFNP performance requirements.
Design and testing are performed per Bellcore GR-409-CORE and IEC793-1/794-1 standard.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
The physical structure of a Single-core interconnected optical cable is shown in Figure 4.
　
2. dual-core interconnected Optical Cable
(1) Application Scope
Jumper.
Horizontal cabling directly ends.
Optical fiber to the table.
Communication cabinet wiring panel.
Connect the wall outlet to the workstation.
Applicable to the use of epoxy resin or LIGHTCRIMP connector.
(2) performance and characteristics
Optical fibers are easy to differentiate.
High-performance single-mode and multimode optical fibers comply with all industrial standards.
The 900 μm tightly buffered coat is easy to connect and strip.
Aramid enhances the protection of optical fiber cables.
UL/CSA verification meets OFNR and OFNP performance requirements.
Design and testing are performed per Bellcore GR-409-CORE and IEC793-1/794-1 standard.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
The dual-core physical structure of the interconnected optical cable is shown in Figure 5. The physical structure of the 4-core optical cable is shown in Figure 6. The mechanical properties of interconnected optical cables are shown in table 3.
　
　
3. Distributed Optical Cable
(1) Application Scope
Horizontal cabling of Multi-Point Information ports.
Vertical wiring.
Trunk cabling in the building.
Connection from device to passive jumper.
From the main branch to each floor.
It is applicable to the glue optical fiber connector and LIGHTCRIMP Optical Fiber head.
(2) performance and characteristics
High-performance single-mode and multimode optical fibers comply with all industrial standards.
The 900 μm tightly buffered coat is easy to connect and strip.
Marked according to the EZA standard color code.
UL/CSA verification meets OFNR and OFNP performance requirements.
Design and testing are performed per Bellcore GR-409-CORE and IEC793-1/794-1 standard.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
The protective net can defend against sharp object damage.
Distributed Optical Fiber, multi-unit distributed 12-core optical fiber, and multi-unit distributed type, 24 ~ 72 cores, as shown in physical structure 7.
　
The mechanical properties of distributed optical cables are shown in table 4.
Table 4 mechanical properties of Distributed Optical Cables
4. Distributed Optical Cable
(1) Application Scope
A combination of scattered optical cables.
Multiple optical fiber connections with robust structure.
· Horizontal optical fiber to multi-site egress, simple and direct connection. · Suitable for epoxy optical fiber connector and LIGHTCRIMP Optical Fiber head for direct connection.
(2) performance and characteristics
High-performance single-mode and multimode optical fibers comply with all industrial standards.
The 900 μm tightly buffered coat is easy to connect and strip.
2. 4mm independent optical fiber auxiliary unit, which can be connected with a connection head.
UL/CSA verification meets OFNR and OFNP performance requirements.
Design and testing are performed per Bellcore GR-409-CORE and IEC793-1/794-1 standard.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
The cabling mode is highly flexible.
Aramid enhances the protection of optical fiber cables.
The distributed optical fiber cables are 4-core, 6-core, 8-core, and 12-core. Its physical structure is shown in 8, and its mechanical performance is shown in table 5.
　
5. Outdoor Optical Cable 4 ~ 12-core rack mounting and full Insulation
(1) Application Scope
The connection between buildings in the Park area.
Long-distance network.
Main Line System.
Local Loop and branch network.
Environments with severe humidity and large temperature changes.
Overhead connections (used together with suspension cables), underground pipelines or directly buried or suspended cables/service cables.
(2) performance and characteristics
High-performance single-mode and multimode optical fibers comply with all industrial standards.
The 900 μm tightly buffered coat is easy to connect and strip.
Optical fiber with independent TIA color encoding in the casing.
The lightweight single-channel structure saves space in the tube, and water gel is injected into the tube to prevent water leakage.
Both design and testing are based on the Bellcore GR-20-CORE standards.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
Aramid enhances the protection of optical fiber cables.
Polyethylene outerwear protects ultraviolet rays or harsh outdoor environments.
The low-friction outer leather makes it easy to pass through the pipe, fully insulated or armored structure, and the strip and strip rope makes it easier to strip the outer surface.
The outdoor optical fiber cables are 4-core, 6-core, 8-core, and 12-core, which are both armored and fully insulated. The physical structure is shown in table 6.
　
6. 24 ~ outdoor Optical Cable ~ 144-core armor type and full Insulation Type
(1) Application Scope
The connection between buildings in the Park area.
Long-distance network.
Main Line System.
Local Loop and branch network.
Environments with severe humidity and large temperature changes.
Overhead connections (used with cables), underground pipelines, or directly buried cables.
(2) performance and characteristics
High-performance single-mode and multimode optical fibers comply with all industrial standards.
The insulation structure can avoid lightning strikes.
Optical fiber with independent TIA color encoding in the casing.
The lightweight single-channel structure saves space in the tube, and the waterproof gel is injected into the tube to prevent water infiltration. The injection core is completely wrapped by the polyester tape.
Both design and testing are based on the Bellcore GR-20-CORE standards.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
Aramid is used to enhance the organizational performance and improve the protection of optical fibers.
The polyethylene coat is protected by ultraviolet rays or harsh outdoor environments.
The low-friction outer leather makes it easy to pass through the pipe, fully insulated or armored structure, and the strip and strip rope makes it easier to strip the outer surface.
Outdoor cable 24 ~ 144-core optical fiber cables are fully insulated and armored. The specifications include 24, 36, 48, 60, 72, 96, and 144 cores. The physical structure is shown in 10, the mechanical properties are shown in table 7.
　
7. Single-tube fully insulated indoor/outdoor Optical Cable
(1) Application Scope
Cables can be extended from outdoor devices to indoor devices without any interconnection equipment, and are flame retardant.
Interconnection between buildings in the Park area.
Local line and branch network.
Environments with severe humidity and great temperature changes.
Overhead connections (used together with cables ).
Underground pipelines or direct burial.
· Suspension Cable/service cable.
(2) performance and characteristics
High-performance single-mode and multimode optical fibers comply with all industrial standards.
LSZH is designed to meet the low toxicity and smoke-free requirements.
Optical fiber with independent TIA color encoding in the casing.
The lightweight single-channel structure saves space in the tube, and the waterproof gel is injected into the tube to prevent water infiltration. The injection core is completely wrapped by the polyester tape.
Both design and testing are based on the Bellcore GR-20-CORE standards.
The extension level 62.5/125 complies with the ISO/IEC 11801: 1995 standard.
Aramid is used to enhance the protection of optical fiber cables.
The polyethylene coat is protected by ultraviolet rays or harsh outdoor environments.
The low-friction outer leather makes it easy to pass through the pipe, fully insulated or armored structure, and the strip and strip rope makes it easier to strip the outer surface.
The indoor/outdoor optical cables are 4-core, 6-core, 8-core, 12-core, 24-core, and 32-core. The physical structure is shown in table 8.

During integrated cabling, appropriate optical cable products should be selected based on actual application conditions and the application scope and mechanical performance indicators of optical cables.