1. Introduction to fiber optic patch cords
Optical fiber jumpers (also known as optical fiber connectors) refer to the connector plugs installed on both ends of the optical cable to realize the active connection of the optical path; the plugs on one end are called pigtails.
Fiber patch cords (Optical Fiber Patch Cord/Cable) are similar to coaxial cables, but without a mesh shield. At the center is the glass core where light travels.
In a multimode fiber, the diameter of the core is 50 μm to 65 μm, which is roughly the thickness of a human hair. The diameter of the single-mode fiber core is 8 μm~10 μm. The core is surrounded by a glass envelope with a lower refractive index than the core to keep the fiber within the core. On the outside is a thin plastic jacket that protects the envelope.
Second, the classification of optical fiber jumpers
Optical fiber jumpers can be divided into common silicon-based optical fiber single-mode and multi-mode jumpers according to different transmission media, and other optical fiber jumpers such as plastics as the transmission medium;
According to the structure of the connector, it can be divided into: FC jumper, SC jumper, ST jumper, LC jumper, MTRJ jumper, MPO jumper, MU jumper, SMA jumper, FDDI jumper, E2000 jumper, DIN4 jumper Jumper, D4 jumper and so on. The more common fiber jumpers can also be divided into FC-FC, FC-SC, FC-LC, FC-ST, SC-SC, SC-ST, etc.
Single-mode fiber (Single-mode Fiber): Generally, the fiber jumper is shown in yellow, and the connector and protective sleeve are in blue; the transmission distance is longer.
Multi-mode fiber (Multi-mode Fiber): Generally, the fiber patch cord is indicated in orange, and some are indicated in gray, and the connector and protective sleeve are in beige or black; the transmission distance is short.
Classification of fiber patch cords
3. Precautions for the use of optical fiber jumpers
The transceiver wavelengths of the optical modules at both ends of the fiber jumper must be the same, that is to say, the two ends of the optical fiber must be optical modules with the same wavelength.
In general, short-wave optical modules use multimode fibers (orange fibers), and long-wave optical modules use single-mode fibers (yellow fibers) to ensure the accuracy of data transmission.
Do not bend and loop the optical fiber excessively during use, which will increase the attenuation of light during transmission.
After using the optical fiber jumper, it is necessary to protect the optical fiber connector with a protective sleeve. Dust and oil will damage the coupling of the optical fiber. If the optical fiber connector is dirty, you can use a cotton swab dipped in alcohol to clean it, otherwise the communication quality will be affected.
1. Before use, the ceramic ferrule and the end face of the fiber jumper must be wiped clean with alcohol and absorbent cotton.
2. The minimum bending radius of the optical fiber is less than 30mm.
3. Protect the ferrule and the end face of the ferrule to prevent bumps and pollution, and put on a dust cap in time after disassembly.
4. Do not look directly at the fiber end face when the laser signal is transmitted.
5. The damaged fiber jumper should be replaced in time in the event of man-made and other force majeure damage.
6. Read the manual carefully before installation, and carry out installation and debugging under the guidance of the engineer of the manufacturer or dealer.
7. If the optical fiber network or system is abnormal, the troubleshooting method can be used to test one by one. When testing or troubleshooting the jumper, you can do the on-off test first. Usually, you can use a visible laser pointer to judge the entire fiber link. Or further use a precision optical fiber insertion loss and return loss instrument to test its various indicators. If the indicators are within the qualified range, the jumper indicates normal, otherwise it is unqualified.
Fourth, the characteristics of optical fiber jumpers
1. Low insertion loss
2. Good repeatability
3. Large return loss
4. Good inter-plug performance
5. Good temperature stability
6. Strong tensile properties
Five, the application of optical fiber jumper
Optical fiber jumper products are widely used in: communication room, fiber-to-the-home, local area network, optical fiber sensor, optical fiber communication system, optical fiber connection transmission equipment, national defense combat readiness, etc. It is suitable for cable television network, telecommunication network, computer optical fiber network and optical test equipment. The subdivision is mainly used in several aspects.
1. Optical fiber communication system
2. Optical fiber access network
3. Optical fiber data transmission
4. Optical fiber CATV
5. Local Area Network (LAN)
6. Test equipment
7. Optical fiber sensor
6. Selection of fiber jumpers
There are three main types of fiber jumpers according to the termination type: ST-ST, SC-SC, ST-SC.
According to the type of fiber, there are mainly two types of single-mode fiber and multi-mode fiber.
The specifications of the jumper length are 0.5m, 1m, 2m, 3m, 5m, 10m and so on.
According to the cable outer sheath material, it can be divided into ordinary type, ordinary flame-retardant type, low-smoke halogen-free type (LZSH), low-smoke halogen-free flame-retardant type, etc.
According to the fire rating of the building and the fire resistance requirements of the materials, corresponding measures should be taken for the integrated wiring system.
When laying cables or optical cables in flammable areas and building shafts, flame-retardant cables and optical cables should be used;
Fire-retardant, low-smoke, low-toxicity cables or optical cables should be used in large public places;
Fire-retardant wiring equipment should be used between adjacent equipment or between the junctions.
Seven, the difference between fiber jumper and fiber pigtail
Fiber patch cords are used to make patch cords from equipment to fiber optic cabling links. There is a thicker protective layer, which is generally used for the connection between the optical transceiver and the terminal box.
Pigtail, also known as pigtail, has only one end with a connector, and the other end is a broken end of a fiber optic cable core. It is connected to other fiber optic cable cores by welding. It often appears in fiber optic terminal boxes. (couplers, jumpers, etc. are also used between them).
Optical fiber connector is a device for detachable (active) connection between optical fiber and optical fiber. It precisely connects the two end faces of optical fiber, so that the light energy output by the transmitting fiber can be coupled to the receiving fiber to the maximum extent. And minimize the impact on the system due to its involvement in the optical link, which is the basic requirement of fiber optic connectors. To a certain extent, fiber optic connectors also affect the reliability and performance of optical transmission systems.
Eight, how to detect whether the fiber jumper is qualified
Use an insertion and return loss tester to first measure whether the jumper is clear with a light-passing pen, and make sure that the optical fiber is not broken. The general carrier-level test indicators: the insertion loss is less than 0.3dB, and the return loss is greater than 45dB.
The performance testing of optical fiber jumpers is divided into:
1. Optical performance testing
Including return loss/insertion loss test, the test instrument can use FibKey 7602 return loss/insertion loss integrated tester.
2. End face geometry test
Parameters tested include curvature radius, vertex offset, fiber height, etc. The test instrument is an interferometer, and many people use NorlandAC/NC3000 or CC6000 for testing. Especially the CC6000 interferometer is used by more and more factories because of its superior cost performance.
3. Optical fiber end face scratch detection
Use a video fiber optic magnifier to observe, such as many factories use FibView FV-400PA for inspection. The instrument gives the clearest images and is extremely easy to operate. Some customers also use the FibKey-5600 variable magnification magnifier for testing. The instrument integrates 400x, 200x, and 80x magnifiers, which can clearly and conveniently observe the fiber end face and the ferrule end face. Of course, you can also use the relevant software to automatically check.
4. Optical fiber tensile test
It is necessary to test the tensile force that the fiber optic connector can withstand.
5. Ambient temperature experiment
It is necessary to test the performance indicators of optical fiber connectors under different ambient temperature conditions.
Nine, common application of common fiber jumper interface
The common interface types of fiber jumpers are FC, SC, ST, PC, APC, and LC. Fiber jumpers with FC connectors are mostly used on patch panels, while fiber jumpers with SC connectors are mostly used on routers and switches. In addition, there are various forms of optical fiber interface types such as MTRJ, MPO, MU, SMA, FDDI, E2000, and D4.
Fiber jumper interface
Optical fiber jumper connectors are a problem that users must consider when purchasing optical fiber jumpers. Understanding the meaning of various optical fiber jumper connectors can help users find the products they want faster.
FC type fiber jumper
The external reinforcement method is a metal sleeve, and the fastening method is a turnbuckle. The FC connector is generally used in telecommunication networks. There is a nut screwed onto the adapter. The advantage is that it is reliable and dust-proof. The disadvantage is that the installation time is slightly longer. Generally used on the ODF side (the most used on the patch panel, and also mostly used for optical transceivers)
SC type fiber patch cord
The connector for connecting the GBIC optical module has a rectangular shell, and the fastening method is a plug-and-pull type, which does not need to be rotated. The SC connector is directly plugged and unplugged, which is very convenient to use, but the disadvantage is that it is easy to fall out (the most used on routers and switches)
ST type fiber patch cord
After the ST head is inserted, it is fixed by a bayonet half-circle and is fixed. (For 10Base-F connections, the connectors are usually ST type.
LC fiber patch cord
A connector for connecting SFP modules, constructed with an easy-to-use modular jack (RJ) latch mechanism. (SFP optical module default LC interface)
MT-RJ type fiber jumper
A square fiber optic connector with integrated transceiver, one dual-fiber transceiver is integrated. MTRJ type fiber optic patch cord consists of two high-precision plastic molded connectors and fiber optic cables. The outer parts of the connector are precision plastic parts, including a push-pull plug-in clamping mechanism. Suitable for indoor applications in telecommunication and data network systems.
