Testing and Troubleshooting of Fiber Optic Networks

In recent years, as people have higher and higher requirements for broadband speed, because the performance of optical fiber is better than that of copper cable, it is widely used in the backbone construction of broadband projects. At the same time, due to the increasing coverage of optical fibers, the detection of optical fiber faults is becoming more and more important. What methods can be used to eliminate the faults of optical fiber components?

First of all, to eliminate the failure of optical fiber components, it is definitely necessary to pass the test, so what are the test and measurement equipment for optical fiber network? At present, the super six kinds of network cable manufacturer Finite understands that there are mainly three kinds of instruments. They are: optical loss test equipment (also known as optical multimeter or optical power meter), fault locator (fault tracker), and optical fiber identifier.

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1. Optical loss test equipment (combined with an optical multimeter and an optical power meter)

Optical Power Meter: Used to measure absolute optical power or relative loss of optical power through a length of fiber. Optical Multimeter: Used to measure the optical power loss of fiber optic links.

To measure the loss of a fiber optic link, calibrated, steady light is emitted at one end and the output power is read out at the receiving end. These two devices constitute an optical loss tester. When a light source and a power meter are combined into a set of instruments, it is often called an optical loss tester (also called an optical multimeter). When we measure the loss of a link, one person needs to operate the test light source at the transmitting end and another person uses the optical power meter to measure at the receiving end, so that the loss value in one direction can only be obtained.

Usually, we need to measure the loss in both directions (because of directional connection loss or due to the asymmetry of cable transmission loss). At this point, technicians must exchange equipment and take measurements in the other direction. However, what to do when they are separated by dozens of floors or tens of kilometers? Obviously, if these two people each have a light source and an optical power meter, then they can measure on both sides at the same time, and now the advanced optical cable test kits for certification testing can achieve bidirectional dual wavelength testing .

2. Optical fiber fault locator (fault tracker)

Fault locators are mostly hand-held instruments for multimode and singlemode fiber optic systems. Using OTDR (Optical Time Domain Reflectometry) technology, it is used to locate the point of optical fiber fault, and the test distance is mostly within 20 kilometers. The instrument directly digitally displays the distance to the fault point. Ideal for: Wide Area Networks (WANs), 20 km range communication systems, Fiber to the Curb (FTTC), installation and maintenance of singlemode and multimode fiber optic cables, and military systems. A fault locator is an excellent tool for locating faulty connectors and bad splice points in singlemode and multimode fiber optic cable systems. The fault locator is simple to operate and can detect up to 7 multiple events with a single button operation.

This device is based on a laser diode visible light (red light) source. When light is injected into the optical fiber, if the optical fiber is broken, connector failure, excessive bending, poor fusion quality and other similar faults, the light emitted to the optical fiber can be transmitted to the optical fiber. The fault can be located visually. Visual fault locators transmit in continuous wave (CW) or pulsed mode. Typical frequencies are 1Hz or 2Hz, but can also operate in the kHz range. The typical output power is 0dBm (1Mw) or less, the working distance is 2 to 5km, and it supports all common connectors.

3. Optical fiber identifier

It is a very sensitive photodetector. When you bend a fiber, some light radiates out of the core. These lights are detected by fiber identifiers, which allow technicians to identify individual fibers in multi-core cables or patch panels from other fibers. Fiber identifiers can detect the state and direction of light without affecting transmission. To make this work easier, the test signal is usually modulated to 270Hz, 1000Hz or 2000Hz at the transmit end and injected into a specific fiber. Most fiber identifiers are used for single-mode fiber optic cables with operating wavelengths of 1310nm or 1550nm. The best fiber identifiers can use macrobend technology to identify the transmission direction and power in the cable and test the cable online.

To sum up, a project that uses a large number of optical fiber equipment is generally a large-scale project. To complete a measurement of optical loss or troubleshoot optical fiber equipment, a calibrated light source and a standard optical power meter are impossible. Lack of.