There are two commonly used fiber optic testers. They are optical time domain reflectometer (OTDR) and visual fault locator.
OTDR is the most classic fiber tester, and can provide the most information on testing optical fiber. The OTDR itself is a one-dimensional closed-loop optical radar, measuring the distance from one end of an optical fiber head. Emitting the high intensity, narrow optical pulses into the optical fiber, while the optical probe at high speed record return signal. This instrument gives a visual interpretation of the optical link. OTDR curve reflects the continuation point, the size of the connector and the location of the point of failure, and loss.
OTDR evaluation process has many similarities with optical multimeter. In fact, OTDR can be considered as a very professional test instrument combination: a stable high-speed pulse source and a high-speed optical probe. The selection process of OTDR can be focus on the following attributes.
1). Confirming the operating wavelength, fiber type and connector interface.
2). The expected loss of the connection and the need to scan the range.
3). The spatial resolution.
Most of the visual fault locator is a handheld instrument suitable for multimode and single-mode fiber-optic system. The use of OTDR technology for fiber fault point location, most of the test distance in less than 20 km. Instrument directly to the digital display the distance to the point of failure. : Wide Area Network (WAN), the 20-km range communication systems, fiber-to-roadside (FTTC), single-mode and multi-mode fiber optic cable installation and maintenance, and military systems. Single-mode and multi-mode fiber optic cable system, it is necessary to locate the connector failure, bad splices, visual fault locator is an excellent tool. The visual fault locator simple just a one-button operation, multiple events can be detected up to seven.
Visual fault locator: the performance for fiber loss function of the distance. With OTDR, technicians can see the outline of the entire system, to identify and measure the span of fiber splice points and connected head. Diagnosis meter fiber failure, OTDR is the most classic but also the most expensive instrument. With the ends of the optical power meter and optical multimeter test, OTDR only through the end of the fiber can be measured fiber loss. The position and size of the the OTDR trace line gives the attenuation value of the system, such as: any connectors, splices, optical fiber shaped, or the position of the fiber break its loss size.
OTDR can be used in the following three aspects:
1). In the understanding of the characteristics of the cable (length and attenuation), before being laid.
2). To obtain the signal trajectory line waveform of the period of the optical fiber.
3). Positioning serious point of failure when problem increased and connected worsening .
Visual fault locator is a special version of OTDR. It can automatically find fiber failures without the OTDR complex steps, and its price is also just fraction of OTDR.