What is working principle of OTDR?

What is working principle of OTDR?

The operating principle of an OTDR is similar to that of radar. OTDR performs timed measurements of reflected light. When a signal is transmitted through an optical fiber cable then during transmission some part of the signal gets reflected.

How do you perform an OTDR test?

Test Procedure

  1. Turn on OTDR and allow time to warm-up.
  2. Clean all connectors and mating adapters.
  3. Attach launch cable to OTDR. Attach receive cable (if used) to far end of cable.
  4. Set up test parameters on OTDR.
  5. Attach cable to test to end of launch cable. Attach receive cable (if used) to far end of cable.
  6. Acquire trace.

What is the application of OTDR?

The Optical Time Domain Reflectometer (OTDR) is useful for testing the integrity of fiber optic cables. It can verify splice loss, measure length and find faults. The OTDR is also commonly used to create a “picture” of fiber optic cable when it is newly installed.

What is OTDR device?

An Optical Time Domain Reflectometer (OTDR) is a device that tests the integrity of a fiber cable and is used for the building, certifying, maintaining, and troubleshooting fiber optic systems.

What is pulse in OTDR?

In an OTDR, the pulse carries the energy required to create the backreflection for link characterization. The shorter the pulse, the less energy it carries and the shorter the distance it travels due to the loss along the link (i.e., attenuation, connectors, splices, etc.).

What is OTDR testing?

How do you read an OTDR test?

How to Read Your Trace. OTDR displays will show a Y and X axis. The X axis measures distance, and the Y axis measures attenuation and reflection in dB. Before running your trace, select the appropriate fiber network length, pulse width and acquisition time.

Which diode is used in OTDR?

60mw-80mw 1310nm Pulse Laser Diode. It is widely used in OTDR system.

What is wavelength in OTDR testing?

OTDR test pulse width wavelength: Normally, it’s 850 nm on multimode fiber optic cable and 1,310 nm on single-mode—the shorter wavelength has more back-scatter, so the trace will be less noisy.

What is the difference between a TDR and an OTDR?

Essentially an optical time domain reflectometer, OTDR is the equivalent of an electronic TDR, but for optical fibres. It then receives and analyses the light that is scattered by Rayleigh backscatter or reflected back from points along the fibre.

What is reflectance in OTDR?

Reflectance (which has also been called “back reflection” or optical return loss) of a connection is the amount of light that is reflected back up the fiber toward the source by light reflections off the interface of the polished end surface of the mated connectors and air.

What is the preferred wavelength setting for the OTDR?

Generally speaking, 1625 nm is the preferred wavelength for monitoring legacy 1310/1550-nm systems, largely due to laser cost. The 1650-nm wavelength is recommended for CWDM, DWDM, XGS-PON, and TWDM-PON systems where the traffic wavelengths extend into the L-Band.

What is the working principle of OTDR?

Working Principle and Characteristics of OTDR. The Optical Time Domain Reflectometer (OTDR) is an essential tool used to test the integrity of fiber optic cables, which can be applied to evaluate the length of fiber cables, measure transmission and connection attenuation and to detect the fault location of fiber links as well.

What does the distance range setting on an OTDR do?

The distance range setting on an OTDR controls the display range for the amount of cable to be presented on the screen. It also defines the rate of pulse emission, since each pulse must be returned to the detector before the next pulse is sent out. Setting this parameter appropriately requires accurate documentation of the optical fiber link.

How does the OTDR measure loss in optical fiber?

However, the OTDR uses a unique optical phenomena “backscattered light” to make measurements along with reflected light from connectors or cleaved fiber ends, thus to measure loss indirectly.

What is the Dead Zone in OTDR?

As the OTDR is working, time is converted into distance, therefore, more reflections lead to more time for the detector to recover, thus resulting a longer dead zone. Dead zone limits the operation of OTDR to a large extent, making it unable to locate and resolve faults.