What are the 4 parameters for an OTDR?

What are the 4 parameters for an OTDR?

OTDR Parameters

  • Pulse Width. Setting the adjustable pulse width determines the duration of the pulse being emitted into the fiber link.
  • Dead Zones.
  • Distance Range.
  • Averaging Time.

How will you differentiate between a bend & A splice with an OTDR?

The bending looks almost the same as splice, but with one small difference. Splice will produce approximately the same attenuation at both wavelengths. In the case of the fiber bending, the measurement at 1310 nm will not show it at all, or make it poorly visible, and at 1550 nm will produce several decibels!

How does OTDR work PDF?

The OTDR works like RADAR, sending a high power laser light pulse down the fiber and looking for return signals from backscattered light in the fiber itself or reflected light from connector or splice interfaces.

What is reflect dB in OTDR?

Reflectance is defined by the amount of light reflected compared to the power of the light being transmitted down the fiber. Thus a 1% reflectance is -20 dB, which is about what you get from a flat polished air gap connection, and 1 part per million would be -60 dB, typical of an APC connector.

How far maximum km can test with OTDR?

Consequently, a single-mode OTDR with a 35 dB dynamic range has a usable dy- namic range of approximately 30 dB. Assuming typical single-mode fiber attenuation of 0.20 dB/km at 1550 nm, and splices every 2 km (loss of 0.1 dB per splice), such OTDR will be able to accurately certify distances of up to 120 km.

What is span loss in OTDR?

Span loss (PS) = (Fiber attenuation * km) + (Splice attenuation * Number of splices) + (Connector attenuation * Number of connectors) + (In-line device losses) + (Nonlinear losses) + (Safety margin)

What is pulse width in OTDR?

What is Pulse Width? OTDR pulse width determines length of fiber that can be measured before OTDR traces become noise. Larger pulse width provides larger dynamic range. Narrow pulse width provides reduced dynamic range.

What is good dBm for fiber?

Fiber optic sources may vary from -20dBm to +20dBm and receiver power may go as low as -40dBm. That’s not hard to remember. Positive dBm means power greater than 1mw and negative means less than 1mw. A good laser source for a singlemode link will have a power output of ~ +3 to +6 dBm – 2-4mw – coupled into the fiber.

What is an acceptable dB loss on fiber?

For singlemode fiber, the loss is about 0.5 dB per km for 1310 nm sources, 0.4 dB per km for 1550 nm. (1.0 dB/km for premises/0.5 dB/km at either wavelength for outside plant max per EIA/TIA 568)This roughly translates into a loss of 0.1 dB per 600 (200m) feet for 1310 nm, 0.1 dB per 750 feet (250m) for 1300 nm.

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