Measurement Of I-Osnr; Mode - Viavi 8100 V2 Series User Manual

Portable, modular platform designed for the construction, validation and maintenance of optical fiber networks

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Test setup for In-band OSNR testing

OSNR measured with in-band OSA-500R or OSA-500RS at terminal site (1)

provides value of 14dB

Service failed as the OSNR is < 20 dB

How to locate the failure?

Perform the following tests at EDFA monitor access points (2-5):

Check per channel input and output power of EDFA

=> Input power must be in the system specified range

Check power uniformity

=> Equal power levels for all channels at EDFA output

Compare OSNR from EDFA to EDFA

=> OSNR may decrease because of the amplifier noise figure NF (type 3-4 dB)

Locate and exchange optical amplifier

Measurement of I-OSNR

Pre-setting the OSA for an in-band OSNR

measurement in I-OSNR mode

As the out-of-band OSNR measurements might not provide the 'TRUE' OSNR value for

the above listed systems configurations, the in-band OSNR measurement method

based on Viavi's polarization nulling technique must be selected.

Chapter 8 Optical Spectrum Measurement

OSA-500RS OSA-500RS

78000010220 Rev. 024

Measurement of I-OSNR