Viavi 8100 V2 Series User Manual page 363

Here is a test setup for in-band OSNR testing.
Figure 167 Test setup for In-band OSNR testing
Example:
• OSNR measured with OSCA-710 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)
per EDFA
• Locate and exchange optical amplifier
Chapter 9 OSCA-710 Optical Spectrum Measurement
OSCA-710 OSCA-710
User Manual
OSCA-710
78000010220 Rev. 024
Testing ROADM networks
OSCA-710 OSCA-710
327