Thank you very much for the answers.
Andy Resnick you get the solution to my problem, i didn't thought about a linear relation between the accuracy and the input level but it seems to be the right answer :wink::wink:
Ok, my OSA is MS9710C from Anritsu, you can find the datasheet here (appendix A).
In any case the minimum detectable power should be -65 dBm as i wrote above (for the sake of completeness i have to say that it changes accordingly to the wavelength range in which you are working, but we can...
Hey!
I've a simple (and maybe stupid) question about the accuracy of an OSA. The datasheet report a level accuracy of 0.4 dB but this seems quite strange to me. Indeed level measurements are done in dBm thus, as long as dB measures a relative power, I assume that even the 0.4 dB are referred to...