If first peak is 1dBm and second - 40dBm, what will be wavelength measurement accuracy difference for second peak?
The WLM does not have 40dB of dynamic range, so the second peak cannot be measure properly. If the second peak is 20dB below the first peak, the wavelength of the second peak can be measured as accurately as the first peak. This is in case of two peaks. If there are more peaks, the accuracy gets worse. (AQ6151 - WLM Accuracy)
A Michelson interferometer-based optical wavelength meter with high measurement performance and excellent cost performance that meets measurement needs from optical devices to optical transmission equipment.