Optical Modulation Amplitude (OMA) is the difference between the maximum and minimum optical power levels in a modulated optical signal. It serves as a critical metric for evaluating the depth of modulation, reflecting the extent to which the optical signal's intensity fluctuates. Optical modulation amplitude (OMA): an indicator in an optical signal test. It is given by Average optical power (Pavg): the average receive optical power level, that is, the. In fiber-optic communication, designers and system engineers confront many performance metrics—optical power, extinction ratio, receiver sensitivity, jitter, etc. 23 dB à decrease powers by 2. This measurement can also be made on NRZ waveforms.