Patent ID: 7020395

Claim:
An optical transmission apparatus having an optical performance monitoring function, the apparatus comprising: a light output unit for selecting and outputting light of one of a plurality of wavelengths; a digital information conversion unit for measuring a performance parameter of the output light and converting the measurement result into a digital value, wherein the digital value falls within a normal range when the light output unit is accurately adjusted, and wherein the normal range is a function of the wavelength of the output light; a conversion map for mapping a set of digital values onto a set of monitored values in such a way that every digital value in the normal range is mapped onto a same monitored value regardless of the wavelength of the output light; a conversion map management unit for obtaining, from said conversion map, one of the monitored values that corresponds to a combination of the normal range and the digital value representing the measured performance parameter; and a display control unit for displaying the obtained monitored value.