Total radiant flux is the spatially integrated total light output from a light source. Lasers are monochromatic light sources with optical powers at finite wavelengths, so their optical power is characterized as the power at a specific wavelength; 5 mW at 1064 nm as an example.
Laser diodes are also monochromatic light sources and are commonly tested in diode form, diode bar, or in a module with and without the module fiber. Laser diodes are used in communication applications often in remote hard to get to places such as sea beds or earth orbiting satellites, therefore laser diodes are typically tested for their optical power, peak wavelength and life.
The most common and convenient method for measuring the total radiant power and peak wavelength simultaneously is using an integrating sphere laser power meter. Integrating sphere laser power meters are calibrated to measure optical power and when combined with a high resolution spectrometer, OSA or wavemeter the peak wavelength can be monitored in parallel with the power monitor for life test applications.
Typical quantities of interest are total radiant flux, peak wavelength and rated life.