The typical expected optical insertion loss (IL) from an AC99x series (i.e. AC990, AC990P, AC991P) integrating sphere is as follows...
MM source (850nm and 1300nm):Between 27.7dB and 34.1dB depending on wavelength SM source (1310nm, 1490nm, 1550nm, 1625nm): Between 29.7dB and 37.8dB depending on wavelength
SM source (1310nm, 1490nm, 1550nm, 1625nm): Between 29.7dB and 37.8dB depending on wavelength