The Agilent 81625A optical heads are specially designed for low PDL, low spectral ripple, and high return loss and are used for optical component tests.
It works with both the 81618A and the 81619A, single and dual port respectively, interface modules.
This unit has has the following specifications:
Optical Wavelength Range: 850 - 1650 nm
Optical Power Range: +20 dBm to -80 dBm
Sensor Element: InGaAs
It is used in the lightwave mainframe models 8163A/B, 8164A/B, and 8166A /B