What determines the Saturation Power in the receivers (detectors with amplifiers)?
The value given for the saturation power is determined by the maximum photocurrent that can go into the RF amplifier before saturation. It is also stated as the maximum responsivity. Therefore, if you’re using the receivers at a wavelength other than at maximum responsivity you will be able to input a higher optical power as proportional to the decrease in responsivity. For example, with the Model 1617 high-speed balanced receiver, the saturation power is 1 mW at 1600 nm. At 950 nm, the responsivity is 0.5 A/W versus 1.0 A/W at 1600 nm. Therefore the saturation power is 2 mW. Also, note that with these balanced receivers, since the saturation power is due to the current into the RF amplifier, you are limited by the difference photocurrent. Thus, you can put more than the saturation power on each photodetector as long as the difference between the two powers is less than the saturation power stated in the specification table.
