Applying a forward bias to a photodiode to shift output
Image from
https://tallerelectronica.com/fotodiodo/
We can start with characteristic of a photodiode,
in the first circuit the voltage accross the photodiode is 0V,
so the working points in the graph are on the y axis (current),
increasing the light will increase the amount of current almost linearly.
If you give a positive voltage on the cathode of the photodiode you are moving to the left on the graph, so it should not have to be a big problem until you reach the reverse voltage of the diode.
If you give a positive voltage on the anode you will turn on the diode (as a regular diode) but I guess this is not the case.