Combining two DC voltages for laser locking

[PChemory]

I need to combine two DC voltages to scan and lock a laser. The scanning will be 0-100 V and the locking will be performed with a small correcting voltage, +/- 1 V. Both of these will be fed into a PZT driver. My advisor suggested using an opto isolator, however I am not sure how that would work unless there are opto isolators that exist with two LEDs and one detector. Also, I am unsure how that would work with the negative voltages. Any help would be really appreciated, as a chemist I only have a general physics knowledge of electronics.

 

[berkeman]

I need to combine two DC voltages to scan and lock a laser. The scanning will be 0-100 V and the locking will be performed with a small correcting voltage, +/- 1 V. Both of these will be fed into a PZT driver. My advisor suggested using an opto isolator, however I am not sure how that would work unless there are opto isolators that exist with two LEDs and one detector. Also, I am unsure how that would work with the negative voltages. Any help would be really appreciated, as a chemist I only have a general physics knowledge of electronics.

Welcome to the PF.

Can you post more about the setup? What is the source of the 0-100V? What is the source of the +/- 1V? What is the input impedance of the PZT driver?

If your 0-100V source can be offset by driving its negative terminal, that might be the easiest way to do this...Like when you offset the black terminal on the power supply below (don't connect it directly to Earth Ground):

https://images-na.ssl-images-amazon.com/images/I/514hEOQXZAL._SX342_.jpg