You still have to consider conduit fill ratios (though fiber usually does not take up much room). But more importantly, you have to make sure the conduit termin

You still have to consider conduit fill ratios (though fiber usually does not take up much room). But more importantly, you have to make sure the conduit terminates on both ends in some way that makes it easy for you to separate out the fiber and power wires accordingly. If the conduit goes from electrical panel to electrical panel it really wouldn't be ideal to pull the fiber through.