I'd like to send two currents along a long twisted pair (well, ~5m, but I want to be very careful about noise in this experiment). The two currents are produced by two photodiodes with equal and opposite bias voltages, with the same incident light, giving equal and opposite currents. At the receiver end, these currents are sensed by a transimpedance amplifier into an ADC.
Sending voltages differentially gives a benefit to common mode noise rejection. Does the same benefit apply to differential sending of currents? I am unsure as to the mechanism by which "pick-up" from EM interference affects the signal. I'm interested in sensing signals up to around 100kHz.