A method for producing an optical output in substantially linear relationship with an input electrical AC signal, including the following steps: providing a light-emitting transistor having emitter, base, and collector regions, the light-emitting transistor producing light emission from its base region in response to electrical signals applied with respect to the emitter, base, and collector regions; applying a signal derived from the input signal to the light-emitting transistor; deriving a feedback signal from an electrical operating signal of the light-emitting transistor; applying a predistortion factor to the derived feedback signal to produce a predistorted feedback signal; and combining the predistorted feedback signal with the input signal to produce the signal derived from thr input signal; whereby the light emission comprises an optical output in substantially linear relationship with the input signal.