This paper presents the design and measurement of an adaptive 3-tap feed-forward equalizer (FFE) integrated circuit (IC) manufactured in 28-nm digital bulk CMOS technology. The driver consumes only 100 mW from a single 1.5 V supply including the vertical-cavity surface-emitting laser (VCSEL) and excluding the input matching circuitry. The 50 Ω input baluns, necessary only for the measurement, are not power optimized and consume 60 mW. The driver was assembled on a printed circuit board (PCB) with DC connections and bonded to a commercially available 7.5 GHz VCSEL diode. An error-free (BER < 10^-12) optical transmission with a data rate (DR) of 25 Gbit/s was achieved. It is proven that the 3-tap FFE improves the quality of the optical eye diagram at a cost of eye amplitude. When not needed, the circuitry of the FFE can be switched off saving 22.5 mW of power.