An intensity-modulation direct-detection radio-over-fiber link with a tunable transfer function

► An intensity-modulation direct-detection (IMDD) radio-over-fiber link with a tunable transfer function is presented. ► It utilizes a bias drift free intensity modulator based on a Sagnac fiber loop interferometer containing an optical phase modulator. ► By adjusting the polarization controller in the interferometer, the transfer function of the whole system can be tuned. ► Experimental results show that the transfer function can be tuned over a full 180o range.