Radio-over-fiber (RoF) links based on reflective electro-absorption modulator (REAM)

There are two types of optical signal modulation in optical communication systems: the direct modulation of the laser diode (LD) radiation and the indirect modulation by using an external modulator. External electro-absorption modulators (EAMs) attracted a great attention in high-speed applications due to low cost, possibility of integration with LDs, low voltage, low power consumption, polarization insensitivity, low chirp, and higher speed operation. Recently, reflective electro-absorption modulators (REAMs) have been proposed for radio-over fiber (RoF) applications. REAM devices have a large available bandwidth, allow fixed and mobile access convergence, and need not lasers in a remote access unit (RAU). In this work, we investigated experimentally the REAM operation in a RAU of a RoF link in the detection and modulation regimes. The measured REAM characteristics and spectra of the detected radio frequency (RF) signals are presented.