An experimental study on a self-oscillating optoelectronic up-converter that uses a heterojunction bipolar transistor

Remote downconversion with wavelength reuse for the radio/fiber uplink connection

“…Downconversion of the uplink data to IF at the BS eliminates the requirement for high-speed external modulators or high-speed laser diodes that might be necessary if other architectures are implemented [4], [6]. The IF modulation also allows the transmission of many RF channels simultaneously using the same light source (using SCM) as well as the transmission of a DSB signal without it being exposed to dispersion-caused fading.…”

“…The need for a light source at the BS is avoided by reusing the optical carrier from the downlink as proposed in [4]- [6]. Nevertheless, because we transmit the uplink and downlink signals using different RF frequency, our method allows the simultaneous transmission of the signals in both directions using the same wavelength and fiber (RF modulated carrier for downlink and IF modulated for uplink).…”

“…There has been a lot of research activity in this area and some of the proposed methods of optical RF generation are direct and external modulation, heterodyning, mode-locking of a laser, and remote upconversion using the phototransistors, etc. [1]- [4].…”

“…In this letter, we propose a simple uplink configuration by reducing the amount of high-speed components at the BS. We achieve this by transmitting an unmodulated RF carrier from the CS to the BS, where it is detected and used to downconvert the uplink data to an intermediate frequency (IF) [it acts as a local oscillator (LO)] [4]. In addition, the need for a light source at the BS is also omitted by reflecting part of the downlink optical carrier and modulating it, using a Mach-Zehnder modulator (MZM), with the IF uplink data.…”

Remote downconversion scheme for uplink configuration in radio/fiber systems

“…There has been a lot of research activity in this area and some of the proposed methods of optical RF generation are direct and external modulation, heterodyning, mode-locking of a laser, remote upconversion using the phototransistors etc. [1][2][3][4].…”