Reduction of optical beat interference in SCM/WDMA networks using pseudorandom phase modulation

Optical-Beat-Induced Multi-User-Interference Reduction in Single Wavelength OFDMA PON Upstream Multiple Access Systems With Self-Homodyne Coherent Detection

“…In addition, this technique cannot provide multiple access operations on a single nominal wavelength optical carrier, leading to a scalability limitation with WDM. Another proposed technique uses the spectral broadening effect of the optical carrier to avoid OBI noise [6], [9]. A simple and effective spectral broadening technique that modulates the RF clipping tone to the laser has been proposed for SCM-PON and OFDMA PON [6].…”

“…The OBI problem, a main cause of MUI, has been a major obstacle in implementing frequency division multiplexing based PONs such as subcarrier multiplexing passive optical networks (SCM-PONs) and OFDMA PONs [6]- [10]. Our group proposed a solution to this OBI problem that uses an out-of-bandwidth RF clipping tone without polarization states difference between the upstream multiple access signals [9].…”

Multiple Access Techniques for Fiber-Optic Networks

“…Another proposal to reduce OBI consists of polarization randomization of the interfering stream as suggested in [122]. This is achieved by phase modulating the emitted optical field with electro-optic modulators driven by different independent pseudorandom bias voltages.…”

Performance limitations of a subcarrier multiplexed optical fiber link impaired by optical bit interference and intensity noise

“…At the output o the PD, we would expect M terms representing the field intensities, plus M (M-1) cross term, If the spectral content of any one of these cross terms falls within the passband of the bandpass filter (BPF) in the intended user channel, it will cause interference. OBI causes represent a serious limitation on the transmission capacity [4].…”

“…The performance of an optical link with RF Subcarrier multiplexing is limited by the Phase modulation to intensity modulation (PM-IM) conversion due to MachZehnder interferometers used in optical modulator [3]. Further, during the photodetection process there is generation of optical beat interference (OBI), which greatly limits the number of subcarrier that can be multiplexed [4]. In this paper, an analytical approach is presented to evaluate the combined interference of PM-AM conversion and the impact of OBI on the bit error rate (BER) performance of a subcarrier multiplexed optical communication system.…”