Multifunctional fiber-optic microwave links based on remote heterodyne detection

Abstract

Abstract-The multifunctionality of microwave links based on remote heterodyne detection (RHD) of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection (DD) in conjunction with optical intensity modulation is used to implement fiber-optic microwave links. The resulting links are inherently transparent. As opposed to DD links, RHD links can perform radio-system functionalities such as modulation and frequency conversion in addition to transparency. All of these three functionalities are presented and experimentally demonstrated with an RHD link based on a dual-frequency laser transmitter with two offset phase-locked semiconductor lasers. In the modulating link, a 1-Gb/s baseband signal is QPSK modulated onto a 9-GHz RF carrier. The frequency converting link demonstrates up-conversion of a 100-Mb/s PSK signal from a 2-GHz carrier to a 9-GHz carrier with penalty-free transmission over 25 km of optical fiber. Finally, the transparent link transmits a standard FM video 7.6-GHz radio-link signal over 25 km of optical fiber without measurable distortion.

Analyses of numerical and experimental results for optical signal generation using heterodyne scheme

“…It is found that the center of the stable-locking range is shifted toward the lower frequency from the SL lasing frequency as the injection ratio increases. Similar dependence of the stablelocking range on the injection ratio has been shown from the analysis based on Lang's equations [8].…”

“…In order to investigate the effect of the presence of the multiple ML sidebands on the SL spectral characteristics, we have adopted Lang's equations based on the complex electrical field [8]. Then, we have extended those equations representing the laser diode (LD) under multiple lights as follows.…”

60GHz delivery over SMF and MMF for in-door applications

“…Due to its resistance to handling damage, large core graded index polymethylmethacrylate (PMMA) plastic optical fiber (GI-POF) is a preferred choice for in-home networking [3]. This paper demonstrates for the first time, using remote heterodyning technique (RHD) [4], to deliver 5 Gbit/s data over a combination of SMF and MMF-POF cables. The combination of SMF and MMF utilization for mm-wave transmission is highly favorable but yet challenging due to the high bandwidth impairments induced by the MMF-POF material.…”

Simulative investigation the impact of optical amplification techniques on single- and dual-electrode MZM and direct modulator's in single-tone RoF system

“…Several techniques for distributing and generating microwave signals via optical fiber exist. The techniques may be classified into two main categories namely Intensity ModulationDirect Detection (IM-DD) and Remote Heterodyne Detection (RHD) techniques [3]. In such systems, it is desirable to achieve better receiver sensitivities, higher dynamic ranges, and lower nonlinear distortions.…”