Performance Assessment of Radio Links Using Millimeter-Wave Over Fiber Technology With Carrier Suppression Through Modulation Index Enhancement
ABSTRACT We have proposed and experimentally demonstrated a new radio-over-fiber system technique generating optical millimeter-waves with central carriers suppressed by simply tuning the modulation index of an optical phase modulator without requiring any complicated bias control circuits or narrowband optical filters. Error-free transmission of the generated 40-GHz optical mm-wave with 2.5-Gb/s data over 10-km single mode fiber (SMF-28) and 3-m air distance was achieved. The experimental results were analyzed and compared with the traditional method that requires a specific carrier suppression optical filter. The power penalty caused by the crosstalk between wavelength division multiplexed (WDM) channels was experimentally measured and studied and was about 4 dB at a bit error rate (BER) of 10-9. The filter bandwidth requirement, achievable carrier suppression ratio, and harmonics fluctuation due to fiber dispersion were also theoretically analyzed.
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ABSTRACT: A full-duplex lightwave transport system employing phase-modulated radio-over-fiber (RoF) and intensity-remodulated CATV signals in two-way transmission is proposed and experimentally demonstrated. The transmission performances of RoF and CATV signals are investigated in bidirectional way, with the assistance of only one optical sideband and optical single sideband (SSB) schemes at the receiving sites. The experimental results show that the limitation on the optical modulation index (OMI) of the downlink RoF signal can be relaxed due to the constant intensity of phase modulation scheme. Impressive transmission performances of bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) were obtained over two 20-km single-mode fiber (SMF) links. This proposed system reveals an outstanding one with economy and convenience to be installed.Optics Express 07/2011; 19(15):14000-7. DOI:10.1364/OE.19.014000 · 3.53 Impact Factor
Conference Paper: Impact of Crosstalk on Indoor WDM Optical Wireless Communication Systems[Show abstract] [Hide abstract]
ABSTRACT: In this paper, we investigate the impact of optical crosstalk on our recently proposed indoor gigabit optical wireless (OW) communication system incorporating wavelength division multiplexing (WDM). A theoretical model that allows this impact to be assessed has been proposed. The analytical results are validated via experiments. We show that the power penalty due to crosstalk in our proposed indoor WDM OW system is lower compared to that in the conventional optical fiber communication systems. In addition, it is found that the power penalty due to crosstalk is lower for the higher speed system since the receiver preamplifier-induced noise dominates the noise process. Finally, the maximum error-free beam footprint for different levels of optical crosstalk has been investigated. The results show that, for the 10- and 12.5-Gb/s systems, the maximum error-free beam footprint is only reduced by similar to 5 cm, even with comparatively strong crosstalk.OptoeElectronics and Communications Conference (OECC), 2011 16th; 04/2012
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ABSTRACT: In this paper we experimentally investigate a gigabit indoor optical wireless communication system with single channel imaging receiver. It is shown that the use of single channel imaging receiver rejects most of the background light. This single channel imaging receiver is composed of an imaging lens and a small photo-sensitive area photodiode attached on a 2-axis actuator. The actuator and photodiode are placed on the focal plane of the lens to search for the focused light spot. The actuator is voice-coil based and it is low cost and commercially available. With this single channel imaging receiver, bit rate as high as 12.5 Gbps has been successfully demonstrated and the maximum error-free (BER<10⁻⁹) beam footprint is even larger than 1 m. Compared with our previous experimental results with a single wide field-of-view non-imaging receiver, an improvement in error-free beam footprint of >20% has been achieved. When this system is integrated with our recently proposed optical wireless based indoor localization system, both high speed wireless communication and mobility can be provided to users over the entire room. Furthermore, theoretical analysis has been carried out and the simulation results agree well with the experiments. In addition, since the rough location information of the user is available in our proposed system, instead of searching for the focused light spot over a large area on the focal plane of the lens, only a small possible area needs to be scanned. By further pre-setting a proper comparison threshold when searching for the focused light spot, the time needed for searching can be further reduced.Optics Express 04/2012; 20(8):8442-56. DOI:10.1364/OE.20.008442 · 3.53 Impact Factor