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We propose to use a supercontinuum (SC) for a low-phase-noise multiwavelength light source in wavelength-division-multiplexing (WDM) millimeter-waveband (mm-waveband) radio-on-fiber (RoF) systems. We demonstrate the generation of low-phase-noise 60-GHz-band RoF signal. We also demonstrate the generation of two-channel WDM 60-GHz-band RoF signals and the transmission of the signals over a 25-km standard single-mode fiber (SMF) using photonic upconversion. The single multiwavelength light source can be shared with a number of users and simplifies the system configuration, which would allow the realization of high-reliability as well as low-cost RoF systems. Finally, the RoF network capacity with a single SC light source is estimated to be over 10 000 channels when the spectrum of the SC light source is fully utilized. [ABSTRACT FROM PUBLISHER]

Simultaneous modulation of 2.5-Gb/s baseband, microwave-band, and 59.6-GHz 155.52-Mb/s differential phase-shift keying signals on a single wavelength, using a single 60-GHz-band electroabsorption modulator (EAM), and fiber-optic transmission over a 40-km-long dispersion-shifted fiber (DSF) was experimentally demonstrated. The optimum operating conditions for three-band modulation and transmission were theoretically investigated. Degradation due to the nonlinearity of the EAM for the millimeter-wave signal is discussed theoretically. The fading problem due to the fiber dispersion of the standard single-mode fiber and the DSF was also investigated. [ABSTRACT FROM PUBLISHER]

The frequency-interleaved dense- wavelength-division-multiplexing (DWDM) millimeter-wave (mm-wave) radio-on-fiber is an indispensable technique to improve the optical spectrum efficiency. We propose possible configurations of multiplexing and demultiplexing (DEMUX) schemes using an arrayed-waveguide grating (AWG) with two input and N output waveguides (N: total channel number). In this paper, we focus on the DEMUX scheme and experimentally demonstrate the DEMUX scheme using a commercially available AWG. In the experiment, 25-GHz-separated two-channel optical double sideband signals modulated by a 60-GHz millimeter-wave carrying a 156-Mb/s data are optically multiplexed by the frequency interleaving. The power penalty after DEMUX, which was due to interchannel interference, was less than 0.5 dB. We also made a transmission experiment over 25-km standard single-mode fiber (SMF). No noticeable power penalty in the received data due to chromatic dispersion of the transmission fiber was observed. This is because only the carrier and a sideband are detected in the proposed DEMUX scheme. [ABSTRACT FROM PUBLISHER]

We study the optical filtering technique for dense wavelength division multiplexing (DWDM) channel allocation of millimeter-wave fiber-radio signals in the optical double-sideband (DSB) format. First, we investigate both theoretically and experimentally the dispersion effect of fiber Bragg grating (FBG) used as the filter on DWDM millimeter-wave optical signal transmissions. This result suggests that the dispersion effect has to be considered in the DWDM channel allocation for millimeter-wave fiber-radio access systems. Next, we propose a DWDM allocation for millimeter-wave fiber-radio systems, which adopts the optical single-sideband (SSB) filtering technique at the receiver side by using a square response of FBG filter. It can realize the minimum WDM channel interval for optical DSB signals, while it enables the optical frequency interleave between the neighboring channels without any serious signal degradation due to the interchannel interference. Then, we experimentally demonstrate the error-free DWDM transmission of two 60-GHz-band, 155.52-Mb/s differential phase-shift keying (DPSK) fiber-radio signals over 25-km-long single-mode fiber (SMF) with the minimum channel interval of 83.6 GHz (=0.68 nm) by using the test-square response FBGs. Finally, we show that based upon the experimental results, in the micro- or pico-cellular DWDM broad-band millimeter-wave fiber-radio access network 1000 antenna base stations (BSs) under the coverage of the single central office (CO) would be feasible by sectorizing the zone. [ABSTRACT FROM PUBLISHER]

In this paper, a fiber-optic millimeter-wave (mm-wave) downlink system using 60 GHz-band external modulation is investigated. We prepare the fiber-optic 60 GHz-band mm-wave downlink testbed. It consists of an optical modulation section with a mm-wave signal generator, an optical single sideband (SSB) filter, a standard single-mode fiber (SMF), an optical detection section with a 60 GHz-band radio transmitter and a 60 GHz-band radio receiver. To modulate the laser output with 60 GHz-band mm-wave signals directly, a specially designed electro-absorption modulator with high-efficiency at around 60 GHz is used. The use of this modulator makes the simpler system configuration possible. Using the downlink testbed, the 5 m-long free-space propagation of subcarrier multiplexed 156 Mb/s-DPSK 60 GHz-band mm-wave signals recovered by optical direct detection is successfully demonstrated. The transmission of the mm-wave signals over 85 km-long standard SMF is also successfully demonstrated, using an optical SSB filtering technique to overcome the fiber dispersion. The BER of 10-9 is achievable at the optical received power of -7.0 dBm [ABSTRACT FROM PUBLISHER]

We newly propose a photonic downconversion technique with optical frequency shift to detect millimeter-wave-band (mm-wave-band) radio-on-fiber (ROF) signals. In the proposed technique, the carrier and first-order sideband components of mm-wave-band ROF signal are differentially shifted closer to each other in the optical domain on the receiver side. The closely aligned optical components are filtered out and photodetected to generate a desired intermediate-frequency signal in the microwave band. We describe the theoretical basis for our proposal and the experimental transmission of a 60-GHz band 155-Mb/s differential phase-shift keying ROF signal over a 25-km-long standard single-mode fiber. [ABSTRACT FROM PUBLISHER]

A full-duplex radio-on-fiber system using a newly developed 60-GHz-band optical transceiver is investigated. We fabricated a 60-GHz-band two-radio-frequency (RF)-port electroabsorption transceiver (EAT) module, which is the first developed 60-GHz-band optical transceiver in the world. The EAT module has individual RF input and output ports, each with impedance-matching circuits that enhance modulation and detection efficiencies near 60 GHz. A radio-on-fiber testbed adopting the EAT has an advantage that a base station becomes the simplest configuration, which basically consists of only the 60-GHz-band EAT. Using the radio-on-fiber testbed, the simultaneous transmission of 59.6-GHz (downlink) and 60.0-GHz (uplink) signals with data of 156 Mb/s is experimentally demonstrated [ABSTRACT FROM PUBLISHER]

By optimizing the driving conditions of a highspeed electroabsorption modulator, we achieved a significant fiber-length extension and dispersion penalty reduction in a 60-GHz millimeter-wave indoor fiber-optic transmission system. In particular, we demonstrate simultaneous transmission of two 156-Mb/s data channels in the 60-GHz band over 1409-m standard single-mode fiber without employing an additional dispersion compensation technique [ABSTRACT FROM PUBLISHER]