Wavelength-division-multiplexed Millimeter-waveband radio-on-fiber system using a supercontinuum light source

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.

I. Introduction

For future millimeter-waveband (mm-waveband) radio-on-fiber (RoF) systems, the wavelength-division-multiplexing (WDM) technique is important to support a huge number of base stations (BSs) connected to a central station (CS) [1]–[3]. It is very attractive to meet increasing demands of wide service coverage of wireless access areas, large capacity in one fiber-optic channel, ease of maintenance, low power consumption, as well as system cost reduction. However, in most previously reported WDM RoF systems, an individual light source is required for each WDM link [4]–[6]. A huge number of light sources have to be accommodated in a CS, resulting in a high-cost and high-maintenance system. Although a mode-locked laser diode (MLLD) is an option for the multiwavelength light source, we have shown that only a few modes were practically available for the data transmission in the WDM RoF system [9], [10]. A recent work modified the wavelength bandwidth for mm-wave signal generation by using a hybrid MLLD [11], but still the available channel number is limited.