Fiber architecture solutions for providing wireless network coverage by radio-over fiber feeding in buildings
are discussed. The focus is on very high wireless data rate applications (>>100 Mb/s) with short wireless
distances (typ. <10m). Up to 20 Gb/s signal transmission at 60 GHz is demonstrated.
We propose a method of optical data storage that exploits the small dimensions of metallic nano-particles
and/or nano-structures to achieve high storage densities. The resonant behavior of these particles (both individual and in
small clusters) in the presence of ultraviolet, visible, and near-infrared light may be used to retrieve pre-recorded
information by far-field spectroscopic optical detection. In plasmonic data storage, a femtosecond laser pulse is focused
to a diffraction-limited spot over a small region of an optical disk containing metallic nano-structures. The digital
information stored in each bit-cell modifies the spectrum of the femtosecond light pulse, which is subsequently detected
in transmission (or reflection) using an optical spectrum analyzer. We present theoretical as well as preliminary
experimental results that confirm the potential of plasmonic nano-structures for high-density optical storage applications.
InP-based vertical cavity surface emitting lasers (VCSELs) with AlGaInAs QWs and AlGaInAs/InP DBR have been
demonstrated. Over 3 mW and ~1 mW powers at both 1.3 μm and 1.55 μm have been achieved at 20 °C and 85 °C,
respectively. Tests for various applications have been performed with our 1.3 and 1.55 μm VCSELs. Error free
transmission over 10 km under 10 Gbit/s, 85°C has been demonstrated with both 1.3 and 1.55 μm VCSELs. The effect of
electrical dispersion compensation (EDC) with 1.55 μm VCSELs has been confirmed for transmission of medium range
data transmission. Radio signal transmission with low error vector magnitude by 1.3 μm VCSELs has been achieved at 2.4
and 5 GHz-band radio frequency.
Fiber-radio systems based on directly modulated high-speed VCSELs are investigated at both 850 nm and 1300 nm.
Multimode fiber for short reach applications as well as single-mode fiber to bridge longer distances have been
demonstrated to show high performance. Laser noise and linearity characterization as well as system design to achieve
high spur-free dynamic range of >95 dB•Hz2/3 are discussed. A comparative study of radio signal transport solutions based
on fiber or coaxial cable is presented and the long transmission distances achievable over multimode fiber links presented.
A picocellular network demonstrator comprising of 14 cells with a 4 m radius to investigate networking issues was
developed and key performance results are presented.
Distributed amplification in fiber-optic transmission systems is
quantitatively studied. Optimization techniques to find amplifier
parameters that maximize system performance are discussed. A
particular emphasis is given to noise properties of Raman
amplifiers and a tradeoff between the noise performance and
nonlinear impairments. It is shown that Raman amplification in
dispersion-managed fibers closely approaches the theoretical limit
of an ideal distributed amplifier and further increases the system
reach. Recent advances in the Raman-assisted ultra-long-haul
transmission are briefly reviewed.