This paper reviews and outlines the key features of the emerging next-generation fixed passive optical network (NG-PON)-based and fourth-generation (4G) mobile broadband access technologies and how to leverage the advantages of both of these access technologies to build a next-generation hybrid fiber-wireless (FiWi) network. Specifically, this paper presents an overview of the most recent research activities on these hybrid FiWi architectures, aiming to clarify the basic differences and distinguish between two FiWi networking architectural models, namely, the overlay or independent model and the truly integrated model. We then explore and present a new direction to the design and implementation of a simple and cost-effective all-packet-based converged fixed-mobile access networking solution that enables the true integration of NG-PON and 4G mobile broadband access technologies into the envisioned fixed-mobile platform. We briefly outline the general and technical requirements to support a unified NG-PON long-term evolution (LTE) radio access network (RAN) architecture that conforms to both the typically centralized fixed PON and the emerging distributed 4G mobile LTE access standards. The implementation methodology on how to efficiently and cost-effectively integrate these two access technologies along with the main advantages gained from such an integrated architecture are outlined and presented.

This paper presents heterogeneously integrated bow-tie emitter–detector photoconductive antennas (PCAs) based on low-temperature grown-gallium arsenide (LTG-GaAs) thin-film devices on silicon-dioxide/silicon (SiO ₂ /Si) host substrates for integrated terahertz (THz) systems. The LTG-GaAs thin-film devices are fabricated with standard photolithography and thermal evaporation of metal-contact layers of chromium (Cr), nickel (Ni) and gold (Au). They are etched selectively and separated from their growth GaAs substrate. The LTG-GaAs thin-film devices are then heterogeneously integrated on bow-tie antenna electrodes patterned on the surface of a SiO ₂ /Si host substrate for THz emitters and THz detectors. Cost-effective and selective integration of LTG-GaAs thin-film devices on a Si platform is demonstrated. THz radiation from the fabricated THz PCAs is successfully measured using a pump–probe THz time-domain configuration. The THz temporal duration was measured at full width half maximum of 0.36 ps. Its frequency spectrum exhibits a broadband response with a peak resonant frequency of about 0.31 THz. The demonstration illustrates the feasibility of creating heterogeneously integrated THz systems using separately optimized LTG-GaAs devices and Si based electronics.

The authors demonstrate extended flat gain bandwidth by combining Raman and parametric processes. The increase in bandwidth is accomplished by extending the Raman gain region to the longer wavelength side of the Raman gain by using parametric gain. Two different configurations of the amplifier are investigated. The associated gain and bit error performance is characterized. A gain of about 15 dB, with gain flatness of 5 dB is measured.

We have investigated the nonlinear optical response of thin films consisting of a poly(propyleneimine) dendrimer matrix having diaminobutane core with and without small $2.2\mathrm{nm}$ diameter CdS quantum dots. Large nonlinear coefficients and low nonlinear absorption losses were observed at 532 and $1064\mathrm{nm}$ . The high nonlinearity and low two-photon absorption yielded promising figures of merit for nonlinear optical switching applications.