Broadband and low loss capability of photonics has led to an ever-increasing interest in its use for the generation, processing, control and distribution of microwave and millimeter-wave signals for applications such as broadband wireless access networks, sensor networks, radar, satellite communitarians, instrumentation and warfare systems. In this tutorial, techniques developed in the last few years in microwave photonics are reviewed with an emphasis on the systems architectures for photonic generation and processing of microwave signals, photonic true-time delay beamforming, radio-over-fiber systems, and photonic analog-to-digital conversion. Challenges in system implementation for practical applications and new areas of research in microwave photonics are also discussed.

Microwave Photonics

Microwave photonics is an area that studies the generation, processing, control and transmission of microwave signals by means of photonics. In this paper, microwave photonics techniques developed in the past few years will be reviewed, with an emphasis on system architectures for microwave applications.

http://ieeexplore.ieee.org/iel5/6305327/6320324/06320333.pdf

Microwave photonics

We have studied RF transmission over various multimode fibers (MMFs) and a standard single-mode fiber, targeting picocellular networks for voice, data, and video applications. Bandwidth requirements of MMF links that are based on vertical-cavity surface-emitting laser (VCSEL) have been extensively studied. The performance of the radio-over-fiber link is assessed in terms of the error vector magnitude. Also conducted was a full system analysis, including the investigation of an achievable dynamic range and a noise figure for different low-cost architectures. This was compared to coax-based RF transmission. The IEEE 802.11 a/b/g standard, as well as other applications like radio frequency identification tracking, was considered. For experimental investigations, we have used both commercial wireless access points and a vector signal generator as a signal source, with two types of directly modulated VCSELs - 850-nm sources and 1310-nm high-speed uncooled single-mode AlGaInAs/InP VCSELs. A robust system performance was demonstrated in both 2.4- and 5-GHz RF bands, and record multimode and standard single-mode fiber transmission distances were achieved. A transponder design that can meet system requirements in terms of sensitivity ( 95 dBldrHz2/3) for a dual-band wireless LAN (WLAN) fiber-radio picocellular network was developed. A full 14-cell experimental WLAN system with cells of 4-m radius was implemented to study networking issues such as handoff and cochannel interference.

Radio Over Fiber for Picocellular Network Architectures

Hybrid fiber-wireless (FiWi) access networks aim at combining the huge amount of available bandwidth of optical networks and the ubiquity and mobility of wireless access networks with the objective to reduce their cost and complexity. This article highlights key enabling optical as well as wireless technologies and explains their role in emerging FiWi networks. After briefly reviewing previous art, important challenges and imperatives for the design of future FiWi network architectures, protocols, and algorithms are identified and discussed in detail.

Fiber-wireless (FiWi) access networks: Challenges and opportunities

Microwave to mm-wave radio carriers are commonly employed for creating high-capacity picocell wireless networks. Advanced radio-over-fiber (RoF) techniques can efficiently generate and transport such carriers, and deliver them to simplified antenna stations. As in in-building networks multimode fiber is predominantly used, adequate radio-over-multimode fiber (RoMMF) techniques are required to overcome the modal dispersion in multimode fiber links. The optical frequency multiplying technique is introduced; it is relatively simple to implement, yet it is shown to be robust against the modal dispersion, and it is able to generate very pure microwave carriers while requiring only moderate speed electronics. Thus, it can convey high data rates in comprehensive modulation formats on multiple-GHz carriers in MMF networks. It offers simultaneous operation at multiple radio standards, and capabilities for dynamic adaptation of the radio link parameters such as carrier frequency, transmit power, and other antenna site functions by means of an embedded control channel. Moreover, in combination with optical routing it enables dynamically adjustable network configurations for flexible wireless service delivery.

/pdf/radio-over-mmf-techniques-part-ii-microwave-to-millimeter-3wm07uvq8a.pdf

Radio-Over-MMF Techniques—Part II: Microwave to Millimeter-Wave Systems

A low-cost option for transporting global system for mobile communication, Universal Mobile Telecommunication System and wideband local area network (WLAN) signals using multimode fiber (MMF) with 850-nm vertical-cavity surface-emitting lasers (VCSELs) is investigated through range predictions from a link budget analysis. These predictions are experimentally verified for WLAN signal transmission in an office environment, using a commercial access point and a 300-m (OM1/OM2) MMF link with low-cost 850-nm VCSEL transmitters. The analysis indicates that good performance and signal coverage is possible with optimum design of indoor fiber-fed wireless systems, even when using such inexpensive components

/pdf/design-of-low-cost-multimode-fiber-fed-indoor-wireless-55s2ona7i8.pdf

Design of low-cost multimode fiber-fed indoor wireless networks

Performance measurements of different combinations of digital enhanced cordless telecommunications packet radio service, global system for mobile communications, universal mobile telecommunication service, and 802.11g (54 Mbps) signals in a dual band configuration transmitted over an indoor wireless network fed by a low-cost 850-nm vertical-cavity surface-emitting laser (VCSEL)-300m multimode fiber link are presented. The feasibility of such a system is demonstrated with error vector magnitude measurements which are within the required specifications

/pdf/simultaneous-dual-band-transmission-over-multimode-fiber-fed-3rcjomvhzm.pdf

I.J. Garcia

Papers

Design of low-cost multimode fiber-fed indoor wireless networks

Simultaneous Dual Band Transmission Over Multimode Fiber-Fed Indoor Wireless Network