Microwave Photonic Modem Techniques for Millimeter Wave Transmitters and Receivers

Lafayette College, Easton PA

Investigators

Abstract

0140602 Jemison This proposal describes a systematic investigation into microwave-photonic techniques for the direct modulation, downconversion, and demodulation of millimeter wave signals for high-speed wireless applications such as telemedicine, multimedia distribution, and advanced satellite and military communications. Direct modulation eliminates the spurious emissions and filtering requirements associated with multiple frequency conversions, resulting in potentially increased modulation bandwidth and greater carrier tuneability. The use of photonics provides the wide bandwidth needed for direct conversion from baseband to millimeter wave frequencies and visa versa and offers the potential to significantly simplify millimeter wave transmitter and receiver architectures. Photonic transmitter and receiver approaches also are attractive since they are compatible with low-loss fiber optic distribution of millimeter wave signals prior to wireless transmission and subsequent to wireless reception. Specifically, microwave-photonic modulation/demodulation (MP-Modem) techniques that work directly at millimeter wave frequencies and can support data rates approaching 1 Gbs will be developed. The techniques will be assessed via a combination of theoretical, simulation, and experimental work. Candidate techniques will be analyzed theoretically to develop models to quantify critical performance criteria such as link gain, linearity, and bit-error-rate (BER). These models will be implemented in commercially available microwave and system-level simulation packages using a recently developed modeling approach for microwave-photonic systems. Closed loop operation of promising MP-Modem techniques will be demonstrated experimentally. The experimental work will focus on proof-of-concept demonstrations using commercially available photonic components. System-level applications that exploit the inherent wideband nature of the MP-Modem approach also will be identified and studied. These applications may include, but are not limited to, support of ultra-wideband frequency hopping spread spectrum (FHSS); support of other wideband modulation techniques (e.g. quasi-orthogonal frequency division multiplexing (quasi-OFDM) by simultaneous operation in multiple wireless bands); support of multiple modulation formats (e.g. M-ary PSK and M-ary FSK); and support of multiple access. Approaches for implementing the techniques using advanced technologies such as integrated optics and/or MEMs also will be explored. The knowledge gained from these investigations will be applied to develop a new class of transmitters and receivers that will meet the performance demands of emerging high-speed digital millimeter-wave wireless communications while providing implementation simplicity and advanced functionality that cannot be achieved via traditional electronic design techniques.