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Microwave photonics is a rapidly-growing interdisciplinary field linking microwave and optical technologies. This paper intends to trace the evolution of microwave photonics over the last three decades emphasizing some major research areas and application fields. Currently, microwave photonics is a vivid research area with several practical applications. In this paper, we attempt to project potential future trends as well. [ABSTRACT FROM PUBLISHER]

Using the Maxwell-Bloch equations, we have studied dynamics associated with an electro-optically tunable laser modulated by a sinusoidal signal with a frequency near the cavity free spectral range. We find that frequency modulation (FM) modelocking may occur when a higher order FM mode acquires the lowest threshold. For short-cavity lasers, the pulse waveform in modelocking is complicated, and unlike the simple Gaussian shape suggested by previous studies. In order to explain instability observed in laser FM operation, we develop a linear stability analysis for the lasing FM mode. Our analysis shows that this type of instability is attributed to mode competition and to laser relaxation dynamics. We then confirm the analytic results with numerical simulations. [ABSTRACT FROM AUTHOR]

Examines the mode-locked microchip laser optical transmitter for fiber radio. Attributes of the mode-locked microchip laser; Attainment of a stable mode-locked component at the laser output; Use of the Mach-Zehnder interferometer.

Presents a hybrid lidar-radar system for underwater surveillance. Theoretical study to ascertain the ability of the hybrid scheme to improve the detection sensitivity of lidar; Design of the hybrid lidar-radar ocean experiment; Experimental set-up; Ocean experiment test results.

This article is concerned with the effect optical intensity has on the frequency response, gain, and bandwidth of the GaAs MESFET when used as an optical detector. Measurements show that the photoresponse gain can be increased by 10 dB as the optical intensity is lowered, while the bandwidth of the MESFET can be increased by an order of magnitude with an increase in optical power. [ABSTRACT FROM AUTHOR]

This paper describes a photomultiplication effect in microwave MESFETs that occurs when the device is operated close to the avalanche breakdown voltage of the drain-gate Schottky barrier. The multiplication enhances the optical response of the device, which is important when the MESFET is used in a photodetection mode. However caution is required when the device is operated at high Vds levels so that premature avalanche breakdown is avoided. [ABSTRACT FROM AUTHOR]

The dynamics of a short-cavity, electrooptically tunable microchip laser is studied using the Maxwell-Bloch equations for a unidirectional ring cavity. Within this model, the electrooptic tuning medium is treated rigorously by a wave propagation equation and the electrooptic tuning is equivalent to introducing a time varying perturbation to the boundary condition. With the help of an approximate analytic solution as well as numerical simulations, we find that the laser relaxation does not pose limitations to the intracavity frequency modulation bandwidth. Instead, the bandwidth is a sensitive function of the cavity length and also of the fraction of the cavity length taken up by the electrooptic section. In addition, under large-signal sinusoidal modulation, the numerical solutions reveal complicated dynamical behaviors when the modulation frequencies are near the cavity free spectral range. [ABSTRACT FROM AUTHOR]

Focuses on the frequency response mechanisms of gallium arsenide metal-semiconductor-metal (MSM) photodetector and electron detector. Derivation of the substrate-epitaxial layer barrier related detection process; Overview of the primary detection mechanism; Measurement of induced photo voltage in MSM terminals.

A novel optical frequency down-conversion approach employing the quadratic electrooptic effect is proposed, analyzed, and verified. This down-conversion method can seamlessly integrate with an optical phase-locked-loop linear phase demodulator. It has the potential to achieve a large dynamic range and low conversion loss. Comprehensive theoretical studies are performed to investigate the noise, efficiency, and linearity of this down-conversion approach. Experiments are then conducted. It is found that the unwanted fourth-order electrooptic effect of the InP modulator device limits the dynamic range. [ABSTRACT FROM AUTHOR]

Future communication systems will require high data rates and flexible modulation. Direct optical phase modulation of two microchip lasers by information-bearing signals allows for high-rate delivery via fiber to a basestation. At the basestation, the coherent optical signals are combined with a reference in a photodetector to produce a microwave/millimeter-wave carrier with arbitrary M-ary quadrature amplitude modulation, which can then be transmitted over a wireless channel. Rapid tuning of the microwave/millimeter-wave carrier, the modulation scheme, and the data rate is achievable through this method with no fixed oscillators at the basestation, thus providing for flexible architectures. Results show a high-quality carrier and, for 4- and 16-QAM, with data rates to 200 Mb/s. Extensions to higher data rates are discussed. [ABSTRACT FROM AUTHOR]

Examines the optical generation of a rapidly tunable millimeter-wave subcarrier for lidar--radar. Application of microwave and millimeter wave techniques in optical systems; Use of lidar in detecting objects submerged in water or embedded in tissue; Details on the methods of optical generation of a millimeter-wave subcarrier.