M. N. Armenise

Novel integrated optical beam former for phased-array antennas

We present the theoretical investigation, including design criteria, of a new optical beam former for phased-array active antennas. The device is formed by a Z-cut LiNbO3 channel- planar composite waveguide, an array of interferometric modulators and a linear microlens array. The basic element of the new architecture is the array of Mach-Zehnder Ti:liNbO3 intensity modulators having asymmetric coplanar-strip traveling-wave electrodes in which a relatively thick SiO2 buffer layer is utilized to reduce the phase velocity mismatch between the microwaves and optical waves. A comparison with other optical and electronic architectures already proposed shows a number of significant advantages. In particular, our device can be used in multichannel optical computing systems as well as in optical communication and RF signal processing systems allowing to overcome severe frequency limitations typical of devices reported in literature since it can work at frequencies greater than 30 GHz. So the very large transmission rate typical of the optical fiber communication systems may be conveniently exploited.

Recent advances in guided-wave devices for optical signal processing

A great research effort has been spent in recent years for the use of guided-wave optoelectronic technologies for signal processing in space applications, because they allow to reduce size, weight, power consumption and system complexity with respect to electronic ones. Based on these motivations, we have conceived, designed and simulated a number of original integrated optical signal processors, such as 2D correlators for imaging reconstruction in SAR applications, both airborne and spaceborne, preprocessors for data classification and identification in satellite applications for remote sensing, beam formers and steerers in active phased array antennas, heterodyne spectrum analyzers, and so on. The substrate materials considered for these circuits are both ferroelectric and III-V semiconductor materials. Original modeling and numerical techniques have been developed to analyze and design the guided-wave components included in the optical architectures. In this paper, the most significant developments of this research activity are reviewed.

Performance limits of guided-wave devices for space applications

In this paper some significant developments of guided-wave devices and recent technological advances in optoelectronics for space are described. The performance limits of these devices are highlight in terms of technological problems, power consumption, operating frequency, sizes and weight.

Quantum effects in new integrated optical angular velocity sensors

The paper describes the quantum effects to be considered in the model of new integrated optical angular velocity sensors. Integrated optics provides a promising approach to low-cost, light weight, and high performance devices. Some preliminary results are also reported.

New architecture of integrated optical data preprocessor

A large amount of data are usually transmitted, stored and processed by big digital systems in satellite remote sensing applications. To alleviate this situation, an on-board data processing system can be of significant help if it allows only the useful information data be transmitted to the ground station. To this end, a new architecture of a LiNbO3 integrated optic pre-processor is proposed in this paper. Its operation is based on the holographic substraction between two incident waves and depends on the relative phase shift. In such a way on-board identification and classification of data are allowed. The proposed device is formed by channel-planar composite waveguides to increase the number of parallel channels. Channel waveguides, which can be excited through a microlens array, allow to obtain the best performance of the electro-optic modulators, each of them is placed on a single channel waveguide, in terms of low losses and high modulation efficiency.