Photonic Heterodyne Pixel for Imaging Arrays at Microwave and MM-Wave Frequencies

Á R Criado,D Segovia,P Acedo,C De Dios,L E García,J Montero-Depaz

doi:10.1155/2012/792571

Á R Criado, D Segovia + Show 4 more

Open Access

https://doi.org/10.1155/2012/792571

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Abstract

The use of photonic heterodyne receivers based on semiconductor optical amplifiers to be used in imaging arrays at several GHz frequencies is evaluated. With this objective, a imaging array based on such photonic pixels has been fabricated and characterized. Each of the receiving optoelectronic pixels is composed of an antipodal linear tapered slot antenna (LTSA) that sends the received RF signal directly to the electrical port of a semiconductor opticalamplifier (SOA) acting as the optoelectronic mixer. Both the local oscillator (LO) and the intermediate frequency (IF) signals are directly distributed to/from the array pixels using fiber optics, that allows for remote LO generation and IF processing to recover the image. The results shown in this work demonstrate that the performances of the optoelectronic imaging array are similar to a reference all-electronic array, revealing the possibility of using this photonic architecture in future high-density, scalable, compact imaging arrays in microwave and millimeter wave ranges.

Highlights

Microwave photonics and radio-over-fiber (RoF) techniques have been used in antenna arrays for some years typically associated with local oscillator (LO) distribution and remote intermediate frequency (IF) processing [1]
The advantages usually associated with the use of such techniques are the high bandwidth capabilities, the electromagnetic interference (EMI) immunity, the extremely low transmission losses when using optical fibers, and the possibilities of including signal processing features, like true local time delay (TTD) [2] or optical beam forming [3]
In the EO approach, which is the most interesting in terms of obtaining a photonic heterodyne mixer, one of the electrical signals involved (i.e., the local oscillator (LO) or the radiofrequency (RF)) is modulated onto an optical carrier that is delivered to the optical input of the semiconductor opticalamplifier (SOA)

Summary

Introduction

Microwave photonics and radio-over-fiber (RoF) techniques have been used in antenna arrays for some years typically associated with local oscillator (LO) distribution and remote intermediate frequency (IF) processing [1]. A portable real-time camera at 24 GHz based on this strategy has been reported [14], but the speed is reasonably good (22 frames per second) the resolution (24 × 24 pixels) is still far to be the required for the applications mentioned above, especially if we address the necessity of obtaining a portable (low-size and -weight) device In this sense, the incorporation of all-optical RF receiving pixel-based photonic mixing techniques [15] to imaging arrays will have a major impact on the resulted size, weight, and power consumption of the system. Several highfunctionality PICs have already been reported [17], especially for optical communication purposes, demonstrating that the technology is already mature to implement other functionalities With this aim, in this work we present a three by three element (3 × 3) imaging array based on a heterodyne optoelectronic pixel based on an electrooptical (EO) ultra nonlinear mixer using an ultra nonlinear semiconductor optical amplifier (XN-SOA) [15]. This antenna has a directivity in the whole band around 9 dBi-10 dBi

Imaging Array Description and Experimental Setup

Experimental Results

Conclusions