Miniature optoelectronic oscillators with resonators – MINOTOR

The aim of the MINOTOR project is to evaluate the feasibility and the performances of miniature, widely tunable and low phase noise opto-electronic microwave oscillators, based on the combination of specific laser sources and high-Q optical resonators.
The project mainly address the sub-theme 3.1, “generation and measure of (electromagnetic) radiations”.
Future radar and electronic warfare systems will rely on the use of a large number of radiating and receiving elements, managing an increasing operating bandwidth and dealing with more and more complex and frequency agile waveforms. In parallel, due to the growing demand on data rate, wireless telecommunication systems will require larger and larger bandwidth. The performances of these systems, will rely on the intrinsic properties of their microwave oscillators especially in terms of bandwidth, agility, spectral purity and compactness.
Purely electronic oscillators exhibit limited performances due to the lack of microwave resonators with large bandwidth, high-speed tunability, and high quality factor. Photonic technology is an attractive alternative. It offers a large operating bandwidth together with ultra-high quality factor resonators (Q>108). Low phase noise and fast tuning opto-electronic oscillator (OEO) using such resonators has been recently demonstrated at the laboratory level.
The practical application of such resonators-based tunable OEOs requires to lift several issues and to manage specific technologies, that will be addressed within the MINOTOR project, with the objective to demonstrate tunable oscillators schemes compatible with future applications requirements.
The project gather the skills in the required domains through the implication of four partners : Thales Research and Technology France (TRT-Fr, leader), the Alcatel-Thales III-V lab (3-5lab), The Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS-CNRS), and the Institut de Physique de Rennes (IPR). The proposed work is also built on the very promising results obtain in EDA project “ARAMOS”, in which have been demonstrated advanced microwave photonic components and functions.
The project is organized in three main tasks.
Within the first task, solid-state and semiconductor laser sources will be optimized in term of bandwidth, spectral purity, and self-injection capabilities, properties that are required to be used jointly with a high-Q resonator. Dual-frequency laser sources, delivering naturally an optically-carried signal, will also be optimized as they allow oscillators schemes with no modulator.
Within second task, resonators will be realized and optimized, considering two technological alternatives. Fiber-ring resonators will first be investigated. They are a simple and efficient : a record Q factor of 5 109 has already been demonstrated. They will be improved during the project, together with the investigation of non-linear effects limiting the oscillator performances and the tuning capability. Electro-optical LiNbO3 WGM compact resonators will secondly be considered as they also exhibit a high Q factor and they present promising properties in term of tunability. Coupling techniques will be studied as it is a key point for their practical application.
The third task will investigate the resonator-based OEO topologies and their modeling. Fine modeling of the whole oscillator loop taking into account linear and non-linear effects will benefit to the optimization of the laser sources and resonators.
Preferred approaches will then be selected for oscillators demonstrations, with the final objective to demonstrate at laboratory level (TRL3) an opto-electronic oscillator exhibiting the following performances :
- multi-GHz tunability, typ. 2-12 GHz,
- phase noise level below –135 dBc/Hz @10 kHz,
- tuning speed in the few tens of microsecond range,
- components compatible with a future integration into few tens of cm3 to few cm3