Optical Resonators and their Applications – ORA

In the ORAproject, we propose to investigate theoretically and experimentally the realization of passive or active compact optical delay lines based on whispering gallery mode resonators as well as to study the capability of these devices to directly generate RF signal by use of third order nonlinear and/or active (Erbium doped) resonators. After the evaluation tests we will perform during the experiments planned in the current research proposal, we think we will be able to introduce these passive or active components in OEOs and in a first approach of bio-sensor systems. The research proposal presents two complementary aspects: (i) Micro-resonators and associated input/output coupler(s). (ii) Applications and their qualification tests.

In first hand, the goal is to improve theoretically and experimentally the problem of the coupling between a high-Q resonator and its external coupler. Based on modelling and simulations, the resonators and couplers will be designed, fabricated and the resulting assemblies tested by three methods well established in the previous ANR program (slow and fast frequency sweeping methods and the third derived from RF spectroscopy).
In second hand, in parallel to the works on passive (glass or mono-crystalline) micro-resonators, we will work on active optical delay line controlled by the gain based on selective amplification in Erbium doped whispering Gallery Mode resonators fabricated in glass or ceramic materials. As conclusion of the previous ANR program we have seen how the choice of the optical material is determinant to obtain a high-Q factor resonator. This task will be specifically addressed in this proposal in order to develop high purity materials as well as new materials dedicated to the fundamental and application works.

The first application will be in the following of the ANR O2E program. In this program, the results were obtained with architecture for the OEOs not very different from those studied at the JPL. The part dedicated to passive resonators will induce better knowledge and will lead to improve such kind of oscillators. The part based on selective amplification and/or nonlinearity will have as effect to develop and to study new architectures as well as generation of RF signal at higher frequency. Always based on Erbium doped resonators we will check all the characteristics (purity, stability, tenability, noise…) of a dual wavelength simultaneous emission laser source. One task will be devoted to this new component and its integration in a new topology of OEO. The applications will be declined as: “Ultra high spectral purity and high stability sources (time and frequency or radar applications)” “Resonators for millimeter wave and THz applications” “Ultra high Q resonators and systems for sensors applications”.

The results achieved in the course of the project will predominantly be published through journal publications and presented at conferences. A dedicated workshop will take place at the end of the project. This workshop (a priori a part of a European conference) would interest the Optical and Time-Frequency communities. A wiki-like cooperative environment will be set up in order to efficiently exchange between all partners, the technological background, the aims and the progress of the project. This environment will take place on the “docuwiki” platform of UMR 6082. The cooperative environment itself will be an efficient tool reserved to the partners, serving as document exchange and repository place. At the end of the project all the partners will take the decision to open or not a part of this environment.

This project takes place in the following of a previous ANR O2E n° NT05-3_45032 project.
A low phase noise microwave signal is required for many applications such as in high sensitivity radar, long-range transmission of millimeter-waves or instrumentation. The distribution of microwave signals is strongly limited due to the high losses of electrical lines. The broad bandwidth and very low loss fiber systems can be used to circumvent this issue. In this context the generation of optically carried microwaves is of great interest. The project deals with the use of whispering gallery mode to reach this issue.
Optical high quality factor (Q) micro-cavities are of great interest for applications in different fields such as optoelectronics, metrology or fundamental physics. They can be used for instance for: optical filtering, all-optical switching, low threshold non-linear optics], narrow linewidth laser applications, all-optical buffering, bio-sensing and quantum information processing or cavity quantum electrodynamics.
In the ORAproject, we propose to investigate theoretically and experimentally the realization of passive or active compact optical delay lines based on whispering gallery mode resonators as well as to study the capability of these devices to directly generate RF signal by use of third order nonlinear and/or active (Erbium doped) resonators. After the evaluation tests we will perform during the experiments planned in the current research proposal, we think we will be able to introduce these passive or active components in OEOs and in a first approach of bio-sensor systems. The research proposal presents two complementary aspects: (i) Micro-resonators and associated input/output coupler(s). (ii) Applications and their qualification tests.
In first hand, the goal is to improve theoretically and experimentally the problem of the coupling between a high-Q resonator and its external coupler. Based on modelling and simulations, the resonators and couplers will be designed, fabricated and the resulting assemblies tested by three methods well established in the previous ANR program (slow and fast frequency sweeping methods and the third derived from RF spectroscopy).
In second hand, in parallel to the works on passive (glass or mono-crystalline) micro-resonators, we will work on active optical delay line controlled by the gain based on selective amplification in Erbium doped whispering Gallery Mode resonators fabricated in glass or ceramic materials.
As conclusion of the previous ANR program we have seen how the choice of the optical material is determinant to obtain a high-Q factor resonator. This task will be specifically addressed in this proposal in order to develop high purity materials as well as new materials dedicated to the fundamental and application works.
The first application will be in the following of the ANR O2E program. In this program, the results were obtained with architecture for the OEOs not very different from those studied at the JPL. The part dedicated to passive resonators will induce better knowledge and will lead to improve such kind of oscillators. The part based on selective amplification and/or nonlinearity will have as effect to develop and to study new architectures as well as generation of RF signal at higher frequency. Always based on Erbium doped resonators we will check all the characteristics (purity, stability, tenability, noise…) of a dual wavelength simultaneous emission laser source. One task will be devoted to this new component and its integration in a new topology of OEO. The applications will be declined as: “Ultra high spectral purity and high stability sources (time and frequency or radar applications)” “Resonators for millimeter wave and THz applications” “Ultra high Q resonators and systems for sensors applications”.