C. M. Campanella

Mode-splitting cloning in birefringent fiber Bragg grating ring resonators

In this Letter, we report the theoretical model and the experimental evidence of a mode-splitting cloning effect due to the resonant coupling between modes having different polarizations in weakly birefringent fiber Bragg grating (FBG) ring resonators. This modal coupling depends on the fiber birefringence and the FBG reflectivity. In the ideal case of the absence of birefringence, a single split-mode resonant structure can be observed in the resonator transmission spectrum due to the degeneracy removal of the two counter-propagating modes. In the presence of FBG birefringence, a secondary split doublet resulting in a clone of the initial one is generated. The described effect can be exploited for spectroscopic-sensing applications based on more complex split-mode dynamics.

Multiple ring resonators in optical gyroscopes

In recent years there has been an increasing research interest aimed at the development of innovative integrated optic gyroscopes. Some authors have investigated coupled-resonator waveguiding structures formed by microrings mainly for their capability of manipulating light velocity, proposing also their application in phasesensitive optic gyroscopes. In this work we analyze the main performance parameters of an integrated optic gyroscope consisting of a three coupled ring resonator structure having different radii and coupling coefficients. The main result is the enhancement of the scale factor of the multi-ring-based gyroscope, without increasing the overall footprint, with respect to a conventional single ring resonator gyro. The final sensitivity of the gyroscope is also evaluated and compared with the conventional integrated optic gyroscope configuration.

Design, Fabrication and Characterization of a New Hybrid Resonator for Biosensing Applications

A novel optical biosensor realized in SOI technology has been proposed. A preliminary study involving common configurations such as ring- and disk-resonator has been carried out in order to design and then to test the new resonator, which we call hybrid resonator because it shows ring resonator shape and an optical behavior (in terms of Q factor) similar to the one of a disk-resonator. A detection limit of 5 × 10?3 RIU has been demonstrated for the detection of glucose inside an aqueous solution.

Fibre Bragg Grating Based Strain Sensors: Review of Technology and Applications

Fibre Bragg grating (FBG) strain sensors are not only a very well-established research field, but they are also acquiring a bigger market share due to their sensitivity and low costs. In this paper we review FBG strain sensors with high focus on the underlying physical principles, the interrogation, and the read-out techniques. Particular emphasis is given to recent advances in highly-performing, single head FBG, a category FBG strain sensors belong to. Different sensing schemes are described, including FBG strain sensors based on mode splitting. Their operation principle and performance are reported and compared with the conventional architectures. In conclusion, some advanced applications and key sectors the global fibre-optic strain sensors market are envisaged, as well as the main market players acting in this field.

Hybrid Ring-Resonator Optical Systems for Nanoparticle Detection and Biosensing Applications

In this work we investigate a method to detect and size nanoparticles interacting with an optical microresonator. Quantum electrodynamics principles, i.e. quantum harmonic oscillators properties, have been employed to model the interaction between the planar resonator and a spherical nanoparticle. Preliminary results show that the proposed method and the designed resonator are well suitable for nanoparticles sizing giving a 10% error in 30nm radius nanoparticle characterization.

Optical sensor for nanoparticles

In this paper we investigate a method for the detection of nanoparticles in order to reduce the risk associated with their toxicity, by taking into account the electromagnetic characteristics and the chemical analysis of the surface of a hybrid silicon photonic microresonator. Device sensing capabilities, both optical and chemical, are optimized in order to detect and size the nanoparticle. Thus, a silicon on insulator whispering gallery mode hybrid microresonator having an outer radius of 5 µm and features that are typical of both ring and disk resonators, has been modeled. Quantum electrodynamics principles have been exploited in order to derive the master equation associated with the nanoparticle-resonator interaction. To allow a complete modeling of the sensor attention has been paid to the nanoparticle treatment, with the result that tested nanoparticles need to be chemically stabilized, monodisperse and formed by noble metal nanocolloids, in which a metal core (e.g. Au, Pd, etc) is surrounded by a monolayer or sub-monolayer film of an organic capping agent.