Multimode Single-Ring Photonic Molecule

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Coherent on-chip light sources are essential components for integrated photonics, enabling interference-based logic, high-fidelity signal routing, and precision sensing. Two-dimensional (2D) materials offer a promising platform for realizing ultracompact light sources because they combine strong excitonic effects, broad material compatibility, and efficient electrical tunability. However, achieving simultaneous optical performance and stable electrical controllability is hindered by cavity geometry and elec

Thin film lithium niobate (TFLN) combines strong second-order nonlinearity with low propagation loss, making it an ideal platform for on-chip frequency conversion and quantum light generation. Frequency conversion is usually achieved by quasi-phase matching (QPM) via electric-field poling. However, this scheme shows very high sensitivity to the dimensions of the waveguide, poling period, and duty cycle, resulting in a lack of repeatability of the phase matched wavelength and efficiency, which in turn limits

Transition metal dichalcogenides (TMDs) are semiconductor Van der Waals materials that can be obtained as stable monolayers (ML), characterized by bandgap values from visible to near infrared range. With decreasing thickness from bulk to MLs, TMDs show a transition from indirect to direct bandgap, which combined to strong exciton binding energies makes them propitious for optoelectronic applications. Their atomically flat, dangling bond free surfaces and weak interlayer van der Waals bonding enable stable e

This thesis investigates hybrid circuit quantum electrodynamics (cQED) as a versatile platform that unites superconducting resonators with semiconductor quantum dots. The central motivation is to harness strong light-matter coupling at the single-photon level, which enables coherent photon-qubit interactions and paves the way for quantum technologies in computation, communication, and sensing. The first part of this work combines hybrid cQED with holes in planar Ge/SiGe, a material system that has only rece

Optical fibres offer the possibility to realize distributed sensing, which means that each point along the fibre can separately and selectively sense quantities such as temperature, strain, acoustics, and pressure, in total similarity to a real organic nerve. The fibre can therefore distinctively inform on the position of the stimulus and on its magnitude. This unique feature makes the optical fibre actually play two essential roles: linear sensing element transducing the quantity value into an optical modu

In this work, we report about optical spectrometry using gold nano-structures printed on a polymer based integrated optical waveguide. The optical waveguide is a single mode buried waveguide, having dimensions of 3x2.2µm 2 . It is made from a combination of photo-polymerizable materials and is fabricated by photolithography on a glass substrate. To sense the electric field inside the waveguide, a gold nano-coupler array of thin lines (50 nm thick and 8 µm length) is embedded on top of the aforementioned wav

Based on a mid-infrared waveguide fabricated from Germanium on Silicon substrates, we present a concept of chemical sensors in aqueous solutions. The sensing scheme is utilizing the evanescent wave in a single-mode waveguide, and the absorption spectrum of chemicals dissolved in liquids. The waveguide is coupled to a singlemode mid-infrared quantum cascade laser [1], and an infrared detector. The wavelength of 5.81 microns is chosen to assure the specifity and sensitivity of the pilot application [2] for th

We report coupled VCSEL arrays, emitting at 1.3μm wavelength, in which both the optical gain/loss and refractive index distributions were defined on different vertical layers. The arrays were electrically pumped through a patterned tunnel junction, whereas the array pixels were realized by intra-cavity patterning using sub-wavelength air gaps. Stable oscillations in coupled modes were evidenced for 2x2 array structures, from threshold current up to thermal roll-over, using spectrally resolved field pattern

A simple physical description of the nonlinear optical interaction based on Brillouin echoes is presented. This technique makes potentially possible distributed Brillouin sensing down to centimeter spatial resolution while preserving the narrowband feature of the natural Brillouin gain spectrum. Experimental conditions for the generation of Brillouin echoes are described and demonstrations of distributed measurements using a 1 ns (10 cm) pulse are presented.

Femtosecond laser irradiation has various noticeable effects on fused silica. It can locally increase the index of refraction and modify the material chemical selectivity. Regions that have been exposed to the laser are etched hundred fold faster than unexposed regions. These effects are of practical importance from an application point-of-view and open new opportunities for the development of integrated photonics devices that combine structural and optical functions. Various observations reported in the li

Two-dimensional (2D) photonic crystals (PhCs) at near-infrared wavelengths are promising candidates for novel integrated optics applications. The main focus being on 'all PhC' monolithically integrated optical circuits. Because of well established fabrication technologies particular emphasis is on 'quasi' 2D PhCs where a 2D lattice of air holes is etched through a planar step-index waveguide providing the optical confinement in the third dimension. This approach has been successfully demonstrated both in Ga

We have employed femtosecond laser writing in order to induce refractive-index changes and waveguides in Ti3+-doped sapphire. Doping the sapphire crystal with an appropriate ion significantly reduces the threshold for creating structural changes, thus enabling the writing of waveguide structures. Passive and active buried channel waveguiding is demonstrated and images of the guided modes, propagation-loss values, fluorescence spectra, and output efficiencies are presented. The guiding area is located around

Very high frequency oscillations of intense light fields interact with micron-size dielectric objects to exert dc optical forces that allow polarizable particles to levitate, to be trapped and to be bound. Such optical forces are also suitable to arrange cold atoms in optical lattices. Various assemblages of optical traps, including periodic arrays, can be constructed either with independent lasers, or with a single laser beam split into different parts later recombined by interference, as well as through t

Thermo-optical and electro-optical (plasma dispersion) effects for silicon based integrated optical modulators are becoming attractive and effective solutions for telecommunications applications such as switching for programmable optical add-drop multiplexing for WDM. In this paper, a simple yet highly efficient novel electro-optical modulator device that exploits a SOI Schottky diode integrated in silicon rib wave-guide is proposed. Numerical 2D electrical (ATLAS©1) and 3D optical (BPM_CAD©2)simulations ar

Experimental demonstration of optical speedup at transparency (OSAT) has been performed on a 1 mm long semiconductor optical amplifiers (SOA). OSAT is a recently proposed scheme that decreases the recovery time of an SOA while maintaining the available gain. It is achieved by externally injecting into the SOA the beam of a separate high power laser at energies around the transparency point. Even though the experimental conditions were not optimal, a beam of 100 mW decreases the recovery time by a third when

We present a new technique for computing the electromagnetic field that propagates and is scattered in three-dimensional structures formed by bodies embedded in a stratified background. This fully vectorial technique is based on the Green's tensor associated with the stratified background. Its advantage lies in the fact that only the scatterers must be discretized, the stratified background being accounted for in the Green's tensor. Further, the boundary conditions at the different material interfaces as we

A new class of active fiber devices based on piezoelectric coated optical fibers is currently being developed. The piezoelectric coating is used to produce acoustic waves within the optical fiber and these acoustic waves interfere with optical signals passing through the fiber waveguide. Optical phase modulation devices based on piezoelectric coated fibers have been demonstrated and the behavior of these devices will be reviewed. A second type of active optical fiber device has been fabricated by integratin

Multimode Single-Ring Photonic Molecule

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Coherent light emission and electrical tuning of WS2-WSe2 interlayer excitons

Fabrication-tolerant modal phase matching for all-optical frequency conversion in layer-poled thin film lithium niobate waveguide

Engineering GaAs nanostructures for heterointegration with 2D transition metal dichalcogenides

Strong Charge-Photon Coupling and High-Efficiency Microwave Photodetection in Hybrid Quantum Dot-Resonator Systems

State-Of-The-Art of Research on Distributed Optical Fibre Sensors

On-chip NIR optical spectrometer based on polymeric waveguide and metallic nano-structures

Mid-infrared Waveguide Evanescent Field Chemical Sensor for Liquids

Intra-cavity patterning for mode control in 1.3μm coupled VCSEL arrays

Distributed fiber sensing using Brillouin echoes

Investigation of Femtosecond Laser Irradiation on Fused Silica

Experimental and numerical investigation of two-dimensional photonic crystals for application in integrated optics

Femtosecond-irradiation-induced refractive-index changes and channel waveguiding in bulk Ti3+: Sapphire

Building optical matter with binding and trapping forces

A Novel SOI Schottky Electro-optical Modulator for Ghz High-Speed Switching

Optical speedup at transparency of the gain recovery in semiconductor optical amplifiers

Light propagation and scattering in stratified media: a Green's tensor approach

Piezoelectric coatings for active optical fiber devices