The objective of this work is to develop essential building blocks for the lab-on-a-chip optical sensing systems with high performance. In this study, the silicon-on-insulator (SOI) platform is chosen because of its compatibility with the mature microelectronics industry for the great potential in terms of powerful data processing and massive production. Despite the impressing progress in optical sensors based on the silicon photonic technologies, two constant challenges are larger sensitivity and better selectivity. To address the first issue, we incorporate porous materials to the silicon photonics platform. Two porous materials are investigated: porous silicon and porous titania. The demonstrated travelling-wave resonators with the magnesiothermically reacted porous silicon cladding have shown significant enhancement in the sensitivity. The process is then further optimized by replacing the thermal oxide with a flowable oxide for the magnesiothermic reduction. A different approach of making porous silicon using porous anodized alumina membrane leads to better flexibility in controlling the pore size and porosity. Porous titania is successfully integrated with silicon nitride resonators. To improve the selectivity, an array of integrated optical sensors are coated with different polymers, such that each incoming gas analyte has its own signature in the collective response matrix. A multiplexed gas sensor with four polymers has been demonstrated. It also includes on chip references compensating for the adverse environmental effects. On chip spectral analysis is also very critical for lab-on-a-chip sensing systems. For that matter, based on an array of microdonut resonators, we demonstrate an 81 channel microspectrometer. The demonstrated spectrometer leads to a high spectral resolution of 0.6 nm, and a large operating bandwidth of ~ 50 nm.

Photonic integration and all-optical signal processing are promising solutions to the increasing demand for high-bandwidth and high-speed communication systems. III-V semiconductor materials, specially AlGaAs, have shown potentials for photonic integration and efficient nonlinear processes due to their low nonlinear absorption, flexibility at controlling the refractive index, and mature fabrication technology. In this thesis, we report the designs of AlGaAs microring resonators optimized for efficient four-wave mixing. Four-wave mixing (FWM) is a nonlinear optical phenomenon which can be used to realize many optical signal processing operations such as optical wavelength conversion and optical time division multiplexing and demultiplexing. Our designed AlGaAs microring resonators are expected to have good optical confinement, transmission characteristics, and efficient coupling between the ring and waveguide. Here we also present our fabrication efforts to fabricate the microring resonators device and the insights gained in the process. The microring resonators devices have a potential to be used in optical communication networks for all-optical signal processing operations.

Silicon photonics is a very promising technology for future low-cost high-bandwidth optical telecommunication applications down to the chip level. This is due to the high degree of integration, high optical bandwidth and large speed coupled with the development of a wide range of integrated optical functions. Silicon-based microring resonators are a key building block that can be used to realize many optical functions such as switching, multiplexing, demultiplaxing and detection of optical wave. The ability to tune the resonances of the microring resonators is highly desirable in many of their applications. In this work, the study and application of a thermally wavelength-tunable photonic switch based on silicon microring resonator is presented. Devices with 10µm diameter were systematically studied and used in the design. Its resonance wavelength was tuned by thermally induced refractive index change using a designed local micro-heater. While thermo-optic tuning has moderate speed compared with electro-optic and all-optic tuning, with silicon’s high thermo-optic coefficient, a much wider wavelength tunable range can be realized. The device design was verified and optimized by optical and thermal simulations. The fabrication and characterization of the device was also implemented. The microring resonator has a measured FSR of ~18 nm, FWHM in the range 0.1-0.2 nm and Q around 10,000. A wide tunable range (>6.4 nm) was achieved with the switch, which enables dense wavelength division multiplexing (DWDM) with a channel space of 0.2nm. The time response of the switch was tested on the order of 10 us with a low power consumption of ~11.9mW/nm. The measured results are in agreement with the simulations. Important applications using the tunable photonic switch were demonstrated in this work. 1×4 and 4×4 reconfigurable photonic switch were implemented by using multiple switches with a common bus waveguide. The results suggest the feasibility of on-chip DWDM for the development of large-scale integrated photonics. Using the tunable switch for output wavelength control, a fiber laser was demonstrated with Erbium-doped fiber amplifier as the gain media. For the first time, this approach integrated on-chip silicon photonic wavelength control.

<p>Kerr frequency comb, a sequence of equally spaced sharp lines in frequency domain generated via four-wave mixing process, has multiple applications such as spectroscopy, metrology, and atomic clocks. Conventional frequency combs generated from mode-locked laser have the limitations of low repetition rate and large volume. One novel platform, silicon nitride (SiN) microring resonator (MRR), can overcome such disadvantages. The SiN MRR is a low loss waveguide resonator and has good reliability and capacity for on-chip integration, which enables a portable solution for Kerr frequency comb.</p><p>This thesis focuses on the design and characterization of the SiN MRR to optimize the important performance characteristics for the applications.<br></p><p>In Kerr comb applications, phase coherence between the comb lines is required to eliminate unwanted signals in the systems. Therefore, the investigation of the coherent state in MRR based comb generation can benefit the development of comb generation techniques. In particular, dark pulses exhibit much higher comb conversion efficiency than the single soliton combs.<br></p><p>The tunability of Kerr comb is another important performance characteristic of the applications, which is useful for multiple applications, such as matching the comb line spacing to the wavelength multiplexing grid for coherent communication or aligning the on-chip laser wavelength and MRR resonance frequency during the integration. The theoretic analysis of thermal tuning and experimental characterization of resonance frequency tuning via an on-chip microheater are performed in this thesis to explore the thermal tuning efficiency and its limitation.<br></p><p>Another important performance characteristics of the frequency comb is the comb bandwidth. Large bandwidth comb will be beneficial for application like dual comb spectroscopy. In addition, octave-spanning Kerr comb is desired due to its capacity of f-2f self-referencing for comb line frequencies stabilization for the applications like atomic clocks. To demonstrate on-chip octave-spanning Kerr soliton, the dispersion engineering is utilized in the device design to optimize the pump dispersion and dispersive wave generation simultaneously. The octave-spanning solitons are achieved on SiN MRRs with around 900 GHz repetition rate.<br></p><p>Finally, two optical division approaches are demonstrated to read out the large repetition rate of the octave-spanning soliton on all-SiN platform with auxiliary combs to enable the locking of undetectable repetition rate with less complexity in the fabrication and integration. The first approach uses a 25 GHz soliton; whose repetition rate is directly detectable via a photodiode. The second approach employs a Vernier scheme with an 880 GHz soliton to provide an alternative optical division scheme with lower requirements in fabrication ultrahigh Q MRRs. The divided repetition rate can be locked to enable the fully stabilization of frequency comb to provide an on-chip high stability and low noise frequency comb source.<br></p><p></p>

This thesis presents a novel method of modulating silicon photonic circuits using 3D printed microfluidic devices. The fluids that pass through the microfluidic device interact directly with the silicon waveguides. This method changes the refractive index of the waveguide cladding, thus changing the effective index of the system. Through using this technique we demonstrate the shift in resonant wavelength by a full free spectral range (FSR) by increasing the concentration of the salt water in the microfluidic device from 0% to 10%. On a 60 μm microring resonator, this equals a resonant wavelength shift of 1.514 nm when the index of the cladding changes by 0.017 refractive index units (RIU), or at a rate of 89.05 nm/RIU. These results are confirmed by simulations that use both analytical and numerical methods. This thesis also outlines the development of a process that uses two-photon absorption(TPA) in silicon to produce a photoelectrochemical (PEC) etching effect. TPA induces free carriers in silicon that then interact with the Hydroflouric Acid (HF) solution that the wafer is submerged in. This interaction removes silicon away from the wafer, which is the etching observed in our experiments. Non-line-of-sight PEC etching is demonstrated. The optical assemblies used in these experiments are presented, as are several of the results of the etching experiments.

Dans le cadre du développement de SoC (Systems-on-Chip) complexes, l'interconnexion des différent IP matériels (Intellectual Property), très distants à l'échelle d'un circuit intégré (typiquement quelques centimètres) et devant s'échanger des volumes de données parfois important, incite, pour des raisons de débit, de latence, de pertes et de consommation, l'adoption d'une méthodologie de conception adéquate pour réaliser des systèmes de plus en plus flexibles. Afin de répondre à ces nouvelles difficultés de conception, de nombreuses recherches ont fait émerger le concept de réseau optique sur puce (Optical Network-on-Chip ou ONoC).Dans cette thèse une étude détaillée d'une nouvelle architecture d'un réseau optique sur puce a été faite. La conception de ce réseau repose sur 2 paradigmes d'interconnexion: concevoir l'architecture dans le cadre d'une puce en 3D et l'empilement en plusieurs niveaux des guides d'onde optique dans la couche réseau optique sur puce. L'élément clef de cette architecture est un microrésonateur à plusieurs niveaux de guide d'onde (Si/SiO2). De ce fait, une étude détaillée sur le comportement optique de ce composant avec des modèles mathématiques et des simulations FEM a été faite dans le but d'optimiser la perte de puissance optique, le nombre des niveaux des guides d'onde empilés et la consommation d'énergie.Après avoir détaillé le fonctionnement de réseau multi-niveaux sur puce proposé "OMNoC", son protocole de routage a été étudié avec le simulateur NS-2, puis optimisé, rédiger et étudier avec C++ et l'outil Parsec Benchmark. Enfin et en tenant compte des études faites sur le comportement optique des guides d'onde et le protocole de routage, une étude desperformances comparatives avec des autres architectures a été élaborée montrant ainsi les avantages et les limites d'une telle méthodologie d'interconnexion. / The developing of complex System on Chip "SoC" interconnecting different cores IP distant in micrometer chip scale, needs important data bandwidth , low latency and the best compromise between optical power loss and crosstalk. According to that, finding new methodology design is necessary to cope to those challenges.Using centric communication becomes the mainly solution to improve communication performance in system on chip and recently many researches are focusing on Optical Network on Chip 'ONoC'.In this thesis, a novel architecture of an optical network on chip is proposed, this architecture is reposed on 2 design paradigms: ONoC based 3D chip and multilevel waveguides based ONoC. The key element of this architecture is the multilevel microresonator (Si/SiO2) which is the optical switch of the network. Optical wave behavior in different geometries have been studied using FEM method in order to find compromise between optical power loss and crosstalk. Operation mode of this ONoC called "OMNoC" is explained, routing protocol is studied using NS-2 simulator too, then optimized and developed using C++ and Benchmark tool. After that and by using FEM results and adopted routing strategy, OMNoC performances are studied and compared with other network architectures proposed in ONoC literature. In conclusion and according to performances analysis and comparisons, OMNoC could be considered as a promising network architecture which offer scalability and give a compromise between optical power loss and crosstalk.

<p>Developing a hybrid platform that combines nanophotonic circuits and atomic physic may provide new chip-scale devices for quantum application or versatile tools for exploring photon-mediated long-range quantum systems. However, this challenging project demands the excellent integration of cold atom trapping and manipulation technology with cutting-edge nanophotonics circuit design and fabrication. In this thesis project, we aim to develop a novel suspended membrane platform that serves as a quantum interface between laser-cooled, trapped atoms in an ultrahigh vacuum and the photons guided in the nanophotonic circuits based on high-quality silicon nitride microring resonators fabricated on a transparent membrane substrate. </p> <p><br></p> <p>The proposed platform meets the stringent performance requirements imposed by nanofabrication and optical physics in an ultra-high vacuum. These include a high yield rate for mm-scale suspended dielectric photonic devices, minimization of the surface roughness to achieve ultrahigh-optical quality, complete control of optical loss/in-coupling rate to achieve critical photon coupling to a microring resonator, and high-efficiency waveguide optical input/output coupler in an ultrahigh vacuum environment. This platform is compatible with laser-cooled and trapped cold atoms. The experimental demonstration of trapping and imaging single atoms on a photonic resonator circuit using optical tweezers has been demonstrated. Our circuit design can potentially reach a record-high cooperativity parameter C$>$500 for single atom-photon coupling, which is of high importance in realizing a coherent quantum nonlinear optical platform and holds great promise as an on-chip atom-cavity QED platform.</p>

La détection sensible et sélective des métaux lourds, en particulier les métaux detransition, est d’une grande importance pour la santé publique ainsi que pour la surveillancede l’environnement. Les méthodes actuelles de référence, de par leur non portabilité, limitentla possibilité de disposer de mesures à haute résolution spatiale et temporelle. Lesmicrocapteurs optiques offrent un moyen attrayant et pratique pour surmonter ces limitationsde coût global et de temps d’analyse, en permettant la mesure en temps réel sur site.Pour démontrer ce potentiel, ces travaux de thèse sont orientés sur la détermination duchrome hexavalent Cr(VI) en solution à l’aide d’une réaction colorimétrique avec le 1,5-diphénylcarbazide (DPC), permettant de créer un complexe présentant un maximumd’absorption dans le domaine du visible. Ces travaux s’inscrivent dans la volonté dedévelopper un véritable laboratoire sur puce, intégrant la fonction fluidique parélectromouillage sur diélectrique pour créer la réaction colorimétrique, ainsi que la fonctionde mesure par intégration d’un capteur optique dédié à la mesure d’absorption dans desmicrovolumes (< μL). Pour la mesure d'absorption sur de si faibles volumes, l'utilisation demicrorésonateurs vise à augmenter de façon importante le chemin optique effectif et ainsi lasensibilité du capteur.Nous décrivons nos travaux sur la conception, la fabrication de la plateformemicrofluidique digitale ainsi que du résonateur optique en anneaux à des dimensionssubmicroniques par photolithographie par projection. Les matériaux polymères sontprivilégiés pour une intégration totale bas coût à terme, ainsi qu’un substrat verre, dont lespropriétés sont particulièrement adaptées aux applications optiques dans le domaine duvisible. / The selective and sensitive detection of heavy metals, such as transition metals, is ofparamount importance for health and safety an environmental monitoring. Current referencemethods, due to their lack of portability, are limiting factors to obtain high-resolution spatialand temporal data. Optical sensors offer an attractive and convenient way to overcome theselimitations of cost and time per analysis by offering real time, on-site measurementcapabilities.In order to demonstrate this potential, this thesis is focused on the detection and quantificationof hexavalent chromium Cr(VI) in water samples by a colorimetric reaction based on areaction with the 1,5-diphenylcarbazide (DPC), that produces a complex possessing anabsorption maximum in the visible range. This works endorse the goal of creating a true labon-chip, integrating both the fluidic function based on ElectroWetting on Dielectric (EWOD)to create the colorimetric reaction, and the sensing function based on the integration of anoptical sensor able to measure absorption variations in micro-volumes (< μL). In order toobtain sufficient sensitivity on such small volumes, optical microring resonators are used inthis work, due to their ability to enhance the effective optical path length by constructiveinterferences.This thesis describes the conception and fabrication of the EWOD microfluidic platform, aswell as the conception, simulation and fabrication of submicronic microring resonators usingstepper lithography. Polymer materials and glass substrates are selected, due to their greatoptical properties in the visible range, their compatibility with the EWOD platform, and theirintegrability at a reasonable cost.

No description available.

In this thesis, we have designed and optimized strip waveguide based micro-ring and micro-ring and micro-racetrack resonators for biosensing applications. Silicon-On-Insulator (SOI) platform which offers several advantages over other materials such as Lithium Niobate, Silica on Silicon and Silicon nitride is considered here. High index contrast enables us to miniaturize the biosensor devices and monolithic integration of source and detectors on the same chip. We have considered the dispersive nature of the waveguide and proceeded towards optimization. Finite difference schemes and Finite Difference Time Domain (FDTD) methods are the primary tools used to model the biosensor. Various structures such as channel waveguides and beam structures are analyzed on the basis of their suitability for sensing applications. Strip and Rib waveguides are the two geometries considered in our studies. In an optical guiding structure, effective index of the propagating optical mode can be induced by two different phenomena: i. Homogeneous Sensing In this category, effective index of a propagating optical mode changes with uniformly distributed analytes extending over a distance well exceeding the evanescent field penetration depth. The sample serves as the waveguide cover. ii. Surface Sensing In the case of surface sensing, analytes bound to the surface of the waveguide. The effective index of an optical mode changes with the refractive index as well as the thickness of an adlayer. A thin layer of adsorbed or bound molecules transported from liquid or gaseous medium serving as waveguide cover is referred as an adlayer. Both homogeneous and surface sensing schemes are addresses in this work. By bulk sensing method, the characteristics of bioclad covering the device are studied. Optimization of the resonator structure involves the analysis of following parameters: • Gap between the ring and bus waveguides • Free spectral range • Extinction ratio • Quality factor We have achieved a maximum bulk sensitivity of 115 nm / RIU with ring waveguide width of 450 nm and bus width of 350 nm which is better than an earlier reported value of 70 nm/ RIU. We have proposed a novel detection scheme consisting of a micro-racetrack resonator formed over a cantilever structure. The devoice works on the principle of opto-mechanical coupling to detect conformational changes due to biomolecular adherence. BSA (Bovine Serum Albumin) and IgG ( Immuno Globulin G) are the two proteins considered in the work. Mechanical analysis of the beam for tensile and compressive stresses and corresponding spectral responses of the racetrack resonators are analyzed both by semi-analytical and method and numerical analyzes. We compared various aspects of rib and strip waveguide racetrack resonators. We have proved by numerical simulation, that the device is capable of distinguishing tensile and compressive stress. Two strip waveguides of dimensions : 450 nm X 220 nm and 400 nm X 180 nm, former supporting both Quasi-TE and Quasi-TM modes where as the second configuration allows only Quasi-TE mode alone. Sensitivity of the cantilever sensor is : 0.3196 x 10-3 nm/ µɛ at 1550 nm wavelength.