Microcavity-quality-factor enhancement using nonlinear effects close to the bistability threshold and coherent population oscillations

9 pagesInternational audienceWe analytically show that inserting a driven, two-level system inside a microcavity can improve its optical properties. In this approach, the strong dispersion induced by a pump via population oscillations increases the cavity lifetime experienced by a slightly detuned probe. We further predict that if the cavity is pumped through a resonant channel, optical absorptive or dispersive bistability can be combined with the population-oscillation-induced steep material dispersion to obtain a strong quality-factor enhancement. Moreover, differential amplification coming from the nonlinear feature of the pump transfer function can be used to drastically increase the probe transmission beyond intrinsic characteristics of the resonator. The Q-factor enhancement and the differential amplification can be advantageously combined with a frequency pulling effect to stabilize or readjust the microcavity resonance frequency

Characterization of Few Mode Fibers by OLCI Technique

International audienceAll LP modes of a few mode fiber are simultaneously characterized using phase-sensitive optical low-coherence interferometry. The differential modal group delay and absolute chromatic dispersion values of each mode are retrieved from a single measurement without spatial mode transformers

Controling the coupling properties of active ultrahigh-Q WGM microcavities from undercoupling to selective amplification

International audienceUltrahigh-quality (Q) factor microresonators have a lot of applications in the photonics domain ranging from low-threshold nonlinear optics to integrated optical sensors. Glass-based whispering gallery mode (WGM) microresonators are easy to produce by melting techniques, however they suffer from surface contamination which limits their long-term quality factor to a few 10^8 . Here we show that an optical gain provided by erbium ions can compensate for residual losses. Moreover it is possible to control the coupling regime of an ultrahigh Q-factor three port microresonator from undercoupling to spectral selective amplification by changing the pumping rate. The optical characterization method is based on frequency-swept cavity-ring-down- pectroscopy. This method allows the transmission and dispersive properties of perfectly transparent microresonators and intrinsic finesses up to 4.0x10^7 to be measured. Finally we characterize a critically coupled fluoride glass WGM microresonator with a diameter of 220 mm and a loaded Q-factor of 5.3x10^9 is demonstrated

Versatile Graded-Index Multi-Mode Fiber for High Capacity Single-and Multi-Mode Optical Home Network

International audienceA graded-index multi-mode fiber has been optimized to sustain a single excited mode when coupled with a standard single-mode fiber at 1310/1550nm while offering large effective modal bandwidth at 850nm under VCSEL excitations. Modeling and experimental results are presented

Etude de Composants Absorbants Saturables à Semi-Conducteurs à Multi-Puits Quantiques Dopés au Fer pour la Régénération de Signaux Optiques à Très Hauts Débits d'Information

In this document, we present a study of Fe-doped multi-quantum well saturable absorber characteristics for high-bit-rate signal all-optical 2R regeneration. We discuss nonlinear properties which allow the use of such a device as a regenerator as well as applications in optical telecommunications. Then, we propose experimental methods and results relating to Fabry-Perot cavity saturable absorber characteristics. We also study the changes in the properties of the device (contrast, wavelength, response time and threshold power of nonlinear effects) with respect to temperature and incident signal polarization. Finally, we propose the first results of the performance of this component at a transmission bit rate of 10Gbit/s in an 91 km recirculation loop.Dans ce document, nous présentons une étude des caractéristiques d'absorbants saturables à multi-puits quantiques dopés au fer dans le cadre d'une régénération 2R tout optique de signaux à hauts débits. Après avoir situé le domaine d'application et rappelé les propriétés non-linéaires du matériau qui permettent l'utilisation de ces structures en tant que régénérateurs pour les télécommunications optiques. Nous exposons les méthodes de caractérisation et les résultats expérimentaux concernant ce composant, en s'intéressant plus particulièrement à des absorbants saturables insérés en cavité Fabry-Perot. Puis, nous étudions l'évolution des propriétés (longueur d'onde, contraste, temps de réponse et puissance optique de seuil des effets non-linéaires) en fonction de la polarisation du signal incident et de la température. Enfin, nous proposons les résultats préliminaires des performances de ce composant en configuration système à 10Gbit/s dans une boucle à recirculation de 91 kilomètres

Etude de composants absorbants saturables à semi-conducteurs à multi-puits quantiques dopés au fer pour la régénération de signaux optiques à très hauts débits d'information

Dans ce document, nous présentons une étude des caractéristiques d'absorbants saturables à multi-puits quantiques dopés au fer dans le cadre d'une regeneration 2R tout optique de signaux à hauts débits. Après avoir situé le domaine d'application et rappelé les propriétés non-linéaires du matériau qui permettent l'utilisation deces structures en tant que régénérateurs pour les télécommunications optiques.Nous exposons les méthodes de caractérisation et les résultats expérimentaux concernant cecomposant, en s'intéressant plus particulièrement à des absorbants saturables insérés en cavité Fabry-Perot.Puis, nous étudions l'évolution des propriétés(longueurd'onde, contraste, temps de réponse et puissance optique de seuil des effets non-linéaires) en fonction de la polarisation du signal incident et de la température. Enfin, nousproposons les résultats préliminaires des performances de ce composant en configuration système à 10Gbit/s dans une boucle à recirculation de 91 kilomètres.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

2R Regeneration Study in a Microcavity with a Saturable Absorber

International audienceWe theoretically study the dynamical response of a saturable absorber (SA) in a microcavity realizing a non-linear mirror (NLM). We compare the effects of the SA response time on the extinction ratio of a single pulse crossing a single NLM and a two NLM based device. We also study 2R regeneration of a 40 Gbit/s pulses train with a single NLM

A simple model system to study coupled photonic crystal microcavities

International audienceWe have designed and experimentally studied several systems of standard coaxial cables with different impedances which mimic the operation of so-called photonic structures like coupled photonic crystal microcavities. Using elementary cells of half-meter long coaxial cables, we got resonances around 100 MHz, a range of frequencies that can be easily studied with standard teaching laboratory apparatus. Resonant mode frequency splitting has been obtained in the case of double and triple coupled cavities. Good agreement between experimental results and the transfer matrix model has been observed. The aim here is to demonstrate that a standard coaxial cable system is a very cheap and easy to implement structure to explain to undergraduate students complex phenomena that usually occur in the optical domain. © 2021 Author(s)

Observation of thermal effects due to an optical incident signal and high fluence on InGaAs/InP multiple-quantum-well saturable absorber nonlinear mirrors: evolution of characteristics and time constants

Topic "Lasers, Photonics, and Environmental Optics : Optical devices"International audienceWe observe the effects of a temperature increase on the characteristics of an InGaAs/InP multiple-quantum-well (MQW) saturable absorber (SA) in a microcavity provided by an optical input signal under normal incidence. The temperature increase on the nonlinear mirror (NLM) due to an optical signal depends on the energy time filling factor (FF) of this input signal (analogous to the signal's duty cycle, which is the ratio between the repetition period and the pulse duration) and hence depends on the repetition rate of the signal for a given pulse time width. This increase in temperature is mostly responsible for a shift in the reflectivity spectrum of the device toward higher wavelengths. In this experimental study, we show the shift of the resonance cavity versus the optical input power at high FF, and we evaluate the thermal time constant of an Fe-doped InGaAs/InP MQW NLM. Finally, we report the consequences of such thermal effects and high fluence on the reflectivity and contrast of two different InGaAs/InP NLMs when the input signal FF rises up to 25%, which gets close to telecommunication transmission conditions