Search results for "Waveguide"
showing 10 items of 311 documents
Acoustically driven arrayed waveguide grating.
2015
We demonstrate compact tunable phased-array wavelength-division multiplexers driven by surface acoustic waves (SAWs) in the low GHz range. The devices comprise two couplers, which respectively split and combine the optical signal, linked by an array of single-mode waveguides (WGs). Two different layouts are presented, in which multi-mode interference couplers or free propagating regions were separately employed as couplers. The multiplexers operate on five equally distributed wavelength channels, with a spectral separation of 2 nm. A standing SAW modulates the refractive index of the arrayed WGs. Each wavelength component periodically switches paths between the output channel previously asi…
Cantor-like fractal photonic crystal waveguides
2005
Abstract We propose a new class of one-dimensional (1D) photonic waveguides: the fractal photonic crystal waveguides (FPCWs). These structures are photonic crystal waveguides (PCWs) etched with fratal distribution of grooves such as Cantor bars. The transmission properties of the FPCWs are investigated and compared with those of the conventional 1D PCWs. It is shown that the FPCW transmission spectrum has self-similarity properties associated with the fractal distribution of grooves. Furthermore, FPCWs exhibit sharp localized transmissions peaks that are approximately equidistant inside the photonic band gap.
Compact acousto-optic multimode interference device in (Al,Ga)As.
2020
Multimode interference (MMI) devices are key components in modern integrated photonic circuits. Here, we present acoustically tuned optical switches on an (Al,Ga)As platform that enable robust, compact and fast response systems improving on recently demonstrated technology. The device consists of a 2 × 2 MMI device fine-tuned in its center region by a focused surface acoustic wave (SAW) beam working in the low GHz range. In this way, we can tune the refractive index profile over a narrow modulation region and thus control the optical switching behaviour via the applied SAW intensity. Direct tuning of the MMI device avoids losses and phase errors inherent to arrayed waveguide based switches,…
Characterization of thermo-optical 2×2 switch configurations made of Dielectric Loaded Surface Plasmon Polariton Waveguides for telecom routing archi…
2012
We report on the characterization of thermo-optic switch structures based on Dielectric Loaded Surface Plasmon Polariton Waveguide for high data bit rate transfer. Performances are extracted by Leakage Radiation Microscopy and compared to numerical results.
Integration of solution processed materials in polymer waveguides
2015
Active solution processed nanomaterials have emerged as a very high promising candidates for photonic applications. The reason of this arises from the facts that they exhibit high quantum yield emission at room temperature and wavelength tunability, other than their processing involves easy and cheap fabrication techniques and a versatile integration on different substrates. In this way, active properties of different solution processed materials, as colloidal quantum dots, organic dyes and rare earth nanoparticles, have been exploited to demonstrate spontaneous emission or optical modulation in photonic devices. However, in spite of such an attractiveness of these nanomaterials, little has…
Local Metamaterial-Based Waveguides in Gaps Between Parallel Metal Plates
2009
This letter presents a new metamaterial-based waveguide technology referred to as ridge gap waveguides. The main advantages of the ridge gap waveguides compared to hollow waveguides are that they are planar and much cheaper to manufacture, in particular at high frequencies such as for millimeter and sub- millimeter waves. The latter is due to the fact that there are no mechanical joints across which electric currents must float. The gap waveguides have lower losses than microstrip lines, and they are completely shielded by metal so no additional packaging is needed, in contrast to the severe packaging problems associated with microstrip circuits. The gap waveguides are realized in a narrow …
Photo-acoustic excitation and detection of guided ultrasonic waves in bone samples covered by a soft coating layer
2012
Photo-acoustic (PA) excitation was combined with skeletal quantitative ultrasound (QUS) for multi-mode ultrasonic assessment of human long bones. This approach permits tailoring of the ultrasonic excitation and detection so as to efficiently detect the fundamental flexural guided wave (FFGW) through a coating of soft tissue. FFGW is a clinically relevant indicator of cortical thickness. An OPO laser with tunable optical wavelength, was used to excite a photo-acoustic source in the shaft of a porcine femur. Ultrasonic signals were detected by a piezoelectric transducer, scanning along the long axis of the bone, 20-50 mm away from the source. Five femurs were measured without and with a soft …
Propagation length enhancement of surface plasmon polaritons in gold nano-/micro-waveguides by the interference with photonic modes in the surroundin…
2017
Abstract In this work, the unique optical properties of surface plasmon polaritons (SPPs), i.e. subwavelength confinement or strong electric field concentration, are exploited to demonstrate the propagation of light signal at 600 nm along distances in the range from 17 to 150 μm for Au nanostripes 500 nm down to 100 nm wide (30 nm of height), respectively, both theoretically and experimentally. A low power laser is coupled into an optical fiber tip that is used to locally excite the photoluminescence of colloidal quantum dots (QDs) dispersed in their surroundings. Emitted light from these QDs is generating the SPPs that propagate along the metal waveguides. Then, the above-referred propagat…
MWP true time delay implemented in PbS-SU8 waveguides
2015
Es presenta un nou tipus de dispositiu de retard en temps real de microones (TTD) basat en la dispersió de punts quàntics col·loïdals PbS (QD) en el fotoresist SU8 disponible comercialment. Amb aquest propòsit, els nanocompostos PbS-SU8 s’integren en una plataforma de silici en forma de guies d’ones de cresta. Quan aquestes estructures es bomben a longituds d’ona per sota de l’interval de banda dels PbS QD, es realitza un desplaçament de fase en un senyal de microones transmès òpticament (a 1550 nm) i, per tant, es produeix un retard temporal. A més, es milloren els resultats mitjançant la implementació d’una nova guia d’ones de doble capa de cresta composta per un nanocompost PbS-SU8 i una…
Stable proton exchanged waveguides in Lithium Tantalate
2008
alpha, beta(1), and kappa(2) phases are investigated for planar waveguide fabrication by proton exchange in congruent lithium tantalate. The effective indices of planar waveguide eigenmodes were monitored over time, revealing that the exchange process induces aging instabilities in all phases except alpha.