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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Modeling, Optimization and Power Efficiency Comparison of High-speed Inter-chip Electrical and Optical Interconnect Architectures in Nanometer CMOS Technologies

Palaniappan, Arun 2010 December 1900 (has links)
Inter-chip input-output (I/O) communication bandwidth demand, which rapidly scaled with integrated circuit scaling, has leveraged equalization techniques to operate reliably on band-limited channels at additional power and area complexity. High-bandwidth inter-chip optical interconnect architectures have the potential to address this increasing I/O bandwidth. Considering future tera-scale systems, power dissipation of the high-speed I/O link becomes a significant concern. This work presents a design flow for the power optimization and comparison of high-speed electrical and optical links at a given data rate and channel type in 90 nm and 45 nm CMOS technologies. The electrical I/O design framework combines statistical link analysis techniques, which are used to determine the link margins at a given bit-error rate (BER), with circuit power estimates based on normalized transistor parameters extracted with a constant current density methodology to predict the power-optimum equalization architecture, circuit style, and transmit swing at a given data rate and process node for three different channels. The transmitter output swing is scaled to operate the link at optimal power efficiency. Under consideration for optical links are a near-term architecture consisting of discrete vertical-cavity surface-emitting lasers (VCSEL) with p-i-n photodetectors (PD) and three long-term integrated photonic architectures that use waveguide metal-semiconductor-metal (MSM) photodetectors and either electro-absorption modulator (EAM), ring resonator modulator (RRM), or Mach-Zehnder modulator (MZM) sources. The normalized transistor parameters are applied to jointly optimize the transmitter and receiver circuitry to minimize total optical link power dissipation for a specified data rate and process technology at a given BER. Analysis results shows that low loss channel characteristics and minimal circuit complexity, together with scaling of transmitter output swing, allows electrical links to achieve excellent power efficiency at high data rates. While the high-loss channel is primarily limited by severe frequency dependent losses to 12 Gb/s, the critical timing path of the first tap of the decision feedback equalizer (DFE) limits the operation of low-loss channels above 20 Gb/s. Among the optical links, the VCSEL-based link is limited by its bandwidth and maximum power levels to a data rate of 24 Gb/s whereas EAM and RRM are both attractive integrated photonic technologies capable of scaling data rates past 30 Gb/s achieving excellent power efficiency in the 45 nm node and are primarily limited by coupling and device insertion losses. While MZM offers robust operation due to its wide optical bandwidth, significant improvements in power efficiency must be achieved to become applicable for high density applications.
82

The Double Mach-Zehnder Interferometric Hydrophone Based on a Dual Sagnac Ring Configuration

Liu, Shu-Xuan 14 July 2004 (has links)
This paper reports a reciprocal Mach-Zehnder interferometer in a dual Sagnac ring configuration, and one of two arms in Mach-Zehnder interferometer is used for underwater optic fiber hydrophone. Two Mach-Zehnder interferometers operated in opposite sense are simultaneously induced from the underwater acoustic wave and the PZT phase modulation. Thus, at the output, four interferometric beams occur such that the intensity of interferometric beams will enhance. In general, one stage of a double Mach-Zehnder interferometer is just used as a sensor, another one for compensation. Specially, this paper presents two stages of a double Mach-Zehnder interferometer sense the measurand at the same time due to the topology structure of Sagnac ring pairs. In the other words, the characteristic is to win the affection of two beauties at the same time. Two rings in the same direction make a Mach-Zehnder interferometer. Besides, the inner ring in the clockwise direction and the outer one in the counterclockwise direction also make a Mach-Zehnder interferometer. So as to the unbalanced arms of the Mach-Zehnder interferometer, the underwater acoustic wave induces the light beam phase difference in optic fiber hydrophone interrogator to demodulate the acoustic wave signal by PGC circuit.
83

Micro-fabrication of a Mach-Zehnder interferometer combining laser direct writing and fountain pen micropatterning for chemical/biological sensing applications.

Kallur, Ajay 05 1900 (has links)
This research lays the foundation of a highly simplified maskless micro-fabrication technique which involves incorporation of laser direct writing technique combined with fountain pen based micro-patterning method to fabricate polymer-based Mach-Zehnder interferometer sensor arrays' prototype for chemical/biological sensing applications. The research provides methodology that focuses on maskless technology, allowing the definition and modification of geometric patterns through the programming of computer software, in contrast to the conventional mask-based photolithographic approach, in which a photomask must be produced before the device is fabricated. The finished waveguide sensors are evaluated on the basis of their performance as general interferometers. The waveguide developed using the fountain pen-based micro-patterning system is compared with the waveguide developed using the current technique of spin coating method for patterning of upper cladding of the waveguide. The resulting output power profile of the waveguides is generated to confirm their functionality as general interferometers. The results obtained are used to confirm the functionality of the simplified micro-fabrication technique for fabricating integrated optical polymer-based sensors and sensor arrays for chemical/biological sensing applications.
84

Simulace optovláknových prvků pro senzoriku / Simulation of fiber-optic components for fiber optic sensors

Jakoubek, Petr January 2017 (has links)
This diploma thesis describes the function of commonly used elements among optical network, with an emphasis on fiber optic sensors. The basics of optical transmission and types of fibers are described, in addition to active and passive optical components, optical splitters and couplers. Optical fiber sensors are divided in two groups: intrinsic and extrinsic. Interferometric types of sensors are described in detail. The thesis compares theoretical assumptions and practical measurements of two serially-connected couplers. A~new module fulfilling real optical coupler function was made using Matlab. This module can be implemented into the VPIphotonics library. Finally, interferometric function of two serially-connected couplers was tested.
85

A Platform for a Wheeler's Delayed-Choice Experiment in Optical Fiber / En fiberoptisk plattform till Wheeler's experiment med sent val

Åhlgren, Gustaf January 2022 (has links)
Quantum mechanics has played a big role in the development of our understanding of the smallest things in the universe. It has provided descriptions for phenomena like single electrons or single photons, which are single particles of light. One of the most mysterious properties of quantum systems is the ability to behave as a particle or a wave. In 1978, J. A. Wheeler devised an experiment to investigate if a quantum system knows in advance if it should propagate as a wave or as a particle through an experiment, by changing the experiment after the quantum system has entered the experimental set-up.  Here an optical all-in fiber platform for a Wheeler's delayed choice experiment is modeled, constructed and tested using commercially available fiber optic components. This is in contrast to previous delayed choice experiments, which have used free-space components in some parts of their experimental set-up. The optical set-up was modeled and simulated using a quantum formalism, with future work in mind if the platform is used to perform a quantum delayed-choice experiment. The platform used a Sagnac interferometer as the second beamsplitter in a Mach-Zehnder interferometer, to perform the choice of measuring either particle or wave properties. Using a fiber platform, the length of the platform can easily be extended with more fiber to accommodate a large separation between the beamsplitter in the beginning of the set-up, and the Sagnac interferometer at the end of the set-up. The result was a stable platform to measure particle behavior of light with good performance, and the ability to switch between these measurements on the fly. The system was tested with classical light, but the light source can be changed from a laser, to for example an attenuated laser, to enter the quantum domain for performing a quantum delayed-choice experiment using the platform. / Kvantmekaniken har inneburit stora genombrott i vår förståelse av de allra minsta tingen i universum. Kvantmekaniken har gett oss beskrivningar av fenomen som enstaka elektroners beteende eller enstaka ljuspartiklar, så kallade fotoner. En av de märkligaste egenskaperna som finns hos subatomära partiklar är förmågan att upptärda som en våg eller som en partikel, beroende på sammanhanget. År 1978 beskrev J. A. Wheeler ett experiment för att undersöka om en kvantmekanisk partikel, till exempel en foton, vet i förväg om den skall färdas som en partikel eller som en våg genom en experimentuppställning. Undersökningen av detta görs genom att ändra experimentuppställningen samtidigt som den kvantmekaniska partikeln färdas genom uppställningen.  En fiberoptisk plattform för Wheelers experiment med sent val modelleras, byggs med kommersiella fiberoptiska komponenter och testas i denna uppsats. Detta skiljer sig från tidigare experiment som har använt frirymds optik i någon del av experimentuppställningen. Den optiska kretsen modelleras med kvantmekanikens formalism, detta för att underlätta för framtida experiment som använder plattformen för att genomföra den kvantmekaniska varianten av Wheelers experiment med sent val.  Plattformen består av en Sagnac interferometer som ersätter den andra stråldelaren i en Mach-Zehnder interferometer, och därmed ger funktionen att kunna byta mellan mätning av partikelegenskaper och mätning av vågegenskaper. Den fiberoptiska plattformen är enkel att förlänga för att skapa ett långt avstånd mellan den första stråldelaren och Sagnac interferometern. Resultatet var en stabil plattform med god förmåga att mäta partikelegenskaper respektive vågegenskaper hos ljus och byta mellan dessa mätlägen under experimentets gång. Systemet testades med klassikt laserljus men denna ljuskälla kan enkelt bytas ut mot en dämpad laser för att komma ned på ljusnivåer med enstaka fotoner, och därmed kunna genomföra den kvantmekaniska varianten av Wheelers experiment med sent val.
86

Integrated Inp Photonic Switches

May-Arrioja, Daniel 01 January 2006 (has links)
Photonic switches are becoming key components in advanced optical networks because of the large variety of applications that they can perform. One of the key advantages of photonic switches is that they redirect or convert light without having to make any optical to electronic conversions and vice versa, thus allowing networking functions to be lowered into the optical layer. InP-based switches are particularly attractive because of their small size, low electrical power consumption, and compatibility with integration of laser sources, photo-detectors, and electronic components. In this dissertation the development of integrated InP photonic switches using an area-selective zinc diffusion process has been investigated. The zinc diffusion process is implemented using a semi-sealed open-tube diffusion technique. The process has proven to be highly controllable and reproducible by carefully monitoring of the diffusion parameters. Using this technique, isolated p-n junctions exhibiting good I-V characteristics and breakdown voltages greater than 10 V can be selectively defined across a semiconductor wafer. A series of Mach-Zehnder interferometric (MZI) switches/modulators have been designed and fabricated. Monolithic integration of 1x2 and 2x2 MZI switches has been demonstrated. The diffusion process circumvents the need for isolation trenches, and hence optical losses can be significantly reduced. An efficient optical beam steering device based on InGaAsP multiple quantum wells is also demonstrated. The degree of lateral current spreading is easily regulated by controlling the zinc depth, allowing optimization of the injected currents. Beam steering over a 21 microns lateral distance with electrical current values as low as 12.5 mA are demonstrated. Using this principle, a reconfigurable 1x3 switch has been implemented with crosstalk levels better than -17 dB over a 50 nm wavelength range. At these low electrical current levels, uncooled and d.c. bias operation is made feasible. The use of multimode interference (MMI) structures as active devices have also been investigated. These devices operate by selective refractive index perturbation on very specific areas within the MMI structure, and this is again realized using zinc diffusion. Several variants such as a compact MMI modulator that is as short as 350 µm, a robust 2x2 photonic switch and a tunable MMI coupler have been demonstrated.
87

A Low-Distortion Modulator Driver With Over 6.5-Vpp Differential Output Swing and Bandwidth Above 60 GHz in a 130-nm SiGe BiCMOS Technology

Giuglea, Alexandru, Khafaji, Mohammad Mahdi, Belfiore, Guido, Henker, Ronny, Ellinger, Frank 11 June 2024 (has links)
Optimizing a modulator driver for linear and high-speed operation, while simultaneously achieving a high output voltage swing is very challenging. This paper investigates the design of a highlylinear, high-bandwidth yet power-efficient Mach-Zehnder modulator driver based on the breakdown voltage doubler concept, which overcomes the transistors' physical limitations and enables output voltage swings twice as high as conventional differential pair amplifiers can provide. The low-power design was enabled by the use of an open-collector topology for the output stage as well as by employing resistors instead of current mirrors in order to provide the bias currents for the emitter-follower (EF) stages. We show that by means of this EF implementation approach, the power consumption can be reduced by 19% without sacrificing the circuit's bandwidth and linearity. The driver achieves peak-to-peak differential output voltage swings above 6.5 Vpp,d and consumes 670mWof DC power, being one of the most power-efficient drivers in the literature. The 3-dB bandwidth is 61.2 GHz and the total harmonic distortion is 1%, measured at 1 GHz and for the output swing of 6.5 Vpp,d. To the best of the authors' knowledge, these are the highest linearity and output voltage swing reported in the literature for modulator drivers with bandwidths above 40 GHz.
88

Etude et réalisation de multiplexeurs insertion-extraction à réseaux de Bragg

Mechin, David 20 December 2001 (has links) (PDF)
L'apparition des dernières applications de l'internet à haut débit engendre une augmentation importante des échanges d'informations à travers le monde. Pour éviter une saturation inexorable du réseau de télécommunications, les liaisons par fibre optique avec multiplexage en longueur d'onde (DWDM) se généralisent pour permettre la transmission de données avec un débit actuel maximum de 1Tbit/s. L'aiguillage en longueur d'onde des signaux entre les différentes boucles de ce type de réseau est réalisé à l'aide de Multiplexeurs Insertion- Extraction (MIE). Ce mémoire est consacré à l'étude et à la réalisation de deux MIE réalisés par photoinscription de réseaux de Bragg (=filtres sélectifs en longueur d'onde photoinscrits par un champ d'interférence de lumière laser UV) dans des guides optiques à coeur dopé en germanium. Le premier MIE étudié lors de cette thèse est réalisé sur la base d'un coupleur directif en optique intégrée SiO2/Si dans la zone de couplage duquel deux réseaux de Bragg ont été photoinscrits. Le travail a consisté à améliorer à la fois la fabrication des guides optiques (diminution de leur biréfringence) ainsi que leur photoinscription (meilleure apodisation de la réponse spectrale du spectre réfléchi). La conception et la réalisation de premiers prototypes permettant l'extraction de canaux espacés de 200 GHz ont alors pu être effectuées. La deuxième étude se concentre, quant à elle, sur l'optimisation d'un MIE plus mature basé sur un interféromètre de Mach-Zehnder à réseaux de Bragg réalisé en fibre bicoeur. L'influence néfaste du déphasage engendré par les réseaux de Bragg sur la réponse spectrale de l'interféromètre a été discutée et minimisée. La reconstruction de la dispersion chromatique de ces réseaux via la réponse spectrale de l'interféromètre a aussi été étudiée. Des composants industrialisables pour réseaux d'espacements intercanaux de 100 GHz et 50 GHz ont alors pu être réalisés.
89

DPSK modulation format for optical communication using FBG demodulator / DPSK modulering för optisk kommunikation med demodulering av FBG

Jacobsson, Fredrik January 2004 (has links)
<p>The task of the project was to evaluate a differential phase shift keying demodulation technique by replacing a Mach-Zehnder interferometer receiver with an optical filter (Fiber Bragg Grating). Computer simulations were made with single optical transmission, multi channel systems and transmission with combined angle/intensity modulated optical signals. The simulations showed good results at both 10 and 40 Gbit/s. Laboratory experiments were made at 10 Gbit/s to verify the simulation results. It was found that the demodulation technique worked, but not with satisfactory experimental results. The work was performed at Eindhoven University of Technology, Holland, within the framework of the STOLAS project at the department of Electro-optical communication.</p>
90

DPSK modulation format for optical communication using FBG demodulator / DPSK modulering för optisk kommunikation med demodulering av FBG

Jacobsson, Fredrik January 2004 (has links)
The task of the project was to evaluate a differential phase shift keying demodulation technique by replacing a Mach-Zehnder interferometer receiver with an optical filter (Fiber Bragg Grating). Computer simulations were made with single optical transmission, multi channel systems and transmission with combined angle/intensity modulated optical signals. The simulations showed good results at both 10 and 40 Gbit/s. Laboratory experiments were made at 10 Gbit/s to verify the simulation results. It was found that the demodulation technique worked, but not with satisfactory experimental results. The work was performed at Eindhoven University of Technology, Holland, within the framework of the STOLAS project at the department of Electro-optical communication.

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