Tesis sobre el tema "Optical Phase Noise Measurement"
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Mukherjee, Shambo. "Development of a Fabry-Pérot optical interferometer with low thermal and accelerometric sensitivities". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCD023.
Texto completoThis thesis explores the development of a transportable, ultra-narrow linewidth laser integrating a high-finesse Fabry-Pèrot cavity made from ultra-low expansion glass with optically contacted Fused Silica mirrors, aiming to minimize thermal and mechanical perturbations and enhance frequency stability. A novel digital frequency stabilization method using an FPGA-based platform is introduced, targeting a fractional frequency stability of 1e-1 5 at 1-second integration. This approach contrasts traditional analog systems by offering increased stability and reduced complexity. The study also examines several limitations of ultra stable lasers like phase noise, thermal noise etc. and several approaches to mitigate these type of noise. Additionally, an optical frequency dissemination system using FPGA-based phaselocked loops and optical fiber links is detailed, ensuring stable signal transmission over laboratory distances
Grobbelaar, Johannes Jacobus. "Phase noise measurement". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6806.
Texto completoENGLISH ABSTRACT: The objective of the thesis is the development of a phase noise measuring system that makes use of crosscorrelation and averaging to measure below the system hardware noise floor. Various phase noise measurement techniques are considered after which the phase demodulation method is chosen to be implemented. The full development cycle of the hardware is discussed, as well as the post processing that is performed on the measured phase noise.
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is die ontwikkeling van ’n faseruis meetstelsel wat gebruik maak van kruiskorrelasie en vergemiddeling om onder die ruisvloer van die meetstelsel se hardeware te meet. Verskeie faseruis meettegnieke word ondersoek en die fase demodulasie metode word gekies om geïmplementeer te word. Die volle ontwikkelingsiklus van die hardeware word bespreek, sowel as die naverwerking wat toegepas is op die gemete faseruis.
Pham, Toan Thang. "Advances in opto-electronic oscillator operation for sensing and component characterization". Thesis, Cachan, Ecole normale supérieure, 2015. http://www.theses.fr/2015DENS0013/document.
Texto completoThe optoelectronic oscillator (OEO) was first introduced in 1996 by S. Yao and L. Maleki as a very low phase noise microwave oscillator working in direct synthesis. The OEO developments concern applications in microwave photonics, optical telecommunication, radar and high speed signal processing systems but it should also be used in the sensing domain. In this thesis, we study several aspects to apply the OEO to liquid refractive index measurement. Because of its structure the OEO is very dependent on the ambient conditions. If the OEO is not optimized and controlled, it cannot operate well for long duration. We have analyzed the influences of temperature on the electrooptic modulator (EOM) and the global OEO behavior. Temperature control can significantly reduce the drift phenomena of the EOM. In order to totally remove this drift, we have developed a complete digital system, based on a DSP kit, to detect and compensate automatically the EOM optical bias point drift and to control simultaneously its temperature. The first technique is based on a dither signal at low frequency, injected to DC electrode of the EOM. The second one is based on the average optical output power of the EOM. A combination of these two techniques can take advantages from both of them. Using like that the OEO, we have tested several configurations to measure the refractive index of four classical chemical solutions leading to a standard deviation of 3 per thousand. The results are in rather good agreement with previous publications. Finally, we have introduced a new method to improve the long-term refractive index measurement by monitoring, with a vector network analyzer, the variations of the optical delay in the fiber loop of the OEO. Introducing by this way a correction to the long-term frequency measurement it is possible to reduce the oscillation frequency fluctuations to only 606 Hz, compared to the 8 GHz of the oscillator, for a duration of 62 hours. Therefore the signal-to-noise ratio in the refractive index measurement can be enhanced and so the detection resolution of the refractive index variations during time
Azizoḡlu, Murat. "Phase noise in coherent optical communications". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13463.
Texto completoIncludes bibliographical references (p. 201-206).
by Murat AzizoÄlu.
Ph.D.
Dove, Justin (Justin Michael). "Phase-noise limitations on nonlinear-optical quantum computing". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89857.
Texto completoThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
19
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 57-58).
Flying in the face of the long-sought-after goal of building optical quantum computers, we show that traditional approaches leveraging nonlinear-optical cross phase modulation (XPM) to construct the critical element, the cphase gate - a gate which seeks to impart a [pi]-radian phase shift on a single photon pulse, conditioned on the presence of a second single photon pulse - are doomed to fail. The traditional story told in common textbooks fails to account for the continuous-time nature of the real world. Previous work addressing this fact - finding that that the proper continuous-time theory introduces fidelity-degrading phase noise that precludes such proposals - was limited in scope to the case of co-propagating pulses with equal group velocities. This left room for criticism that a high-fidelity cphase gate might be constructed using XPM with pulses that pass through each other. In our work, we build such a continuous-time quantum theory of XPM for pulses that pass through each other and evaluate its consequences. We find that fundamental aspects of the real world prevent one from constructing a perfect cphase gate, even in theory, and we show that the best we can do seems to fall far short of what is needed for quantum computation, even if we are extremely optimistic.
by Justin Dove.
S.M.
Farhoudi, Ramtin. "Study of phase noise in optical coherent systems". Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/25706.
Texto completoPhase noise is an important issue in designing today’s optical coherent systems. Although phase noise is studied heavily in wireless communications, some aspects of phase noise are novel in optical coherent systems. In this thesis we explore phase noise statistics in optical coherent systems and propose a novel technique to increase system robustness toward phase noise. Our first contribution deals with the study of phase noise statistics in the presence of electronic chromatic dispersion (CD) compensation in coherent systems. We show that previously proposed model for phase noise and CD interaction must be modified due to an overly simple model of carrier phase recovery. We derive a more accurate expression for the estimated phase noise of decision directed (DD) carrier phase recovery, and use this expression to modify the decision statistics of received symbols. We calculate bit error rate (BER) of a differential quadrature phase shift keying (DQPSK) system semi-analytically using our modified decision statistics and show that for ideal DD carrier phase recovery the semi-analytical BER matches the BER simulated via Monte-Carlo (MC) technique. We show that the semi-analytical BER is a lower bound of simulated BER from Viterbi-Viterbi (VV) carrier phase recovery for a wide range of practical system parameters. Our second contribution is concerned with adapting a multi-level coded modulation (MLCM) technique for phase noise and additive white Gaussian noise (AWGN) limited coherent system. We show that the combination of a phase noise optimized constellation with MLCM offers a phase-noise robust system at moderate complexity. We propose a numerical method to design set-partitioning (mapping bits to symbols) and optimizing code rates for minimum block error rate (BLER).We verify MLCM performance in coherent systems of 16-ary constellations impaired by nonlinear and Wiener phase noise. For nonlinear phase noise, superior performance of our MLCM design over a previously designed MLCM system is demonstrated in terms of BLER. For Wiener phase noise, we compare optimized and square 16-QAM constellations assuming either MLCM or uniform rate coding. We compare post forward error correction (FEC) BER in addition to BLER by both simulation and experiment and show that superior BLER performance is translated into post FEC BER. Our experimental post FEC BER results follow the same trends as simulated BER, validating our design.
McBride, Roy. "Phase measurement and phase control in fibre-optic interferometers". Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/1219.
Texto completoIchikawa, Hiroyuki. "Optical beam array generation with phase gratings". Thesis, Heriot-Watt University, 1991. http://hdl.handle.net/10399/807.
Texto completoKakkar, Aditya. "Frequency Noise in Coherent Optical Systems: Impact and Mitigation Methods". Doctoral thesis, KTH, Optik och Fotonik, OFO, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207072.
Texto completoQC 20170516
European project ICONE gr. #608099
Boivin, David. "Optical phase-modulated systems: numerical estimation and experimental measurement of phase jitter". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11072006-110448/.
Texto completoBennett, Gisele, Committee Member ; Rhodes, William, Committee Member ; McLaughlin, Steven, Committee Member ; Barry, John, Committee Co-Chair ; Chang, Gee-Kung, Committee Chair ; Chapman, Michael, Committee Member.
Bale, Simon. "Ultra high Q resonators and very low phase noise measurement systems for low noise oscillators". Thesis, University of York, 2012. http://etheses.whiterose.ac.uk/3159/.
Texto completoBuseck, David Allan 1963. "High-density CD-ROM readout using direct phase measurement". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276545.
Texto completoVarnum, Kent C. M. "Noncoherent detection of coherent optical heterodyne signals corrupted by laser phase noise". Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28398.
Texto completoAn error probability analysis is performed for noncoherent detection of optical heterodyne signals corrupted by laser phase noise and additive white Gaussian noise. Two types of laser modulation are investigated, on-off keying (00K) and frequency shift keying (FSK). Single user 00K system performance for different linewidth-to-bit rate ratios is analyzed over a range of both signal-to-noise ratios (SNR) and normalized decision thresholds. The decision threshold analysis illustrates which noise source dominates system performance. An analytical expression representing the effect of laser phase noise on system performance is derived based on a high user bit rate assumption. The system performance obtained with the high bit rate expression is compared with the system performance obtained with currently used expressions to determine its range of validity. An error probability analysis is then performed for noncoherent detection of FSK signals corrupted by laser phase noise and additive white Gaussian receiver noise. The performance of the FSK system is compared with the performance of the 00K system. It is shown that optical FSK systems perform better than optical 00K systems. As a demonstration of future system capability, the performance of a multiuser FSK code-division multiple access (FSK-CDMA) system is analyzed. The results obtained indicate that the application of FSK-CDMA techniques to current wavelength division multiplexed (WDM) systems can increase user capacity up to one thousand fold.
Gaudy, Thomas. "Statistical Analysis of Equalization Enhanced Phase Noise in Coherent Fiber Optical Communications". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191138.
Texto completoHuang, Zixin. "Protocols for optical quantum metrology". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18067.
Texto completoRadi, Haidar M. "Frequency hopping spread spectrum multiplexing for interferometric optical fibre sensor networks". Thesis, Manchester Metropolitan University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387483.
Texto completoLiang, Rongguang. "Measurement of optical phase and polarization in the media and systems of optical data storage". Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279811.
Texto completoChen, Zhenxiang. "The applications of ultrasonic imaging and signal processing in two-phase flow measurement". Thesis, Cranfield University, 1996. http://dspace.lib.cranfield.ac.uk/handle/1826/10516.
Texto completoPatterson, Steven Gregory. "Quantum intensity noise correlation in a Type-II phase matched optical parametric oscillator". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36977.
Texto completoIncludes bibliographical references (p. 104-105).
by Steven Gregory Patterson.
M.S.
Cardenas, Olaya Andrea. "Digital instrumentation for the measurement of high spectral purity signals". Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCD019/document.
Texto completoImprovements on electronic technology in recent years have allowed the application of digital techniques in time and frequency metrology where low noise and high accuracy are required, yielding flexibility in systems implementation and setup. This results in measurement systems with extended capabilities, additional functionalities and ease of use.The Analog to Digital Converters (ADCs) and Digital to Analog Converters (DACs), as the system front-end, set the ultimate performance of the system in terms of noise. Moreover, most commercial platforms based on FPGA are clocked by quartz oscillators whose accuracy and frequency stability are not suitable for many time and frequency applications. In this case, it is possible to take advantage of the internal Phase Locked Loop (PLL) for generating the internal clock from an external frequency reference. However, the PLL phase noise could degrade the oscillator stability thereby limiting the entire system performance becoming a critical component for digital instrumentation. The information available currently in literature, describes in depth the features of these devices at frequency offsets far from the carrier. However, the information close to the carrier is a more important concern for time and frequency applications.In this frame, my PhD work is focused on understanding the limitations of the critical blocks of digital instrumentation for time and frequency metrology. The aim is to characterize the noise introduced by these blocks and in this manner to be able to predict their effects on a specific application. This is done by modeling the noise introduced by each component and by describing them in terms of general and technical parameters. The parameters of the models are identified and extracted through the corresponding method proposed accordingly to the component operation. This work was validated by characterizing a commercially available platform, Red Pitaya. This platform is an open source embedded system whose resolution and speed (14 bit, 125 MSps) are reasonably close to the state of the art of ADCs and DACs (16 bit, 350 MSps or 14 bit, 1 GSps/3GSPs) and it is potentially sufficient for the implementation of a complete instrument. The characterization results lead to the noise limitations of the platform and give a guideline for instrumentation design techniques.Based on the results obtained from the noise characterization, the implementation of a digital instrument for frequency transfer using fiber link was performed on the Red Pitaya platform. In this project, a digital implementation for the detection and compensation of the phase noise induced by the fiber is proposed. The beat note, representing the fiber length variations, is acquired directly with a high speed ADC followed by a fully digital phase detector. Based on the characterization results, it was expected a limitation in the phase noise measurement given by the PLL. First measurements of this implementation were performed using the 150 km-long buried fibers, placed in the same cables between INRiM and the Laboratoire Souterrain de Modane (LSM) on the Italy-France border. The two fibers are joined together at LSM to obtain a 300 km loop with both ends at INRiM. From these results the noise introduced by the digital system was verified in agreement with characterization results. Further test and improvements will be performed for having a finished system which is intended to be used on the Italian Link for Frequency and Time from Turin to Florence that is 642-km long and to its extension in the rest of Italy that is foreseen in the next future.Currently, a higher performance platform is under assessment by applying the tools and concepts developed along the PhD. The purpose of this project is the implementation of a state of the art phasemeter whose architecture is based on the DAC. The DAC characterization is under development and preliminary measurements are reported here
Hurley, Paul Raymond. "Application of Optical Fiber Sensors for Quenching Temperature Measurement". Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/99035.
Texto completoMaster of Science
There are multiple types of boiling that can occur depending on the heat transfer capabilities of the system and the power applied to the coolant. The most common is nucleate boiling, where vapor produced at the surface forms bubbles and move away from the surface due to buoyancy. At a high enough power, the bubbles can coalesce into a film and lead to a point at which the liquid coolant can no longer contact the surface. Since vapor is not as effective at transferring heat from the surface, the temperature will increase drastically. In nuclear reactors, this situation (known as departure from nucleate boiling), can quickly lead to a meltdown of the fuel rods. Another important safety parameter in nuclear reactors is the minimum temperature at which this vapor film can be maintained, Tmin. This parameter is a source of significant concern with regard to accident scenarios such as LOCA (loss of coolant accident), where reintroducing coolant to the rods efficiently is of top priority. While much research has been done on nucleate and film boiling, it has been difficult to study the transition period between the two regimes due to both its transient nature and the lack of continuous measurement capabilities. Typically, temperature is measured using thermocouples, which are point-source sensors that do not allow for high spatial resolution over a large area. This thesis deals with the utilization of optical fibers for temperature measurement, which are capable of calculating data at every millimeter, potentially a much more precise measurement system than with the thermocouples. The experiments performed in this paper are quenching experiments, where a rod embedded with thermocouples and an optical fiber is heated to well above Tmin and quickly plunged into a volume of water, in order to view the transition from film to nucleate boiling.
Golubović, Boris 1967. "Basic module for an integrated optical phase difference measurement and correction system". Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/37996.
Texto completoHOLM, DAVID ALLEN. "QUANTUM THEORY OF MULTIWAVE MIXING (RESONANCE FLUORESCENCE, SATURATION SPECTROSCOPY, MODULATION, PHASE CONJUGATION, QUANTUM NOISE)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187980.
Texto completoCARDENAS, OLAYA ANDREA CAROLINA. "Digital instrumentation for the measurement of high spectral purity signals". Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2687860.
Texto completoArnison, Matthew Raphael. "Phase control and measurement in digital microscopy". Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/569.
Texto completoRizzo, Carlo Anthony Edward. "Phase retrieval near-field/far-field measurement techniques for quasi-optical large apertures". Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310888.
Texto completoAlaulamie, Arwa A. "Nanoscale Temperature Measurement of Phase Transition in Water Using Novel Optical Thermometry Techniques". Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1493904666617419.
Texto completoThompson, Michael Thomas. "Fast amplitude and delay measurement for characterization of optical devices". Texas A&M University, 2006. http://hdl.handle.net/1969.1/4440.
Texto completoArnison, Matthew Raphael. "Phase control and measurement in digital microscopy". University of Sydney. Physics, 2003. http://hdl.handle.net/2123/569.
Texto completoIglesias, Olmedo Miguel. "Impairment Mitigation in High Capacity and Cost-efficient Optical Data Links". Doctoral thesis, KTH, Optik och Fotonik, OFO, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208101.
Texto completoQC 20170602
GRIFFON
Clark, David C. "Digital Holographic Measurement of Nanometric Optical Excitation on Soft Matter by Optical Pressure and Photothermal Interactions". Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4299.
Texto completoZemba, Michael J. "Site Characterization of Phase Instability via Interferometer Measurement". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1383565461.
Texto completoDowsett, Amy. "The improvement of vehicle noise variability through the understanding of phase angle and NVH analysis methods". Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/35880.
Texto completoElliott, Timothy John. "Chromatic dispersion measurement in single-mode optical fibers by acousto-optic modulation and phase detection". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/101274.
Texto completoM.S.
Jiang, Bo. "A Wide Band Adaptive All Digital Phase Locked Loop With Self Jitter Measurement And Calibration". ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/562.
Texto completoMohammed, Abdul Rehman Ansari [Verfasser]. "Quantitative measurement of cellular dynamics using spectral domain optical coherence phase microscopy / Rehman Ansari Mohammed Abdul". Lübeck : Zentrale Hochschulbibliothek Lübeck, 2013. http://d-nb.info/1044432845/34.
Texto completoSi, Chen. "The quantitative analysis of optical phase measurement and its application to the determination of corneal birefringence". Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/38442/.
Texto completoHendawy, Mamdouh Fatt-Halla Mohamed. "The application of phase sensitive techniques to the measurement of displacement using optical position sensitive detectors". Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396406.
Texto completoGates, James Christopher. "Measurement of the local optical phase and amplitude in photonic devices using scanning near-field microscopy". Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/15469/.
Texto completoPourbahri, Babak. "Erbium-doped fibre amplifiers and their effects on the phase noise of optical carriers and radio-over-fibre signals". Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369689.
Texto completoHastings, Robert. "Use of multi-scale phase-based methods to determine optical flow in dynamic scene analysis". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2003. https://ro.ecu.edu.au/theses/1487.
Texto completoMuñoz-Arcos, Christian Daniel. "Optical Microwave Signal Generation for Data Transmission in Optical Networks". Thesis, Toulouse, ISAE, 2020. http://www.theses.fr/2020ESAE0013.
Texto completoThe massive growth of telecommunication services and the increasing global data traffic boostthe development, implementation, and integration of different networks for data transmission.An example of this development is the optical fiber networks, responsible today for theinter-continental connection through long-distance links and high transfer rates. The opticalnetworks, as well as the networks supported by other transmission media, use electricalsignals at specific frequencies for the synchronization of the network elements. The qualityof these signals is usually determined in terms of phase noise. Due to the major impact ofthe phase noise over the system performance, its value should be minimized.The research work presented in this document describes the design and implementation ofan optoelectronic system for the microwave signal generation using a vertical-cavity surfaceemittinglaser (VCSEL) and its integration into an optical data transmission system. Consideringthat the proposed system incorporates a directly modulated VCSEL, a theoreticaland experimental characterization was developed based on the laser rate equations, dynamicand static measurements, and an equivalent electrical model of the active region. This proceduremade possible the extraction of some VCSEL intrinsic parameters, as well as thevalidation and simulation of the VCSEL performance under specific modulation conditions.The VCSEL emits in C-band, this wavelength was selected because it is used in long-haullinks. The proposed system is a self-initiated oscillation system caused by internal noise sources,which includes a VCSEL modulated in large signal to generate optical pulses (gain switching).The optical pulses, and the optical frequency comb associated, generate in electricaldomain simultaneously a fundamental frequency (determined by a band-pass filter) and severalharmonics. The phase noise measured at 10 kHz from the carrier at 1.25 GHz was -127.8dBc/Hz, and it is the lowest value reported in the literature for this frequency and architecture.Both the jitter and optical pulse width were determined when different resonantcavities and polarization currents were employed. The lowest pulse duration was 85 ps andwas achieved when the fundamental frequency was 2.5 GHz. As for the optical frequencycomb, it was demonstrated that its flatness depends on the electrical modulation conditions.The flattest profiles are obtained when the fundamental frequency is higher than the VCSELrelaxation frequency. Both the electrical and the optical output of the system were integrated into an optical transmitter.The electrical signal provides the synchronization of the data generating equipment,whereas the optical pulses are employed as an optical carrier. Data transmissions at 155.52Mb/s, 622.08 Mb/s and 1.25 Gb/s were experimentally validated. It was demonstrated thatthe fundamental frequency and harmonics could be extracted from the optical data signaltransmitted by a band-pass filter. It was also experimentally proved that the pulsed returnto-zero (RZ) transmitter at 1.25 Gb/s, achieves bit error rates (BER) lower than 10−9 whenthe optical power at the receiver is higher than -33 dBm. la plus faible, 85 ps, a été obtenue lorsque la fréquence fondamentale du système était de 2,5 GHz. En ce qui concerne le peigne de fréquences optiques, il a été démontré que la formedu peigne dépend des conditions de modulation électrique et que les profils les plus platssont obtenus lorsque la fréquence fondamentale est supérieure à la fréquence de relaxationdu VCSEL. Les sorties électrique et optique du système ont été intégrées dans un émetteur optique. Lesignal électrique permet la synchronisation de l’équipement responsable de la génération desdonnées, tandis que les impulsions optiques sont utilisées comme porteuse optique. La transmissionde données à 155,52 Mb/s, 622,08 Mb/s et 1,25 Gb/s a été validée expérimentalement
Ballu, Xavier. "Measurement of equilibrium supercurrent noise in superconductor-normal ring and current-phase relation of helical hinge states of tungsten ditelluride". Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASP189.
Texto completoAn SNS junction formed by a non-superconducting material (N) between two superconducting contacts (S) can sustain a supercurrent carried by Andreev bound states (ABS) which is determined by the superconducting phase difference across the superconducting contacts. The value of this current and its dynamics are very sensitive probes of the coherent and topological transport properties in the non-superconducting material.An initial experiment in which a mesoscopic wire (Au) is inserted into a superconducting ring has made it possible to explore the dynamics of the ABS. At finite temperature, thermal fluctuations in ABS should give rise to fluctuations in the supercurrent and therefore to a finite-frequency dissipation, the amplitude of which depends on their relaxation time, as predicted by the fluctuation-dissipation theorem. By coupling this ring to a superconducting resonator, we were able to measure independently the fluctuations in the supercurrent at equilibrium and the dissipation that occurs when the ring is subjected to an oscillating magnetic flux. This experiment constitutes the first confirmation of this theorem in an SNS junction.In the second part, we demonstrated the topological character of tungsten ditelluride (WTe2) by measuring the supercurrent/phase relation using an asymmetric superconducting quantum interference device (SQUID), consisting of two SNS junctions in parallel. The sawtooth shape of the current-phase relation for a lateral facet of the crystal and the robustness of the supercurrent at high magnetic field reveals the ballistic and one-dimensional character of the transport along certain edges over more than 500 nm. This is a signature of the presence of one-dimensional states protected from disorder in this material, confirming the predictions of a phase close to a higher-order topological insulator for this material
Wang, Ziyang. "Next Generation Ultrashort-Pulse Retrieval Algorithm for Frequency-Resolved Optical Gating: The Inclusion of Random (Noise) and Nonrandom (Spatio-Temporal Pulse Distortions) Error". Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04122005-224257/unrestricted/wang%5Fziyang%5F200505%5Fphd.pdf.
Texto completoYou, Li, Committee Member ; Buck, John A., Committee Member ; Kvam, Paul, Committee Member ; Kennedy, Brian, Committee Member ; Trebino, Rick, Committee Chair. Vita. Includses bibliographical references.
Mousa, Pasandi Mohammad. "Adaptive decision-directed channel equalization and laser phase noise induced inter-carrier-inteference mitigation for coherent optical orthogonal frequency division multiplexing transport systems". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114464.
Texto completoLa croissance explosive du trafic globale sur Internet a crée une pression importante sur les réseaux optiques et les systèmes de transmission optiques; ce qui suggère le besoin de liens de transmission de haute capacité ainsi que de réseaux adaptables, reconfigurables et flexible. Les récents progrès dans les technologies de semiconducteurs métal-oxyde com-plémentaire (CMOS) ont facilité l'usage des traitements de signaux numériques (DSP) dans les systèmes de transmission optique. Grâce au retour en force du système de transmission optique cohérent ces dernières années, les systèmes de transmission optique régis par logiciel et supportés par les traitements de signaux numériques ont mené la transition fondamentale des réseaux optique inflexible vers des réseaux optique robuste, reconfigurable, prêt à brancher et utiliser.Depuis peu, le format de modulation par multiplexage fréquentiel orthogonale en optique cohérente (CO-OFDM) est profondément étudier comme format de modulation particu-lièrement prometteur pour réaliser des systèmes de transmission cohérents. Malgré le fait que les CO-OFDM aient réussi à susciter un grand intérêt dans la communauté de recherche, ils leur restent encore à avoir un impact plus tangible dans le secteur commercial. Ce non-déploiement commercial est attribué aux difficultés d'implémentations, notamment à l'information superflue excessive nécessaire et à la susceptibilité accrue aux nonlinéarités de la fibre optique et aux bruits de fréquence et de phase.Cette thèse explore certaines idées de DSP pour des systèmes de transmission CO-OFDM, incluant deux contributions originales. La première étant un égalisateur de canaux à adaptation dirigée par décision (ADDCE) qui vise à réduire l'information superflue nécessaire aux systèmes de transmission CO-OFDM. ADDCE récupère une estimation de la valeur du bruit de phase après un stage initiale de décision en extrayant et en moyennant la dérive de phase de tout les sous-canaux OFDM, ce qui démontre une compensation du bruit de phase sans information superflue. De plus, cela ajourne la matrice de transfère du canal optique symbole par symbole, offrant une réduction de l'information excédante associés avec les symboles pilotes. La seconde contribution de cette thèse se concentre sur la mitiga-tion de l'interférence inter-canaux (ICI) induite par le bruit de phase du laser dans les systèmes CO-OFDM. Ce compensateur de ICI basé sur l'interpolation estime le bruit de phase des échantillons dans le temps en utilisant une interpolation linéaire entre les estimations d'erreur de phase commune (CPE) de symboles OFDM consécutifs. Les performances des algorithmes d'égalisations appliqués en DSP mentionnés ci-haut sont étudiées en simulations et expérimentalement dans un système de transmission en CO-OFDM sur double polarisation à intervalle de garde réduite (RGI-DP-CO-OFDM), ce qui démontre une performance supérieure vis-à-vis de l'égalisateur conventionnel (CEs). Plus encore, l'analyse de la complexité des algorithmes d'égalisateurs proposées sera fournit; confirmant une implémentation à faible complexité.
Turghun, Matniyaz. "Free-space NPR mode locked erbrium doped fiber laser based frequency comb for optical frequency measurement". Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18682.
Texto completoDepartment of Physics
Brian R. Washburn
This thesis reports our attempt towards achieving a phase stabilized free-space nonlinear polarization rotation (NPR) mode locked erbium doped fiber laser frequency comb system. Optical frequency combs generated by mode-locked femtosecond fiber lasers are vital tools for ultra-precision frequency metrology and molecular spectroscopy. However, the comb bandwidth and average output power become the two main limiting elements in the application of femtosecond optical frequency combs. We have specifically investigated the free-space mode locking dynamics of erbium-doped fiber (EDF) mode-locked ultrafast lasers via nonlinear polarization rotation (NPR) in the normal dispersion regime. To do so, we built a passively mode-locked fiber laser based on NPR with a repetition rate of 89 MHz producing an octave-spanning spectrum due to supercontinuum (SC) generation in highly nonlinear fiber (HNLF). Most significantly, we have achieved highly stable self-starting NPR mode-locked femtosecond fiber laser based frequency comb which has been running mode locked for the past one year without any need to redo the mode locking. By using the free-space NPR comb scheme, we have not only shortened the cavity length, but also have obtained 5 to 10 times higher output power (more than 30 mW at central wavelength of 1570 nm) and much broader spectral comb bandwidth (about 54 nm) compared to conventional all-fiber cavity structure with less than 1 mW average output power and only 10 nm spectral bandwidth. The pulse output from the NPR comb is amplified through a 1 m long EDF, then compressed by a length of anomalous dispersion fiber to a near transform limited pulse duration. The amplified transform limited pulse, with an average power of 180 mW and pulse duration of 70 fs, is used to generate a supercontinuum of 140 mW. SC generation via propagation in HNLF is optimized for specific polling period and heating temperature of PPLN crystal for SHG around 1030 nm. At last, we will also discuss the attempt of second harmonic generation (SHG) by quasi phase matching in the periodically polled lithium niobate (PPLN) crystal due to nonlinear effect corresponding to different polling period and heating temperature.
Coronel-Rico, Juan Fernando. "Étude et réalisation d'un oscillateur à base de VCSEL verrouillé en phase pour des applications en télécommunications". Thesis, Toulouse, ISAE, 2016. http://www.theses.fr/2016ESAE0013/document.
Texto completoOscillators are present in all telecommunication systems. They synchronize the emitter and receiver of a message. The quality of the synchronization depends on the oscillator stability. To characterize the frequency domain oscillator stability, the phase noise of the carrier is used as figure of merit. An oscillator delivering a low phase noise carrier is a high spectral purity oscillator. Electronic oscillators are high performing at low frequencies. As communications systems require high data rate transmission, the electronic oscillators uses frequency multipliers that degrades the spectral purity of the carrier. The hybrid systems take advantage of the good performance of optical components at high frequency with the goal to be integrated in the electronic systems to overcome frequency limitation issues. This work use the optical injection locking technique by injecting the laser beam of a master laser inside the cavity of a VCSEL under direct modulation. The optical injection locking technique enlarges the direct modulation bandwidth of the VCSEL and reduces the Relative Intensity noise of the laser (RIN). The RIN reduction has as side effect the reduction of the additive noise inside the oscillator and, in consequence, reducing the oscillator phase noise
Panapakkam, Venkatesan Vivek. "Optical frequency comb generation using InP based quantum-dash/ quantum-well single section mode-locked lasers". Thesis, Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0024/document.
Texto completoThe increasing demand for high capacity, low cost, high compact and energy efficient optical transceivers for data center interconnects requires new technological solutions. In terms of transmitters, optical frequency combs generating a large number of phase coherent optical carriers are attractive solutions for next generation datacenter interconnects, and along with wavelength division multiplexing and advanced modulation formats can demonstrate unprecedented transmission capacities. In the framework of European project BIG PIPES (Broadband Integrated and Green Photonic Interconnects for High-Performance Computing and Enterprise Systems), this thesis investigates the generation of optical frequency combs using single-section mode-locked lasers based on InAs/InP Quantum-Dash and InGaAsP/InP Quantum-Well semiconductor nanostructures. These novel light sources, based on new active layer structures and cavity designs are extensively analyzed to meet the requirements of the project. Comprehensive investigation of amplitude and phase noise of these optical frequency comb sources is performed with advanced measurement techniques, to evaluate the feasibility of their use in high data rate transmission systems. Record Multi-Terabit per second per chip capacities and reasonably low energy per bit consumption are readily demonstrated, making them well suited for next generation datacenter interconnects
Dašovský, Jakub. "Šumové charakteristiky optického signálu zesíleného optickým vláknovým zesilovačem". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316415.
Texto completoWidjanarko, Taufiq. "Hyperspectral interferometry for single-shot profilometry and depth-resolved displacement field measurement". Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8349.
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