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[IEEE 2019 IEEE 13th International Conference on Power Electronics and Drive Systems (PEDS) - Toulouse, France (2019.7.9-2019.7.12)] 2019 IEEE 13th International Conference on Power Electronics and Drive Systems (PEDS) - Design and optimization of a DC-DC converter for LEDs lighting applications
摘要： We thoroughly analyze the requirements on the signal and idler state of polarizations (SOPs) for achieving maximum ampli?cation in phase-sensitive ampli?ers (PSAs). These requirements are described using a Jones-space description as well as a Stokes-space description. Our analysis includes the cases of polarization-diverse and vector PSAs, and in each type of PSA, we also consider the signal-degenerate and the non-degenerate schemes. We observe that the relation between the signal and idler SOPs to achieve maximum phase-sensitive (PS) ampli?cation can be described similarly in polarization-diverse and in vector PSAs. Moreover, both types of PSAs are polarization-dependent, which means that PSAs do require polarization-tracking schemes when being implemented in a realistic optical-transmission scenario. We therefore evaluate how polarization tracking of the signal and the idler SOPs can overcome the theoretical polarization dependence of both polarization-diverse and vector PSAs. We ?nd that only one polarization tracker for either the signal or idler SOP is necessary for achieving polarization-independent PS ampli?cation when considering the general case of dual-polarization (DP) modulated signals. This polarization tracker requires the control of three degrees of freedom which describe a general polarization rotation. For single-polarization (SP) modulated signals, the polarization tracker can rotate both the signal and the idler SOPs simultaneously which eliminates the need for splitting the signal and the idler before the PSA. Moreover, only two degrees of freedom for the polarization tracker are necessary in this case. When considering degenerate schemes, a polarization tracker with two degrees of freedom is suf?cient to achieve maximum PS ampli?cation of DP binary phase-shift keying (BPSK) signals in both vector and polarization diverse PSAs. For the case of SP-BPSK signals, a polarization-diverse PSA can perform polarization-independent ampli?cation by controlling the relative phase between the pumps, whereas a polarization tracker with only one degree of freedom is necessary in the case of vector PSAs.
关键词： polarization,Optical ?ber communication,phase-sensitive ampli?ers (PSAs),parametric ampli?ers
更新于2025-09-16 10:30:52
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Eliminating Phase Drift for Distributed Optical Fiber Acoustic Sensing System with Empirical Mode Decomposition
摘要： Phase-drift elimination is crucial to vibration recovery in the coherent detection phase-sensitive optical time domain re?ectometry system. The phase drift drives the whole phase signal ?uctuation as a baseline, and its negative e?ect is obvious when the detection time is long. In this paper, empirical mode decomposition (EMD) is presented to extract and eliminate the phase drift adaptively. It decomposes the signal by utilizing the characteristic time scale of the data, and the baseline is eventually obtained. It is validated by theory and experiment that the phase drift deteriorates seriously when the length of the vibration region increases. In an experiment, the phase drift was eliminated under the conditions of di?erent vibration frequencies of 1 Hz, 5 Hz, and 10 Hz. The phase drift was also eliminated with di?erent vibration intensities. Furthermore, the linear relationship between phase and vibration intensity is demonstrated with a correlation coe?cient of 99.99%. The vibrations at 0.5 Hz and 0.3 Hz were detected with signal-to-noise ratios (SNRs) of 55.58 dB and 64.44 dB. With this method, when the vibration frequency is at the level of Hz or sub-Hz, the phase drift can be eliminated. This contributes to the detection and recovery of low-frequency perturbation events in practical applications.
关键词： phase drift elimination,phase recovery,phase-sensitive optical time domain re?ectometry,distributed acoustic sensing system,empirical mode decomposition
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Low Noise Optical Buffering Based on Non-Degenerate Phase Sensitive Parametric Amplification
摘要： Optical buffers are devices which can store optical signals for a period of time and could be valuable tools for applications such as optical storage, optical packet switching and all-optical signal processing providing the storage functionality in the optical domain, thus avoiding unwanted opto-electronic and eletro-optical conversions. During the last twenty years, there have been proposed many approaches for the implementation of optical buffers. The most straightforward scheme is the use of a fiber spool playing the role of a long-time optical delay line which requires either direct or indirect amplitude modulation to maintain the bit timing [1]. Other interesting techniques referring to optical buffering are slow-light [2], temporal solitons in optical cavities [3], excitability properties of optical devices [4] and photonic crystal nanocavities [5]. In this paper, a buffer relying on long-time optical delays supported by phase-sensitive amplification (PSA) is theoretically and numerically analysed. The scheme is compared against a buffer employing phase insensitive amplification (PIA). The buffer is studied for different levels of internal losses and in two configurations: the first considers that the PSA gain element precedes the source of losses whilst the second topology considers the opposite. Results derived from numerical simulations based on Nonlinear Schrodinger Equation (NLSE) solved with the use of split-step Fourier method taking into account polarization mode dispersion and quantum noise are also presented. The results show that the PSA enabled buffer is more robust to the accumulated noise attributed to multiple circulations in the optical cavity and can preserve the signal fidelity for hundreds of circulations, thus emerging as a promising long run buffering solution, being modulation format transparent and with the potential of multi-wavelength buffering as it will be shown in the context of the paper.
关键词： all-optical signal processing,noise figure,phase-sensitive amplification,optical storage,optical buffering
更新于2025-09-11 14:15:04
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Influence of the Laser Frequency Drift in Phase-Sensitive Optical Time Domain Reflectometry
摘要： The influence of the laser frequency drift on the operation of phase-sensitive optical time domain reflectometry (?-OTDR) systems is considered. Theoretical results based on a new numerical ?-OTDR model demonstrating the influence of the laser frequency instability on a signal are reported. This model is verified based on experimental data. It has been used to calculate the signal-to-noise ratio (SNR) of the system for different parameters of the laser source stability. As a result, quantitative requirements for lasers used in ?-OTDR systems are formulated.
关键词： laser frequency fluctuation,phase-sensitive optical time domain reflectometer,narrow-band laser,distributed sensor
更新于2025-09-11 14:15:04
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A Fluidic Biosensor Based on a Phase-Sensitive Low-Coherence Spectral-Domain Interferometer
摘要： A phase-sensitive fluidic biosensor based on a spectral-domain low-coherence interferometer is presented in this paper. With a fiber optic probe employing the common-path interferometric configuration, subnanometric changes in thickness of the molecular layers can be detected through phase analysis of the acquired interference signal from the sensor surface. Advantages of this biosensor include its picometer-scale thickness sensitivity, 13.9-ms time response, and tolerance to the fluctuation in concentration of the target solution. The capabilities of this biosensor in monitoring specific molecular binding and recognizing specific molecular was successfully demonstrated by using the reactions between the molecules of protein A and IgG. The calculated minimum detectable concentration of IgG is 0.11 μg/mL.
关键词： low-coherence spectral-domain interferometer,phase-sensitive,fluidic,immunoassays
更新于2025-09-10 09:29:36
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Time-resolved second harmonic generation with single-shot phase sensitivity
摘要： A time-resolved, phase-sensitive second harmonic generation (SHG) method to probe the excited state dynamics of interfacial species is presented. It is based on an interference measurement between the SHG from a sample and a local oscillator generated at a reference surface in which an entire interference pattern is recorded in a single shot by using a spatially varying phase unit comprised of a pair of wedges that sandwich the reference sample. In combination with 30 kHz modulation of the experiment, shot-to-shot pump-probe measurements are presented. The technique is characterised by measuring the time-resolved change in the amplitude and phase of the interference pattern due to the excited state dynamics of the dye malachite green at the air/water interface. The key attributes of the technique are its excellent phase stability and sensitivity, and relatively short data acquisition times.
关键词： air/water interface,excited state dynamics,time-resolved,second harmonic generation,malachite green,phase-sensitive,interference measurement
更新于2025-09-09 09:28:46