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Large-Dynamic Frequency Response Measurement for Broadband Electro-Optic Phase Modulators
摘要： A novel method for characterizing the frequency responses of broadband electro-optic phase modulators (PMs) by employing stimulated Brillouin scattering (SBS) is proposed and experimentally demonstrated. In the proposed method, the SBS amplifies the +1st-order sideband and attenuates the -1st-order sideband of the phase-modulated signal from a PM under test. Thereby, the phase-modulated signal is converted into an optical single-sideband (OSSB) modulation signal. After square-law photodetection, the overall frequency responses are obtained. Removing the frequency responses of the SBS gain and the photodetector (PD) from the overall responses, the responses of the PM are thus achieved. Benefitting from the amplification of the SBS, the proposed method possesses a large dynamic range. Sub-Hz resolution and broadband measurement range are also achievable. A commercial broadband PM is experimentally characterized from 10 MHz to 50 GHz with a resolution of 5 MHz. According to the amplification of the SBS, the dynamic range is enhanced by 17.74 dB. The measurement result is verified by the conventional method utilizing optical spectrum analysis.
关键词： stimulated Brillouin scattering,Electrooptic modulation,Phase modulation,microwave photonics,optical variables measurement
更新于2025-11-28 14:24:03
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Self-generating Brillouin fiber laser using highly nonlinear hafnium bismuth erbium-doped fiber
摘要： A compact Brillouin fiber laser (BFL) utilizing a newly developed hafnium bismuth erbium-doped fiber (HB-EDF), which functions as both the Brillouin and linear gain media, is realized in the absence of Brillouin pump. It is achieved by the self-Brillouin generation from a 0.2 m length of HB-EDF with high nonlinearity in a laser cavity. The self-generating BFL was obtained in both ring and linear laser cavities. Compared to the ring cavity, the BFL in the linear cavity produced more Brillouin stokes at a lower pump threshold. In the experiment, an eight-line comb with average spacing of 0.087 nm was generated at the HB-EDF pump power of 75.27 mW. This compact BFL has total cavity length of less than 0.5 m, and thus, this is the shortest gain medium reported.
关键词： hafnium bismuth erbium-doped fiber,self-generating Brillouin fiber laser,stimulated Brillouin scattering
更新于2025-11-28 14:23:57
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Widely tunable single bandpass microwave photonic filter based on dual-fiber stimulated Brillouin scattering
摘要： A new technique to achieve a single bandpass microwave photonic filter (MPF) with wide tunability based on stimulated Brillouin scattering is proposed. The MPF cascades the Brillouin frequency shifter and amplification based on a dual-fiber structure. The experimental results present a single bandpass MPF located at 21.4 GHz with a 3-dB bandwidth of 38 MHz and an out-of-band rejection ratio over 30 dB. The proposed single bandpass MPF also successfully demonstrates a wide-band tuning over 40 GHz, which is achieved by employing a frequency shifter based on carrier suppressed single-sideband modulation scheme in the structure.
关键词： Brillouin frequency shift,stimulated Brillouin scattering,fiber,microwave photonic filter,carrier suppressed single-sideband modulation
更新于2025-09-23 15:23:52
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Instantaneous microwave frequency measurement with high-resolution based on stimulated Brillouin scattering
摘要： A novel photonic method of instantaneous microwave frequency measurement (IMFM) based on Stimulated Brillouin scattering (SBS) is proposed. The principle of the technique is the employment of SBS effect to amplify/attenuate two adjacent frequency components, which result in a definite amplitude comparison function (ACF). Using this technique, the frequency of an unknown RF signal can be precisely obtained. Experimental results show the measurement capability of the proposed method over a frequency range of 0.47–23 GHz with a higher resolution of 8 MHz.
关键词： Amplitude comparison functions,Microwave photonics,Instantaneous microwave frequency measurement,Stimulated Brillouin scattering
更新于2025-09-23 15:23:52
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Monitoring of Film Qualities of Amorphous SiO2 films/Si(100) Substrates by Measuring Bulk and Surface Acoustic Waves in Terms of Brillouin Spectroscopy
摘要： Acoustic properties of amorphous SiO2 thin films deposited on the Si(100) substrate were investigated by using Brillouin spectroscopy. The Brillouin spectrum was obtained by tilting the sample to investigate both the longitudinal acoustic (LA) mode and the surface acoustic wave (SAW) modes. Sound velocities of both modes, the two elastic moduli (longitudinal and shear moduli), and the Poisson ratio of the film could be obtained by combining the Brillouin data and the measured refractive index. The longitudinal sound velocity and the longitudinal elastic modulus increased with increasing Ar ratio in the Ar:O2 gas mixture, which was attributed to the better stoichiometry of the film grown at higher Ar ratio.
关键词： Brillouin scattering,Surface acoustic wave,SiO2 film
更新于2025-09-23 15:22:29
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Cross correlation peak-seeking technique of BOTDR based on the incomplete Brillouin spectrum
摘要： Considered the limitation of sweeping frequency technique, Brillouin optical time domain reflectometer (BOTDR) can only perceive slow external interference. It greatly limits the scope of application. For perceiving rapid external interference, a method of cross correlation peak-seeking technique based on incomplete Brillouin spectrum (IBS) is proposed, and the feasibility of the method is verified under the background of the monitoring of sound barriers along the high-speed railway. The numerical simulation results indicate that the probability that obtains an accurate peak frequency error within the 0.50 MHz can reach 49/50, when frequency interval for sweeping is 5 MHz and number of splicing IBS is 80. In addition, to select the optimal parameters of the system, we also take a further analysis on the effect of the splicing times and the frequency interval for sweeping on the peak detection accuracy. This method is significant to extend the application of BOTDR from slow changing fields to rapid changing fields.
关键词： Optical time domain reflectometry,Brillouin scattering,Optical fiber measurement applications
更新于2025-09-23 15:22:29
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[Advances in Intelligent Systems and Computing] Soft Computing for Problem Solving Volume 817 (SocProS 2017, Volume 2) || Temperature Resolution and Spatial Resolution Improvement of BOCDR-Based DTS System Using Particle Swarm Optimization Algorithm
摘要： Temperature resolution and spatial resolution are major performance metrics in any distributed temperature sensing (DTS) system. In this paper, we have presented a detailed analysis on the performance of a Brillouin optical correlation domain reflectometry (BOCDR)-based DTS (BOCDR-DTS) system. Particle swarm optimization (PSO) evolutionary algorithm is being used in this paper to improve the performance of the proposed BOCDR-DTS system. Using this optimization algorithm, we minimized the Brillouin frequency shift (BFS) error in sensing system. As a consequence of this, the achieved temperature and spatial resolution are ~0.839 °C and ~43 cm, respectively. The results were simulated using MATLAB version 15.0.
关键词： Spontaneous Brillouin scattering,Distributed temperature sensing,Particle swarm optimization (PSO),Temperature resolution and spatial resolution,Brillouin frequency shift,Optical correlation domain reflectometry (OCDR)
更新于2025-09-23 15:21:21
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Recent Advances in Brillouin Optical Correlation-Domain Reflectometry
摘要： Distributed ?ber-optic sensing based on Brillouin scattering has been extensively studied and many con?gurations have been developed so far. In this paper, we review the recent advances in Brillouin optical correlation-domain re?ectometry (BOCDR), which is known as a unique technique with intrinsic single-end accessibility, high spatial resolution, and cost ef?ciency. We brie?y discuss the advantages and disadvantages of BOCDR over other Brillouin-based distributed sensing techniques, and present the fundamental principle and properties of BOCDR with some special schemes for enhancing the performance. We also describe the recent development of a high-speed con?guration of BOCDR (slope-assisted BOCDR), which offers a beyond-nominal-resolution detectability. The paper is summarized with some future prospects.
关键词： Brillouin scattering,optical fiber sensing,temperature sensing,distributed sensing,structural health monitoring,optical correlation-domain reflectometry,strain sensing,nonlinear optics
更新于2025-09-23 15:21:21
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Nonlinear Optics || Stimulated Brillouin and Stimulated Rayleigh Scattering
摘要： We saw in Section 8.1 that light scattering can occur only as the result of fluctuations in the optical properties of a material system. A light-scattering process is said to be spontaneous if the fluctuations (typically in the dielectric constant) that cause the light-scattering are excited by thermal or by quantum-mechanical zero-point effects. In contrast, a light-scattering process is said to be stimulated if the fluctuations are induced by the presence of the light field. Stimulated light scattering is typically very much more efficient than spontaneous light scattering. For example, approximately one part in 105 of the power contained in a beam of visible light would be scattered out of the beam by spontaneous scattering in passing through 1 cm of liquid water. In this chapter, we shall see that when the intensity of the incident light is sufficiently large, essentially 100% of a beam of light can be scattered in a 1-cm path as the result of stimulated scattering processes.
关键词： Stimulated Rayleigh scattering,electrostriction,Stimulated Brillouin scattering,optical properties,light scattering
更新于2025-09-23 15:21:01
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SBS pulse compression using bulk fused silica by diode-pumped solid-state lasers at 1??kHz repetition rate
摘要： This study is focused on constructing a highly stable diode-pumped solid-state laser system by conducting experiments on high-repetition-rate SBS pulse compression using bulk fused silica. A multi-rod serial-connection structure is adopted for SBS expriments by comparing K8 glass and fused silica medium at a 10 Hz repetition rate. The optimized structure is obtained according to variation of the pump power density. Based on the optimized structure, fused silica-based SBS pulse compression is carried out in the range of 100–1000 Hz and the parameter performance of laser system after compression is also evaluated by comparing a HT270 liquid medium. Experimental results indicate that the energy e?ciency of fused silica-based SBS is improved by approximately 40% compared with that of K8 glass. Further, the energy relative standard deviation of fused silica-based SBS is reduced by approximately 88% compared with HT270 medium, indicating that bulk fused silica is advantageous for high-repetition-rate SBS pulse compression because of its un-?uidity, high thermal conductivity and power-load ability. In addition, a 1 kHz highly-stable sub-nanosecond compressed pulse is achieved using bulk fused silica medium at a pump energy of 50 mJ. Furthermore, the SBS energy e?ciency can be further improved by increasing the input energy.
关键词： Pulse compression,High repetition rate,Solid-state lasers,Sub-nanosecond pulse,Stimulated Brillouin scattering (SBS)
更新于2025-09-23 15:21:01