- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Robust 1.7-μm, all-polarization-maintaining femtosecond fiber laser source based on standard telecom fibers
摘要： We demonstrate a compact 1.7-μm all-polarization-maintaining (PM) ultrafast fiber laser source, which employs soliton self-frequency shift (SSFS) in an optical fiber as the dominant spectral-shifting mechanism. The laser generates stable pulses with 384 fs pulse width and 102 MHz repetition rate centered at 1.7 μm with 7 nm spectral bandwidth. The average power is about 35 mW with a high conversion efficiency of 66 %. The measured root mean square (RMS) output power stability over 10 hours is as low as 0.22 %. Both experimental and simulation results demonstrate that this laser has a potential to improving multiphoton imaging depth.
关键词： all-polarization-maintaining,multiphoton imaging,femtosecond fiber laser,soliton self-frequency shift,1.7-μm
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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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Kuah (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Differential Cross Spectrum Technique for Improving the Spatial Resolution of BOTDR Sensor
摘要： We propose a technique in BOTDR fiber sensor to generate a pair of pulsed probes via intensity modulation scheme for measuring distributed strain at high spatial resolution. The first probe consists of a long- and short duration of pulses separated by a short interval. The second probe only has the long pulse of the first probe. Introducing FFT in correlating the backscattered signals sampled by wide and narrow window functions for each probe gives narrow Brillouin spectrum width. The subtraction of the correlated signals obtained by the two probes results in high spatial resolution measurement. The intensity modulation makes it easier to generate the pair of pulsed probes having the same waveform of the long pulse and to obtain the results according to the measurement principle. We have achieved 0.2 m spatial resolution and 3.2 MHz Brillouin frequency accuracy in measuring a 350 m fiber.
关键词： BOTDR,spatial resolution,distributed fiber sensor,Brillouin frequency shift
更新于2025-09-23 15:23:52
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Frequency shift of an optical cavity mode due to a single-atom motion
摘要： Using quantum coherence effects, we have developed a new technique of detection of motion of single atoms or ions in an optical cavity. We have theoretically demonstrated that the presence of a single atom or ion inside cavity leads to a shift in cavity frequency and phase of transmitted probe beams. It has been shown by the use of EIT technique, the change of the phase is extremely sensitive to probe detuning in the vicinity of resonance frequency and can be in the order of 10?4.
关键词： optical cavity,frequency shift,Single-atom detector,phase shift,quantum coherence
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Detection of Uniformly Accelerated Spinning Target Based on OAM Beams
摘要： In recent years, it has been validated that electromagnetic (EM) wave carrying orbital angular momentum (OAM) can be exploited to detect the angular velocity of spinning targets with uniform velocity. In this paper, the detection method of uniformly accelerated spinning target using OAM beams is studied. The time-frequency analysis approaches, including the Wigner-Ville distribution (WVD) and the fractional order Fourier transform (FRFT), are used to analyze the rotational Doppler frequency shift caused by spinning targets. Simulation results indicate that the resolution of acceleration is dependent on the spectrum width of time-frequency diagrams of the echo signal.
关键词： OAM beams,rotational Doppler frequency shift,uniformly accelerated spinning target,Wigner-Ville distribution,fractional order Fourier transform
更新于2025-09-23 15:22:29
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2.01～ 2.42 μm all-fiber femtosecond Raman soliton generation in a heavily germanium doped fiber
摘要： We demonstrated that an all-fiber system generates high-performance mid-infrared Raman solitons in a heavily germanium doped fiber (HGDF). A 10 m-long HGDF with a 12 μm core diameter and 64 mol.% GeO2 dopant is designed and pumped by a home-made 1.96 μm femtosecond fiber laser in the strong anomalous dispersion region. Stable and single-color Raman solitons are therefore obtained with a continuous wavelength tunability from 2.01 to 2.42 μm. The pulse duration of the mid-infrared Raman solitons can be as short as ~220 fs. The efficiency of energy transfer to a Raman soliton is about 32.5%, while the maximum average power, peak power and pulse energy are up to 27 mW, 3.6 kW and ~1 nJ, respectively. Different from previous multi-color Raman or supercontinuum-like generation from HGDFs pumped in the near-zero or normal dispersion regime, such pure mid-infrared Raman solitons exhibit excellent stability with a radio-frequency signal-to-noise ratio of ~60 dB. This is, to the best of our knowledge, the first demonstration of >2.4 μm stable Raman solitons in an all-fiber system. This work may pave a path towards compact and high-performance mid-infrared femtosecond fiber laser sources.
关键词： soliton self-frequency shift,Ultrafast fiber lasers,heavily germanium doped fiber,mid-infrared
更新于2025-09-23 15:22:29
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Fiber Optic Sensors Based on Photoacoustic Effect for Rebar Corrosion Measurement
摘要： An all-optical ultrasound sensing system based on photoacoustic principle is developed to monitor and investigate the initiation of early stage steel rebar corrosion in real time. The ultrasound generator was developed by small size gold nanocomposites coated optical fibers to generate 8-MHz bandwidth signals. The ultrasound receiver was applied by a fiber Bragg grating sensor. This system was employed for the first time as a disruptive approach in order to replace the application of conventional electrical-based sensors due to their unique advantages including miniature size, lightweight, immunity to electromagnetic interference, resistance to corrosion, and distributed sensing capability. Accelerated corrosion tests were conducted on steel rebars to validate the developed sensing system. The obtained results indicated that the mass loss of corroded steel rebars was characterized by the centroid frequency shift of measured ultrasound signals. The correlation between the centroid frequency shift and the mass loss depicted an exponential relationship.
关键词： photoacoustic (PA) principle,fiber optic sensor (FOS),frequency shift,Corrosion monitoring
更新于2025-09-23 15:22:29
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Simple and ultrafast resonance frequency and dissipation shift measurements using a fixed frequency drive
摘要： A new method for determination of resonance frequency and dissipation of a mechanical oscillator is presented. Analytical expressions derived using the Butterworth-Van Dyke equivalent electrical circuit allow the determination of resonance frequency and dissipation directly from each impedance datapoint acquired at a fixed amplitude and frequency of drive, with no need for numerical fitting or measurement dead time unlike the conventional impedance or ring-down analysis methods. This enables an ultrahigh time resolution and superior noise performance with relatively simple instrumentation. Quantitative validations were carried out successfully against the impedance analysis method for inertial and viscous loading experiments on a 14.3 MHz quartz crystal resonator (QCR). Resonance frequency shifts associated with the transient processes of quick needle touches on a thiol self-assembled-monolayer functionalised QCR in liquid were measured with a time resolution of 112 μs, which is nearly two orders of magnitude better than the fastest reported quartz crystal microbalance. This simple and fast fixed frequency drive (FFD) based method for determination of resonance frequency and dissipation is potentially more easily multiplexable and implementable on a single silicon chip delivering economies of scale.
关键词： Quartz crystal microbalance,Dissipation shift,Realtime monitoring,Acoustic sensor,Resonance frequency shift,Time resolution of biomolecular process measurement
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Study on a 5.8GHz Injection-locked Magnetron for Transferring Data
摘要： It is shown that a 5.8 GHz injection-locked magnetron can transmit a digital data. We modulated a motor control signal on a 5.8 GHz signal by frequency shift keying. Utilizing injection locking method, we injected this modulated signal to a 5.8 GHz magnetron and the magnetron amplified this modulation signal as a transmitter. At the receiver, we demodulated this signal and controlled the motors. The transmitted data rate worked at 9600 bps with no bit errors. In the future, we will build this system for a wireless power and data transfer system in the same microwave bands.
关键词： frequency-shift keying,5.8GHz Magnetron,injection-locked
更新于2025-09-23 15:21:21
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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