- 标题
- 摘要
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- 实验方案
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Tailoring Properties of Microcavity In-line Mach-Zehnder Interferometer by the Microcavity Enlargement using Femtosecond Laser
摘要： This work presents a theoretical analysis and experimental verification of fine-tuning of the spectral response and refractive index (RI) sensitivity of microcavity in-line Mach-Zehnder interferometer (μIMZI). The μIMZIs were fabricated using femtosecond (fs) laser micromachining in standard single-mode fibers as circular cavities with a diameter of 60 μm. Next, the structures underwent fs laser post-processing, which included fabrication of an additional cavity with the same diameter but shifted by 15 μm or 30 μm against the center of the initial microcavity. Different depths of the additional structures were investigated. The enlargement of the microcavity allows for tailoring the spectral response, i.e., it shifts the interference pattern by more than 200 nm, with no introduction of any additional losses and distortions in the spectrum. As the additional effect, regardless of the size of the extension, the sensitivity of the enlarged μIMZI was improved by 32%.
关键词： Fiber optics sensors,Laser materials processing,Interferometry,Microcavities,Microstructure fabrication
更新于2025-11-28 14:23:57
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Passively Q-switched fiber laser utilizing new hafnium–bismuth–erbium co-doped fiber as saturable absorber
摘要： A stable all-fiber passively Q-switched erbium-doped fiber laser emitting at 1559 nm is proposed and demonstrated using an 8-cm-long hafnium–bismuth–erbium co-doped fiber (HBEDF) as a saturable absorber (SA). The HBEDF is fabricated in-house and has a linear absorption of around 5.2 dB at the laser operating wavelength of 1559 nm. The Q-switching pulses are obtained with an input pump power ranging from 50 to 121 mW. It has the pulse repetition rate of 81.57 kHz, the shortest pulse width of 3.31 ls, output power of 10 mW, pulse energy of 123 nJ and peak power of 37.3 mW at the maximum pump power of 121 mW. The corresponding signal-to-noise ratio of the electrical spectrum is measured to be around 70 dB, which indicates the stability of the laser. To the best of our knowledge, this is the first demonstration of the deployment of HBEDF SA in generating a robust and steady pulsed laser in 1.5-micron region.
关键词： Fiber saturable absorber,Q-switcher,Fiber laser
更新于2025-11-28 14:23:57
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Study on a high-temperature optical fiber F–P acceleration sensing system based on MEMS
摘要： Vibration measurement at high temperature is of great signi?cance to monitoring the operation of major projects and mechanical equipment. As the temperature resistance of electrical vibration sensors is usually below 600 °C, it cannot meet the requirements of some high-temperature measuring conditions. This paper studies a high-temperature Fabry–Perot (F–P) acceleration sensing system with general single-mode ?ber. A high-temperature sensitive diaphragm is machined based on micro-electromechanical system (MEMS) technology and it is combined with the ?ber microstructure to enable the sensing probe to be packaged under high temperatures. According to the temperature characteristic of the length of the F–P cavity, a signal demodulation system was proposed based on the rapid automatic tracking of the quiescent operation point. The complete optical ?ber F–P acceleration sensing system conducted real-time vibration detection of high temperature casting in the foundry factory. The experimental result indicates that the optical ?ber high-temperature acceleration sensor showed a better vibration response in the working frequency of 100–1000 Hz and the relative error of the frequency measurement is less than 1.56% under normal temperatures and a high temperature of 800 °C.
关键词： Optical ?ber F–P,High-temperature,Acceleration sensor,Tunable laser source,MEMS
更新于2025-11-28 14:23:57
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Mode-locking in Er-doped fiber laser with reduced graphene oxide on a side-polished fiber as saturable absorber
摘要： In this work, the generation of highly stable mode-locked pulses from a side-polished fiber (SPF) embedded with graphene oxide (rGO) nanoparticles (NPs) is proposed and demonstrated. The rGO NPs are obtained from a graphene oxide solution prepared using Hummer’s technique, before being reduced by a hydrothermal route. The rGO NPs, suspended in the form of a solution, are then drop-casted onto the SPF. The SPF is fabricated by polishing away the cladding layer of a single-mode fiber section, leaving the core exposed and allowing the evanescent field of the signal propagating through the fiber to interact directly with the NPs. The SPF is integrated into an erbium doped fiber laser (EDFL) cavity, and the strong nonlinear optical response and spectral filtering by the rGO NPs as well as total anomalous dispersion of the laser cavity generates highly stable soliton mode-locked pulses with visible Kelly’s sidebands at 1544.02 nm. The output pulses have a pulse repetition rate of 16.79 MHz and pulse duration of 1.17 ps throughout the mode-locking operation range of 64.44–280.5 mW. The rGO NP coated SPF in this work demonstrates the viability and performance of the SPF for mode-locked pulse generation via evanescent field interactions.
关键词： Side polished fiber,Reduced graphene oxide,Mode-locked fiber laser,Saturable absorber
更新于2025-11-28 14:23:57
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Mid infrared gas spectroscopy using efficient fiber laser driven photonic chip-based supercontinuum
摘要： Directly accessing the middle infrared, the molecular functional group spectral region, via supercontinuum generation processes based on turn-key fiber lasers offers the undeniable advantage of simplicity and robustness. Recently, the assessment of the coherence of the mid-IR dispersive wave in silicon nitride (Si3N4) waveguides, pumped at telecom wavelength, established an important first step towards mid-IR frequency comb generation based on such compact systems. Yet, the spectral reach and efficiency still fall short for practical implementation. Here, we experimentally demonstrate that large cross-section Si3N4 waveguides pumped with 2 μm fs-fiber laser can reach the important spectroscopic spectral region in the 3–4 μm range, with up to 35% power conversion and milliwatt-level output powers. As a proof of principle, we use this source for detection of C2H2 by absorption spectroscopy. Such result makes these sources suitable candidate for compact, chip-integrated spectroscopic and sensing applications.
关键词： mid infrared,photonic chip,gas spectroscopy,supercontinuum generation,fiber laser
更新于2025-11-28 14:23:57
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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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All-fiber polarization interference filter based uniform multiwavelength erbium-doped fiber laser
摘要： We demonstrate a compact and stable room-temperature multiwavelength erbium doped fiber laser by employing 45° tilted fiber gratings based on an all-fiber polarization interference filter. Benefiting from the filter, the channel number, linewidth, uniformity and stabilization of the multiwavelength laser are greatly improved. The filter also works as a functional polarizing device in a nonlinear polarization rotation, leading to the multiwavelength operation. Instead of a highly nonlinear fiber, the single mode fiber is used to provide enough linearity and to reduce the splice loss. More than 80 wavelengths (within a 3 dB bandwidth), lasing with a linewidth of 0.03 nm and a signal-to-noise ratio of 33 dB, are obtained. The wavelength spacing of 0.164 nm agrees with the channel spacing of the filter, and can be flexibly controlled by adjusting the length of the filter.
关键词： 45° tilted fiber gratings,multiwavelength fiber laser,all-fiber polarization interference filter (AFPIF)
更新于2025-11-28 14:23:57
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Multi-wavelength oscillating and transverse mode switching in an all few-mode fiber laser based on polarization manipulation
摘要： We have proved the polarization dependence of the fiber Bragg grating (FBG), and demonstrated an all few-mode fiber laser that can realize multi-wavelength oscillation and switchable transverse modes simultaneously based on the polarization dependence of FBG. In this fiber laser, single-, dual- and triple-wavelength oscillation can be realized by merely adjusting the polarization controller inside the cavity. Three output transverse modes including fundamental mode, second-order mode, and hybrid modes can be switched as the laser operates at three different single-wavelengths correspondingly. In addition, azimuthally and radially polarized beams can be easily generated. This all few-mode fiber laser scheme may play a more significant role in wavelength division multiplexed (WDM) systems, mode division multiplexed (MDM) systems, sensing, and so on.
关键词： Polarization dependence,Multi-wavelength,Transverse mode,Fiber laser
更新于2025-11-28 14:23:57
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Tungsten disulfide saturable absorber for passively Q-Switched YVO4/Nd:YVO4/YVO4 laser at 1342.2 nm
摘要： By using both tungsten disul?de saturable absorber (WS2-SA) and YVO4/Nd:YVO4(0.3 at.%)/YVO4 crystal, a passively Q-switched laser centered at 1342.2 nm is ?rst reported. Stable Q-switched pulses can be obtained. At the pump power of 12 W, a shortest pulse width of 550 ns and a pulse repetition rate of 97 kHz can be observed by a digital oscilloscope, corresponding to maximum pulse energy of 5.55 μJ and pulse peak power of 10.1 W. The results promote the promising applications of WS2-SA in all-solid-state laser at 1.3 μm.
关键词： WS2 saturable absorber,Diode-pumped lasers,Q-switched lasers,1342.2 nm laser
更新于2025-11-28 14:23:57
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Narrow-line InGaN/GaN green laser diode with high-order distributed-feedback surface grating
摘要： We demonstrate narrow-line green laser emission at 513.85 nm with a linewidth of 31 pm and side-mode suppression ratio of 36.9 dB, operating under continuous-wave injection at room temperature. A high-order (40th) distributed-feedback surface grating fabricated on multimode InGaN-based green laser diodes via a focused ion beam produces resolution-limited, single-mode lasing with an optical power of 14 mW, lasing threshold of 7.27 kA cm?2, and maximum slope efficiency of 0.32 W A?1. Our realization of narrow-line green laser diodes opens a pathway toward efficient optical communications, sensing, and atomic clocks.
关键词： InGaN/GaN,green laser diode,distributed-feedback,narrow-line,surface grating
更新于2025-11-28 14:23:57