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过滤筛选
- 2019
- higher- order modes
- few-mode regime
- on-board cable systems
- mode coupling
- laser-based multi-Gigabit data transmission
- large core multimode optical fiber
- industrial networks
- differential mode delay
- Optoelectronic Information Science and Engineering
- Povolzhskiy State University of Telecommunications and Informatics (PSUTI)
- Malaviya National Institute of Technology Jaipur
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Ultrafast soliton and stretched-pulse switchable mode-locked fiber laser with hybrid structure of multimode fiber based saturable absorber
摘要： We demonstrate an all-fiber mode locked laser based on hybrid structure of multimode fiber saturable absorber (SA) that can realize both conventional soliton and stretched-pulse states. Stable 16.44 MHz conventional soliton pulses are achieved by injecting 80 mW threshold pump power. By increasing the incident pump power to 420 mW, the laser evolves from soliton operation into stretched-pulse mode locking state. 310 fs stretched-pulse are obtained with the same repetition rate as the soliton pulses. The center wavelength and its 3 dB spectrum bandwidth are 1603 nm and 14.2 nm, respectively. For the first time, we experimentally confirm transition between conventional soliton and stretched-pulse in 1.5 μm mode-locked fiber laser by introducing multimode optical fiber SA. Moreover, the maximum single pulse energy of nearly 1 nJ is achieved. Such all-fiber mode-locked lasers based on hybrid structure of multimode fiber are attractive for practical applications without damage and the limitation of life time.
关键词： hybrid structure,mode-locked fiber laser,multimode fiber,saturable absorber,Ultrafast soliton,stretched-pulse
更新于2025-11-28 14:24:03
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Lorentzian demodulation algorithm for multimode polymer optical fiber Bragg gratings
摘要： For strain sensing applications, we develop a simple and accurate Lorentzian demodulation algorithm for fiber Bragg gratings (FBGs) inscribed in multimode optical fibers. As multimode FBG spectra generally exhibit multiple peaks, simply tracking some particular spectral peaks (i.e., maximum detection) results in measurement failure when the strain is large. Here, using an FBG inscribed in a perfluorinated graded-index multimode polymer optical fiber, we experimentally evaluate the new method by comparing its performance with those of other demodulation algorithms, such as the maximum and centroid detection methods. Finally, using this method, we demonstrate the accurate measurement of strain of up to 1.0%.
关键词： fiber Bragg gratings,FBG,Lorentzian demodulation algorithm,strain sensing,multimode polymer optical fiber Bragg gratings
更新于2025-11-28 14:24:03
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Self-starting mode-locked Tm-doped fiber laser using a hybrid structure of no core - graded index multimode fiber as the saturable absorber
摘要： We experimentally demonstrated a passively mode-locked all-fiber Tm laser using a no-core-graded-index multimode fiber structure as a saturable absorber based on the nonlinear multimode interference. Stable fundamentally mode-locking operation was obtained at a pump threshold of 180 mW. The output soliton pulses had a centre wavelength, spectral width, pulse duration, and repetition rate of 1895.7 nm, 3.3 nm, 1.25 ps, and 18.91 MHz, respectively. This is a simple, low-cost, stable, and convenient laser oscillator, with many potential applications in eye-safe ultrafast photonics.
关键词： Nonlinear multimode interference,Fiber laser,Mode-locked laser
更新于2025-11-28 14:24:03
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Passively Q-Switched All-Fiber Yb-Doped Lasers Based on Nonlinear Multimode Interference?
摘要： We report a passively Q-switched all-?ber Yb-doped laser using the structure of step-index multimode ?ber and graded-index ?ber (SIMF-GIMF) as a new saturable absorber (SA) based on the nonlinear multimode interference (NL-MMI). Through bending the SA to a certain state, we obtain a stable Q-switched laser operation with the shortest pulse duration of 4.37 μs and a corresponding repetition rate of 147.6 kHz with center at 1,039 nm. The maximum average output power and single pulse energy are recorded to be 2.409 mW and 16.3 nJ, respectively. To the best of our knowledge, this paper con?rms experimentally for the ?rst time Q-switched laser operation based on SIMF-GIMF SA in all-?ber lasers. In addition, we also observed unstable Q-switched mode-locking operation. All-?ber lasers based on SIMF-GIMF SA are attractive for practical applications and undergo no damage and performance degradation with time.
关键词： multimode ?bers,all-?ber Yb-doped lasers,Q-switched operation
更新于2025-11-28 14:24:03
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L-band tunable and dual-wavelength mode locked fiber laser with NCF-GIMF based SA
摘要： A hybrid structure of no-core fiber and graded-index multimode fiber (NCF-GIMF) is demonstrated, which can be used as both the saturable absorber (SA) and the wavelength selective element. By employing such a device, an L-band wavelength tunable Er-doped mode-locked laser is realized and stable single solitons of ~1.7ps, with continuously tunable wavelengths from 1574 nm to 1601.1 nm, are generated. Moreover, dual-wavelength mode-locked laser operation at 1575.4 nm and 1603 nm is achieved, with pulse duration of 1.2 ps and 1.7 ps, respectively. The proposed device is simple and compact, and represents an effective approach for tunable and dual-wavelength mode-locked fiber laser operation.
关键词： Laser tuning,Optical fiber devices,Laser mode locking,Fiber-graded index multimode fiber,Fiber nonlinear optics
更新于2025-11-28 14:23:57
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Large diameter coreless fiber as a saturable absorber for erbium doped fiber laser cavity based on multimode interference
摘要： We demonstrated a Q-switched erbium-doped fiber laser (EDFL) based on large diameter coreless fiber without intra-cavity tuning element for the first time. A single mode fiber –coreless fiber –single mode fiber (SNCFS) structure was employed as a passive Q-switcher relies on Kerr nonlinearity associated with multi-mode interference (MMI) effect. By splicing 10 cm of 125 μm in diameter coreless fiber (NCF) between two single mode fibers (SMFs), C-band Q-switched EDFL with 3-dB bandwidth of 0.138 nm was successfully obtained, making it a simple, compact and easily handling modulation device. A stable Q-switched pulses were achieved with a pump threshold of 188 mW. Pulse repetition rate ranges from 73.3 to 92.0 kHz, minimum pulse width of 3.5 μs and maximum energy of 50.9 nJ were recorded.
关键词： Q-switched,Fiber lasers,Multimode interference
更新于2025-11-28 14:23:57
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Refractive index sensor based on ultrafine tapered single-mode nocladding single-mode fiber structure
摘要： A refractive index (RI) sensor based on a tapered no cladding fiber (NCF) is proposed theoretically and experimentally. The RI sensor is fabricated by splicing a NCF in the middle of two single mode fibers (SMF), and then the NCF is tapered to get lower waist diameter. Due to the lack of cladding, surrounding refractive index (SRI) can directly affect the light propagation of NCF, and the decrease of diameter can further improve the RI sensitivity by strengthening the evanescent field. The sensitivity with different lengths and waist diameters of NCF is investigated. It is observed that there are different linear relationships in different refractive interval and the RI sensitivity increases obviously with the waist diameter decreasing, especially when it is below 30 μm. RI sensitivity of the sensor reaches 686 nm/RIU when the waist diameter is 13 μm and SRI is at the range of 1.333–1.350. The sensor can be widely used in biosensing for its simple operation and high sensitivity at low SRI.
关键词： Refractive index sensor,Multimode interference,No cladding fiber,Tapering
更新于2025-11-28 14:23:57
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Hot wire chemical vapor deposition for silicon photonics: An emerging industrial application opportunity
摘要： In this work different silicon photonic devices, including straight waveguides, multi-mode interference devices and Mach-Zehnder interferometers, were fabricated and characterized on hot-wire chemical vapor deposition (HWCVD) silicon nitride (SiN) layers deposited at temperatures below 350 °C. These layers presented a hydrogen concentration of 13.1%, which is lower than that achieved with plasma enhanced chemical vapor deposition at these deposition temperatures. The lowest reported optical propagation losses of 6.1 dB/cm and 5.7 dB/cm, 1550 nm and 1310 respectively, for straight SiN waveguides prepared by HWCVD was measured. We demonstrated that silicon nitride SiN, prepared using HWCVD, is a viable material for silicon photonics fabrication.
关键词： Multimode interferometer,Silicon photonics waveguides,Silicon photonics,Hot wire chemical vapor deposition,Silicon nitride,Mach-Zehnder interferometer
更新于2025-11-21 11:20:42
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Research on the influence of alignment error on coupling efficiency and beam quality for Gaussian beam to multimode fiber
摘要： The effect of alignment error on the coupling efficiency and beam quality of a Gaussian beam coupled into a large-core multimode fiber is studied in this paper. The equations for evaluating the effect of alignment error on the coupling efficiency are derived separately, and verified with the method of simulation. The calculation and simulation results obtained are highly consistent. In the same way, the effects of alignment error on the beam power distribution are discussed. The results show that the lateral error will change the path of partial light to a large extent, and have a greater influence on the power distribution of the Gaussian beam than the longitudinal error and angular error do.
关键词： Multimode fiber,Coupling efficiency,Beam quality,Alignment error
更新于2025-09-23 15:23:52
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Averaged nonlinear equations for multimode fibers valid in all regimes of random linear coupling
摘要： We develop averaged equations to model nonlinear propagation in multimode fibers that are valid in all regimes of random, linear, intermodal coupling. The propagation equations apply to the three existing regimes of linear coupling – the two previously studied all-mode (strong) and mode-group (weak) couplings and the new intermediate coupling regime. The equations are therefore general and can describe nonlinear propagation for all types of intermodal linear coupling that can exist between modes in a fiber supporting multiple spatial modes. Numerical simulations are performed to validate the new averaged propagation equations in the nonlinear regime.
关键词： Space-division multiplexing,Nonlinear optics,Multimode fibers
更新于2025-09-23 15:23:52