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Investigation of narrow band random fiber ring laser based on random phase-shift Bragg grating
摘要： A random ?ber laser based on a 25 mm long random phase-shift ?ber Bragg grating with a ring cavity is experimentally demonstrated in this paper. The random phase-shift grating is fabricated with the beam-scanning method in a single-mode ?ber. The random feedback and light localization are achieved by introducing 20 phase-shift points with random amplitudes along the grating length. A narrow band single-wavelength random ?ber laser with the 3 dB bandwidth of 0.44 pm is realized with a 980 nm laser pumping at 130 mW. The optical signal-to-noise ratio up to 55 dB is obtained at the same pump power. The pump threshold is only 21.8 mW. The number of emitted wavelengths is changeable by adjusting the pump power. The lasing wavelength near 1549.96 nm presents a maximum ?uctuation range of only 1.1 pm over time. With the random grating exposed to water, the mode competition is suppressed and the laser can be operated at more stable single-wavelength mode.
关键词： Laser mode,Ring cavity,Grating,Optical ?ber laser
更新于2025-11-28 14:24:03
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Newly developed chromium-doped fiber as a saturable absorber at 1.55- and 2.0-μm regions for Q-switching pulses generation
摘要： We demonstrate a Q-switching operation laser at 1.55- and 2-μm region using a homemade 10 cm long of Chromium-doped ?ber (CrDF) as a passive saturable absorber (SA). Erbium-doped ?ber (EDF) and Thulium-doped ?ber (TDF) as a gain medium cooperate in the all-?ber ring cavity con?guration. CrDF was fabricated by Modi?ed Chemical Vapour Deposition (MCVD) technique in conjunction with conventional solution doping (SD) method. The CrDF has a saturable absorption of 9% at 1.55-μm region with a saturation intensity of 22 MW/cm2. Therefore, a stable pulse train obtainable within 75–173 mW, with a repetition rate increases from 68.12 kHz to 115.9 kHz. At the maximum pump level, a shorter pulse width, maximum output power, and maximum pulse energy are 3.85 μs, 10.86 mW, and 94.1 nJ, respectively. In TDF laser cavity, the laser pulsing generates from 363 mW to 528 mW, where the repetition rate increases from 13.02 kHz to 27.62 kHz. At maximum pump power, a shorter pulse width, maximum output power, and pulse energy are obtained with 4.48 μs, 6.36 mW, and 230.27 nJ, respectively. Both pulse trains at 1.55- and 2-μm region are stable with a signal-to-noise ratio (SNR) of 71 dB and 44 dB, respectively. These ?ndings are important to the discovery of robust passive saturable absorber development in a form of ?ber which has a similar melting point to the rest of the silica ?ber in the proposed cavities. Thus, it will be a kick-started to alternative form of passive SAs in developing a future high-power ?ber lasers.
关键词： Pulse laser,Ring cavity,Chromium-doped ?ber saturable absorber,Fiber laser
更新于2025-09-23 15:22:29
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ZnS Nanospheres for Optical Modulator in an Erbiuma??Doped Fiber Laser
摘要： Zinc sulfide (ZnS), which belongs to transition metal monochalcogenides, is a semiconductor material with wide direct band gap. It can potentially show some special applications (such as luminescence, phosphor, sensors, infrared window materials, photocatalysis) by changing the morphology, size, and crystal structure of semiconductor materials. However, ZnS nanospheres have not been studied as optical modulators until now. Herein, ZnS nanospheres are synthesized by the hydrothermal method and are used to realize optical modulators in an Er-doped fiber laser. The evanescent field effect is utilized to incorporate the ZnS nanospheres on a tapered fiber. Furthermore, with the increase in pump power, the modulation interval gradually decreases to a minimum of 34.36 ns corresponding to the modulation frequency of 29.1 MHz, which is the highest modulation frequency to our knowledge in a ring cavity all-fiber laser. These results demonstrate ZnS nanospheres together with the interaction of dispersion and nonlinearity in optical fibers can modulate the proposed lasers. This not only provides a new method for controlling the power and frequency of all optical modulators, but also marks an important step for ZnS materials in optics research and device applications.
关键词： optical modulators,nonlinear optical materials,ring cavity fiber lasers
更新于2025-09-19 17:13:59
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m thulium fiber laser with all-fiber ring cavity
摘要： A 1.7-μm thulium-doped all-fiber laser based on a ring-cavity configuration is demonstrated. The long-wavelength lasing near the 1.9-μm thulium emission peak was suppressed using a wavelength division multiplexer and single-mode–multimode–single-mode (SMS) fiber device, both of which served as a short-pass filter instead of the grating devices usually used in 1.7-μm thulium fiber lasers. A stable hundred-milliwatt-level 1720-nm laser output with a narrow spectral linewidth on the order of gigahertz was obtained after the optimization of the output coupling, active fiber length, and SMS device. With a cascaded SMS filter, the output power was further scaled to 227 mW under a launched 1570-nm pump power of 2.8 W, while the slope efficiency was 10.3%. The wavelength coverage could be further extended by using different SMS devices and applying tension on them.
关键词： short-pass filter,1.7 μm,ring cavity
更新于2025-09-16 10:30:52
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Optical Solitons and Stability Analysis in Ring-Cavity Fiber System with Carbon Nanotube as Saturable Absorber
摘要： This paper addresses the ring-cavity ?ber laser system. A class of gray and black soliton solutions of the model are reported by adopting an appropriate envelope ansatz. Further more, the modulation instability (MI) of the equation is studied using the linear-stability analysis (LSA) technique and the MI gain spectrum is derived. Some physical interpretations and analysis of the results obtained are also presented.
关键词： linear stability analysis,ring-cavity ?ber laser system,optical solitons,complex envelope ansatz solution
更新于2025-09-09 09:28:46