13 research outputs found

    Generation of microsecond ytterbium-doped fibre laser pulses using bismuth telluride thin film as saturable absorber

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    Bismuth telluride (Bi2Te3), a type of topological insulators, is currently in hot pursuit due to its unique physical properties. Therefore, this paper describes a simple Q-switched Ytterbium-doped fiber laser (YDFL) by using Bi2Te3 thin-film as saturable absorber. The few layers Bi2Te3 film was fabricated using optical deposition technique and subsequently, was used in an all-fiber, YDFL setup. As a result, a self-starting Q-switching pulses were first occurred when the laser pumping power reached 88.6 mW. As the pump power level increased, the observed pulses repetition rates had increased steadily from 17 to 29.63 kHz. Hence, this work demonstrated that Bi2Te3 thin-film can be used to successfully generate Q-switching pulses at 1-micron region and is well suited for many photonic applications operated at this wavelength region

    Experimental study of dual-wavelength laser generation in Ytterbium-doped fiber / Muhammad Aizi Mat Salim

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    This thesis describes the research work that has been carried out on generating dual-wavelength fiber lasers (DWFLs) in the one micron waveband-based ytterbium-doped fiber as an active medium. Various devices were used, including dual-tapered microfiber-based Mach-Zehnder Interferometer (MZI), Side Polished Fiber (SPF), and strain technique was discussed in DWFLs operation with regard to stability, tunability, output power and Side Mode Suppression Ratio (SMSR). A stable Single Longitudinal Mode (SLM) DWFL was successfully demonstrated by employing 2 μm diameter of dual-tapered microfiber MZI with SMSR of 50 dB and wavelength spacing of 0.94 nm. Then, by employing dual-tapered microfiber and tunable band pass filter (TBPF) together, the narrowest wavelength spacing of DWFL was obtained with 0.06 nm and SMSR of 50dB. Another dual-tapered microfiber with diameter of 10μm was positioned between xyz-translation stages, and then a strain was applied on the microfiber by tuning the micrometer driver. As a result, stable four sets of DWFLs were obtained at displacements from 2 to 190μm, and these outputs remained consistent after repeated several times. The SPF was also employed into the ring cavity to generate 3 sets of DWFLs with wavelength spacing of 6.89nm, 16.28nm and 22.16nm by adjusting the polarization controller (PC). While in pulse generation of DWFL, both wavelength selective filters and saturable absorbers (SAs) were employed together in the ring cavity to generate dual-wavelength and passively Q-switched operation simultaneously. The wavelength selective filters were dual-tapered microfiber MZI and SPF whereas the saturable absorbers (SAs) used were molybdenum diselenide (MoSe2), black phosphorus (BP), titanium dioxide (TiO2) and zinc oxide (ZnO). The SAs used in our experiments were shown to be new, potentially high quality saturable absorbers. Molybdenum diselenide as SA was used to generate passively Q-switched in DWFL based dual-tapered microfiber MZI. The obtained Q-switched based MoSe2 had a repetition rate ranging from 15.3 to 35.2 kHz. DWFL based microfiber Q-switched using BP as SAs was successfully demonstrated with tunable repetition rate from 6.5 to 62.5 kHz. Likewise, a passively Q-switched dual-wavelength YDFL using a titanium dioxide as SA and SPF as a wavelength selective filter had a repetition rate from 31.2 to 64.5 kHz. Lastly, zinc oxide together with SPF was proven in generating dual-wavelength passively Q-switched with a repetition rate from 67.6 to 104.2 kHz. The tunable repetition rate, output power, pulse energy and pulse width, and have been discussed in Q-switched operation

    Highly stable and tunable narrow-spacing dual-wavelength ytterbium-doped fiber using a microfiber Mach-Zehnder interferometer

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    We describe a successful demonstration of highly stable and narrowly spaced dual-wavelength output via an ytterbium-doped fiber laser. A microfiber-based Mach-Zehnder interferometer and a tunable bandpass filter were both placed into the laser ring cavity for the purpose of ensuring a stable and narrowly spaced dual-wavelength output. Experimental results comprised three sets of dual-wavelength lasing output with wavelength spacing of 0.06, 0.09, and 0.22 nm, respectively, and side-mode suppression ratio of ∼50 dBm. A subsequent stability test provided evidence that maximum power and wavelength fluctuation were less than 0.8 dB and 0.01 nm, respectively, and thus, the obtained output was considered to be highly stable in dual-wavelength operation. The proposed system offers advantages of flexibility in dual-wavelength laser generation in addition to excellent reliability

    Dual wavelength single longitudinal mode Ytterbium-doped fiber laser using a dual-tapered Mach-Zehnder interferometer

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    This paper describes a dual wavelength single longitudinal mode (SLM) demonstration for a proposed ytterbium-doped fiber laser. A dualtapered Mach-Zehnder interferometer (MZI) was inserted into the laser ring cavity setup to ensure a stable dual wavelength and SLM operation. The consequent dual wavelength lasing operation had a wavelength spacing of 0.94 nm and a side mode suppression ratio (SMSR) of 50 dB, with the linewidth of this setup measured as 294.15 kHz. A stability test allowed for a measurement of max power fluctuation as less than 0.8 dB for each wavelength and which was indicative of a stable dual wavelength operation

    Tunable dual-wavelength ytterbium-doped fiber laser using a strain technique on microfiber Mach-Zehnder interferometer

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    In this paper, stable dual-wavelength generation using a strain technique for a ytterbium-doped fiber laser is successfully demonstrated. A microfiber-based Mach-Zehnder interferometer is inserted into the laser ring cavity and stretched using the xyz translation stage. Four sets of dual-wavelength output lasing are obtained when the strain is applied onto a microfiber. The dual-wavelength output possesses spacing between 7.12 and 11.59 nm, with displacement from 2 to 190 μm from the central wavelength. The obtained side-mode suppression ratio is ∼48 dBm, while the maximum power fluctuation and wavelength shift are less than 0.6 dB and 0.01 nm, respectively. The results demonstrate that this setup generates a stable dual-wavelength laser in the 1 μm region

    Influence of Internal Stresses in Few-Mode Fiber on the Thermal Characteristics of Regenerated Gratings

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    Abstract The pre-treatment of few-mode fibers (FMFs) has been successfully done with CO2 laser. The wavelength difference, Δλ between the two resonant wavelengths in the few-mode fiber Bragg grating (FMFBG) varies with temperature increment during the annealing process. The results show that the treated fibers with lower stresses have lower thermal sensitivity in Δλ than that of non-treated fiber. However, the treated fibers produce FMFBGs with better thermal durability and regeneration ratio. It is conceived that the presence of those stresses in the pristine fiber is responsible for the high thermal sensitivity in Δλ. The thermal relaxation of stresses and structural rearrangement during the thermal annealing process are responsible for the degradation of the strength and resilience of the regenerated grating

    Generation of dual-wavelength ytterbium-doped fibre laser using a highly nonlinear fibre

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    This paper describes the dual-wavelength operation in the 1060 nm region by applying an ytterbium-doped gain medium fiber and a highly nonlinear fiber (HNLF) as the wavelength selective filter. Due to its nonlinear properties and birefringence co-efficient, the HNLF also functions as a stabilizer for dual-wavelength fiber laser operation. Results from the experiment show that the fluctuated power of the system is less than 0.6 dB when continuously run for 20 min, indicating the system's stability. The spacing of the dual-wavelength output is obtained by fine-tuning the polarization controller within the fiber ring laser setup. The spacing ranges between 2.7 nm-21.05 nm

    Generation of Microsecond Ytterbium-Doped Fiber Laser Pulses using Bismuth Telluride Thin Film as Saturable Absorber

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    Bismuth telluride (Bi2Te3), a type of topological insulators, is currently in hot pursuit due to its unique physical properties. Therefore, this paper describes a simple Q-switched Ytterbium-doped fiber laser (YDFL) by using Bi2Te3 thin-film as saturable absorber. The few layers Bi2Te3 film was fabricated using optical deposition technique and subsequently, was used in an all-fiber, YDFL setup. As a result, a self-starting Q-switching pulses were first occurred when the laser pumping power reached 88.6 mW. As the pump power level increased, the observed pulses repetition rates had increased steadily from 17 to 29.63 kHz. Hence, this work demonstrated that Bi2Te3 thin-film can be used to successfully generate Q-switching pulses at 1-micron region and is well suited for many photonic applications operated at this wavelength region. © 2019 Penerbit Universiti Kebangsaan Malaysia. All rights reserved
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