We demonstrate the generation of Q-switched pulses from an ytterbium-doped fiber laser (YDFL) using quantum dot (QD) CdSe as a passive saturable absorber (SA). The CdSe QD is fabricated by the synthesis of CdO, Se, and manganese acetate and paraffin oil and oleic acid as the solvent and surfactant, respectively. The CdSe QD is then doped into poly-methyl-methacrylate (PMMA) via an emulsion polymerization process. A PMMAhosted CdSe QD thin flake with a homogeneous end surface is then formed and placed between two ferrules and assembled in a YDFL cavity to achieve the Q-switching operation with a repetition rate of 24.45 to 40.50 kHz while varying the pump power from 975 to 1196 mW. The pulse width changes from 6.78 to 3.65 μs with a maximum calculated pulse energy at 0.77 μJ at a pump power of 1101 mW. This work may be the first demonstration of CdSe QD-based Q-switching in an all-fiber configuration that should give proportional insight into semiconductor QD materials in photonics applications.
We report an efficient method for generating a 2 micron laser based on an optical parametric oscillator (OPO). It uses a long piece of a newly developed double-clad ytterbium-doped fiber (YDF), which is obtained by doping multi-elements of ZrO 2 , CeO 2 and CaO in a phosphoalumina-silica glass as a gain medium. The efficient 2 micron laser generation is successful due to the presence of partially crystalline Yb-doped ZrO 2 nano-particles that serve as a nonlinear material in a linear cavity configuration and high watt-level pump power. Stable self-wavelength double lasing at 2122 nm with an efficiency of 7.15% is successfully recorded. At a maximum pump power of 4.1 W, the output power is about 201 mW.
Ambulance is one the most critical component in healthcare where it must have highest reliability and mobility to ensure minimum travel time of patient to the hospital. In Malaysia, there are significant number of cases where ambulance tend to have breakdown or caught on fire due to electrical current overload which caused by unmanaged electrical usage by medical equipment. To overcome this problem, a smart power management system has been developed by employing Hall-Effect based current sensor replacing conventional fuse. The sensor reading is actively analysed by a microcontroller which will cut off electrical power from over-current equipment. The system also can prioritize some critical equipment to be powered when there are limited current available.
We have demonstrated a passive Q-switched Thulium-doped fiber laser (TDFL using samarium oxide (Sm2O3) nanomaterial as saturable absorber (SA). The Sm2O3 based SA was fabricated by simply mixing the Sm2O3 powder solution with polyvinyl alcohol (PVA) solution. The homogeneously mixed solution was spread and dry to form a thin film. A piece of 1 mm x 1 mm of the SA thin film is sandwiched between two fiber ferrules and incorporated into a TDFL ring cavity for pulses generation. By controlling the loss and gain in the cavity, stable Q-switching operation was generated. The repetition rate was tunable from 17.62 kHz to 29.20 kHz by varying the pump power from 619 mW to 784 mW. The smallest pulse width of 3.54 µs and the highest pulse energy of 0.20 uJ were obtained at the highest pump power.
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