Aluminum oxide/polydimethylsiloxane-based Q-switched mode-locked erbium-doped fiber laser

A Q-switched mode-locked (QSML) erbium-doped fiber laser integrating aluminum oxide saturable absorber (Al2O3-SA) is demonstrated. With the help of polydimethylsiloxane polymer, Al2O3 powder was securely transferred on a tapered fiber surface and functioned as SA. A QSML pulse sequence was realized at a central wavelength of 1567.4 nm from 80 to 320 mW pump power with its envelope repetition rate ranging from 30.59 to 77.46 kHz. The short duration of 2.54 µs Q-switched envelope comprised of 8.3 ns ML pulses with 252 nJ pulse energy was realized at the maximum pump power of 320 mW. The high damage threshold of Al2O3-SA of beyond 7 GW/cm2 contributes to the future exploration of bulk metal oxide for high-energy optical pulse generation in near-infrared wavelengths

Optimization process of spin-coated black phosphorus/polydimethylsiloxane composite on microfiber as saturable absorber for ultrafast photonics

Numerous saturable absorber (SA) fabrication methods have been proposed and employed in the development of ultrafast laser systems, particularly for microfiber-based SAs decorated with various 2D materials. However, the study on microfiber-SA with different transition lengths is still inadequate. This paper focuses on the design and fabrication method of black phosphorus/polydimethylsiloxane composite microfiber-based SA for ultrashort pulse generation. With optimized microfiber-SA dimensions of 30 mm (up/down taper), 1 mm (waist length) and 10 µm (waist diameter), black phosphorus/polydimethylsiloxane composite was spin-coated on the microfiber at 4000 rpm for 6 min. The integration of the microfiber-SA in an erbium-doped fiber laser exhibited pulse duration of 724 fs at center wavelength of 1560.18 nm. This work provides a guideline for the design of microfiber-based SA using spin-coating technique to maximize its laser performances