We report the experimental results of ultraviolet-extended broadband supercontinuum (SC) generation in a carefully designed uniform seven-core photonic crystal fiber (PCF) pumped by Ti:sapphire femtosecond laser at 800 nm. Three different PCFs of various core diameters are fabricated to achieve group-velocity matching for ultraviolet components. A wide optical spectrum spanning down to 350 nm is obtained, which is the shortest wavelength SC generation in multicore PCF to date. High spectral flatness (10 dB) has been achieved in the entire visible window.
The visible supercontinuum (SC) sources has played an important role in biomedical applications. However, the small core size of photonic crystal fiber (PCF) restrict the development of high power SC by its small mode field area. In addition, the zero dispersion wavelength (ZDW) of the PCF with small core diameter is usually below 1 μm, which is far away from the 1.06 μm laser which is the most commonly used pump source. As the ZDW of PCF shifts away from the pump, the intensity of visible light decreases correspondingly. We promote a new technique to get an enhanced visible SC with high output power, which involves enhanced visible SC generation in a seven-core PCF pumped by a high power 1016 nm fiber laser. Muti-core PCFs offer a possibility of scaling up the mode field area to a large extent without remarkable change in dispersion properties, which show great potential in high power SC generation. Using a 1016 nm fiber laser as the pump makes the pump wavelength closer to the ZDW of PCF, which could raise the intensity of visible light. In this paper, we report an enhanced visible SC generation ranging from 400 nm to 2300 nm in a seven-core PCF pumped by a 1016 nm picosecond fiber laser. The visible light (400~800 nm) occupies 31% of the total SC power 24 W and the power of the visible light is about 7.4 W.
We design a seven-core photonic crystal fiber with specifically designed dispersion and group velocity profile which is optimized for high-power visible supercontinuum (SC) generation pumped by ∼1-μm pulsed lasers. The fiber has both a large air-filling fraction and a large effective mode field area. Additionally, the in-phase supermode of this fiber exhibits an even field distribution after mode modification. The simulation results suggest that it has a great potential to generate a high-power SC extending to 400 nm, which is highly desirable in biological applications.