Thulium pumped mid-infrared 09–9μm supercontinuum generation in concatenated fluoride and chalcogenide glass fibers

Abstract

We theoretically demonstrate a novel approach for generating Mid-InfraRed SuperContinuum (MIR SC) by using concatenated fluoride and chalcogenide glass fibers pumped with a standard pulsed Thulium (Tm) laser (T_FWHM=3.5ps, P₀=20kW, ν_R=30MHz, and P_avg=2W). The fluoride fiber SC is generated in 10m of ZBLAN spanning the 0.9–4.1μm SC at the −30dB level. The ZBLAN fiber SC is then coupled into 10cm of As₂Se₃ chalcogenide Microstructured Optical Fiber (MOF) designed to have a zero-dispersion wavelength (λ_ZDW) significantly below the 4.1μm InfraRed (IR) edge of the ZBLAN fiber SC, here 3.55μm. This allows the MIR solitons in the ZBLAN fiber SC to couple into anomalous dispersion in the chalcogenide fiber and further redshift out to the fiber loss edge at around 9μm. The final 0.9–9μm SC covers over 3 octaves in the MIR with around 15mW of power converted into the 6–9μm range.