High-power mid-infrared supercontinuum laser source using fluorotellurite fiber

High power mid-infrared supercontinuum (SC) laser sources are important for a wide range of applications in sensing, spectroscopy, imaging, defense, and security. Despite recent advances on high power mid-infrared SC laser sources using fluoride fibers, the lack of mid-infrared fibers with good chemical and thermal stability remains a significant technological challenge. Here we show that all solid fluorotellurite fibers we developed can be used as the nonlinear media for constructing 10-W-level mid-infrared SC laser sources. All solid fluorotellurite fibers are fabricated by using a rod-in-tube method. The core and cladding materials are TeO2-BaF2-Y2O3 and TeO2 modified fluoroaluminate glasses with good water resistance and high transition temperature (∼424°C). By using a 60 cm long fluorotellurite fiber with a core diameter of 6.8 μm as the nonlinear medium and a high power 1980 nm femtosecond fiber laser as the pump source, we obtain 10.4 W SC generation from 947 to 3934 nm in the fiber for a pump power of ∼15.9  W, and the corresponding optical-to-optical conversion efficiency is about 65%. The spectral broadening is caused by self-phase modulation, soliton fission, soliton self-frequency shift, and dispersive wave generation. Our results show that all solid fluorotellurite fiber can be used for constructing high power mid-infrared SC laser sources for real applications.