Generation of a continuum extending to the midinfrared by pumping ZBLAN fiber with an ultrafast 1550-nm source

Pulses from a commercial erbium-doped fiber laser are coupled into a standard silica fiber and a standard fluoride fiber connected in series. By cascaded Raman soliton self-shifting, a continuum extending to a wavelength of similar to 3 mu m is generated. The total average power emitted in the 1.8-3.4-mu m range is 5 mW. Throughout the 1.4-2.9-mu m range, the average spectral power is similar to 4 mu W/nm and higher, corresponding at 2.9 mu m to a spectral radiance approximately 4600 times that of a 3000 K blackbody.