Low threshold mid-infrared supercontinuum generation in GaAs_0.51Sb_0.49/InP waveguides

Chip-scale broadband light sources in the mid-infrared spectral range are highly desirable for the development of compact spectroscopy and sensing instrumentation in the molecular fingerprint region. Recently, generation of subpicosecond pulses with over 5 W of peak optical power was demonstrated from mode-locked mid-infrared quantum cascade lasers. Monolithic integration of these lasers with a waveguide for supercontinuum generation may dramatically broaden the emission spectrum of these devices. Here we report mid-infrared supercontinuum generation in GaAs_0.51Sb_0.49/InP dielectric waveguides with, to our knowledge, a record-low peak pump power of only approximately 6 W for a pump wavelength of 5 µm, which is required to double the spectral bandwidth of the pump pulse. This pump power level is more than an order of magnitude lower than the current state of the art. Our results pave the way towards the development of an electrically pumped chip-scale mid-infrared supercontinuum source based on a monolithic integration of a quantum cascade laser pump with passive waveguides on an InP platform.