Mid-Infrared-to-Telecom Wavelength Conversion via Four-Wave Mixing in a Silicon Core Fibre

The mid-infrared spectral region is of great interest for many applications in areas such as environmental sensing, free space communications, and medical diagnostics. However, accessing tuneable sources in the mid-infrared can be difficult due to the limited gain media in this region. An alternative approach is to make use of existing high power telecoms band pump lasers and couple them with highly nonlinear waveguides that offer efficient wavelength conversion via processes such as four-wave mixing (FWM) [1]. An advantage of this approach is that the signals can also be converted back to the telecom band where there are excellent diagnostic tools. In this regard, silicon core fibres (SCFs) have recently emerged as a promising platform for FWM processes due to their high damage threshold, strong nonlinear refractive index and extended infrared transmission (1.1 ~ 7 μm) [2]. Moreover, as they are clad in silica, the SCFs are directly compatible with the fiberized pump sources, opening a route for the development of robust all-fibre systems [3].