High Efficiency Pump-Enhanced Difference Frequency Generation for Mid-IR Communications

We report a compact difference frequency generation (DFG) intracavity structure emitting at 3.43 microns with greater than 100 mW output power. The device consists of a diode-pumped Nd:YVO4 cavity providing the 1064 nm pump light, and a C-band EDFA signal beam coupled into the cavity via a dichroic mirror. The pump and signal are combined in a 50 mm PPLN to generate mid-infrared light via quasi phase matching. The proof of principle prototype was previously published, but we have since improved the total output power and have a more developed prototype ready for professional packaging. We also present the theory and simulation work that led to the improvements and discuss future possible optimizations using insights from the modelling.