Chris, can you mention the name and model of the laser system you are using?

It is possible the bundled software has the ability to generate tangent arcs from the splines within some user defined tolerance. In that case saving as a spline would be better than saving as a polyline.

The setting for the conversion may not be entirely obvious. I've worked for a few CNC manufacturers, including lasers, and sometime the software included with the machine has the functionality spread over several applications rather than being conveniently integrated.