This is a small test project I made to test how I could simulate a pulse light through a tube. I used Blender (2.64) and Cycles and basically created a glass tube with an emitting sphere inside with some composited glow effect (with blur nodes), but not too much as the render already gyve significant glow through the glass. The resolution and samples are low, so the quality could be increased significantly with more samples (and possibly calculating it without caustics). As this is a test only, I did not put too much effort into the lighting of the scene.
I generated a small test movie hosted on vimeo for review.