Yes, I’m quite sure that the tiny amount of electromagnetic energy emitted by your router is not going to adversely affect your dvds.
Light is a form of electromagnetic energy too, and it [B]can[/B] degrade the dyes in dvds that you write to. But it takes direct sunlight, over a fair amount of time to do this.
DVD-Rom disks are what you mentioned in your original post. They are made differently from dvds that you write to. They use a metal layer sandwiched between the polycarbonate plastic instead of a dye layer, and tend to be fairly durable.