I have a portable USB CD/DVD burner. It's the kind that comes out and all the equipment is on the tray(like a laptop drive).

So I left the tray open yesterday, and I turned on my computer with I plugged in, and I noticed that this lens(LED?) lit up red for most of the time the computer was booting and then shut off. Also If I unplug the drive and plug it back in it will light up for a bit. What is it...and LED or a laser? If it is a laser how dangerous was it that I was messing around looking at it, trying to figure out what it was(while on). I've attached a picture with said device circled.

 

Looks like the sensor that tells the player a disk has been inserted.

 

That is just a sensor used to detect if a disc is in the drive or not, it is most likely just a visible red LED and a phototransistor pair....