An endovascular laser treatment device preferably includes a catheter having a hub at its proximal end, an optical fiber for insertion into the catheter, a fiber connector attached to the optical fiber at a selected distance from the distal end of the optical fiber, and a temporary stop removably mounted around the optical fiber. The treatment device has two positions: a protective position and an operating position. As the fiber is inserted through the catheter, the temporary stop rests against the hub and places the fiber tip in the protective position where the distal end of the optical fiber is positioned near the distal end of the catheter, but is still disposed inside the catheter. When the temporary stop is removed and the fiber connector is coupled with the catheter hub, the fiber tip is in the operating position where the distal end of the optical fiber extends past the distal end of the catheter by a predetermined distance to expose the fiber tip.