Laser angioplasty has been proposed as a less invasive alternative to bypass surgery for the treatment of occlusive vascular disease in the coronary and peripheral circulation. A major limitation of most laser angioplasty systems has been the inability to create a new lumen, which is larger than the diameter of the laser catheter. The principal reason for this shortcoming has been the fact that most laser angioplasty catheters, yet developed, have projected the laser energy from the distal tip of the catheter, parallel to the central axis of the catheter. This approach works well for the removal of plaque directly in front of the distal tip of the catheter, but it not very effective for debulking eccentric stenoses or lesions larger than the catheter diameter. To address this limitation, we decided to develop a laser angioplasty catheter from which the laser energy exits from the side of the catheter, instead of the tip. The critical element in a lateral-aiming laser catheter is an optical fiber which will project laser energy perpendicularly to its central axis. The fiber design would have to be mechanically stable, heat resistant, and capable of operating with high power cw and pulsed lasers. Thus, a small-diameter catheter including such an optical fiber may be able to effectively debulk large or eccentric stenoses.