In recent years, optical fibers with smaller cladding diameters—such as 40 µm, 50 µm, and 60 µm—have attracted increasing attention in the medical technology sector. Compared with conventional optical fibers with 125 µm cladding, these smaller fibers offer greater flexibility, reduced invasiveness, and better integration into compact medical devices. As minimally invasive medicine continues to grow, small-diameter optical fibers are becoming an important enabling technology.

One of the most common applications is laser lithotripsy in urology. In procedures used to treat kidney stones, doctors insert a flexible endoscope through the urinary tract and deliver laser energy through a thin optical fiber to break stones into small fragments. Lasers such as the Holmium:YAG Laser and the Thulium Fiber Laser rely on optical fibers to deliver energy precisely. Smaller fibers allow the endoscope to maintain better flexibility and enable surgeons to reach stones located in narrower or more complex anatomical pathways.

Another important application is the treatment of vascular diseases such as varicose veins. A minimally invasive technique known as Endovenous Laser Ablation uses an optical fiber inserted into the affected vein. Laser energy heats the vessel wall, causing it to close and eventually be absorbed by the body. Thin optical fibers help reduce trauma during insertion and allow physicians to navigate small blood vessels more easily.

Small-diameter optical fibers are also used in advanced neurological procedures. In techniques like Laser Interstitial Thermal Therapy, a very thin laser probe is inserted into brain tissue to precisely destroy tumors or abnormal tissue. Because brain structures are extremely delicate, smaller fibers are preferred as they minimize damage to surrounding tissue while providing accurate energy delivery.

In oncology, optical fibers play a key role in light-based treatments such as Photodynamic Therapy. In this therapy, a photosensitive drug accumulates in cancer cells and is then activated by light delivered through an optical fiber. The resulting reaction destroys targeted cells while sparing healthy tissue. Small optical fibers make it easier to deliver light through endoscopes into organs such as the lungs, esophagus, or bladder.

Looking ahead, the demand for small-cladding optical fibers is expected to grow alongside the development of minimally invasive surgery, robotic surgery systems, and advanced endoscopic instruments. As medical devices continue to become smaller and more precise, the need for flexible, high-performance optical fibers will increase. Although this market is smaller than the telecommunications fiber industry, it is characterized by high technical requirements and strong value per unit, making it an important niche within the broader optical fiber ecosystem.

In summary, small-diameter optical fibers are enabling new possibilities in modern medicine—from kidney stone treatment to cancer therapy. As healthcare technology advances toward less invasive and more precise procedures, these specialized fibers will play an increasingly critical role in future medical innovations.