For optical engineers and medical device procurement managers, specifying the correct parameters for a disposable bare fiber is a balancing act between energy density and mechanical flexibility. Selecting an incorrect fiber core diameter can lead to inefficient tissue ablation or, worse, a blown connector.

Here is a technical breakdown of how to choose the right core size for your SMA905 silica fibers based on your laser application.

Small Cores (200μm to 272μm): High Flexibility for Urology & Dentistry

Small-core fibers are the go-to choice when navigating tight, winding anatomical pathways.

Primary Application: Holmium laser lithotripsy (kidney stones) via flexible ureteroscopes, and intricate dental root canal therapies.

Why it matters: A 200μm core fiber offers an excellent bending radius, allowing the scope to deflect fully without snapping the fiber. However, due to the small surface area, they require precise laser alignment to avoid burning the SMA905 connector entry face.

Medium Cores (365μm to 400μm): The Versatile All-Rounder

Medium-core fibers provide a perfect sweet spot, offering robust power handling while maintaining decent flexibility.

Primary Application: Endovenous Laser Ablation (EVLT) and various ENT (Ear, Nose, and Throat) surgical procedures.

Why it matters: They can safely transmit higher wattages (often up to 30W–50W depending on the laser source) without significant risk of fiber degradation, making them the standard consumable for outpatient vascular clinics.

Large Cores (550μm to 600μm+): Maximum Power for Open Surgery

When raw power delivery and large coagulation zones are required, large-core fibers take the stage.

Primary Application: BPH (prostate enucleation), general surgery tissue cutting, and industrial high-power laser welding/marking.

Why it matters: These fibers can handle massive energy loads with minimal risk of face damage. The trade-off is rigidity—they have a much larger minimum bending radius and are strictly meant for rigid endoscopes or handpieces.

Final Technical Check

Beyond core size, ensure your supplier uses high-purity synthetic fused silica and biocompatible ETFE jackets.