Fresnel Reflection Reduction of Standard Single Mode Fiber End Surfaces via FS Laser Induced Surface Structuring

The use of optical fibers has become indispensable. However, for many applications an important aspect is the suppression of Fresnel reflection losses at the fiber end surfaces, as they cause not only losses, but can cause also interfering signals. One approach to overcome this is surface micro structuring, which leads to a gradual decrease of the average refractive index from the material to the surrounding, suppressing the Fresnel reflection [1]. A convenient option for this is the usage of femtosecond lasers for the generation of laser induced surface structures (LIPSS) [4]. This has successfully been shown among others for fused silica bulk materials [5] and polycrystalline infrared fibers [6], but not for standard single mode fused silica fibers.