Multimode Fiber Trench Structure Bending Loss Reduction

The patent applies local quality by creating a trench structure at a specific location in the cladding layer, rather than modifying the entire fiber profile. The trench is positioned at a radial distance from the core where it can effectively reduce bending losses without significantly complicating the overall fiber structure. This localized modification allows the fiber to maintain simplicity while gaining enhanced bending resistance.

The patent applies parameter changes by optimizing the trench dimensions (width, depth, and radial position) to achieve the minimum effective volume needed for bending loss reduction. By carefully controlling these parameters, the trench provides sufficient bending resistance while minimizing its disruptive effect on signal quality and bandwidth. The trench volume is kept small but strategically positioned to be most effective.

The patent converts the harmful effect of bending (which normally causes signal loss and mode coupling) into a beneficial filtering mechanism. By strategically positioning the trench, bending-induced mode coupling is enhanced to selectively filter out higher-order modes that are more susceptible to bending losses. This transforms the bending effect from a purely harmful phenomenon into a useful mode filtering mechanism that improves signal quality.