High power cladding mode stripper

A novel approach for stripping cladding light from double clad fibers is demonstrated. This is achieved by index matching the cladding of the fiber with a glass capillary collapsed onto the fiber, allowing the cladding modes to expand in a larger volume of the capillary before they are dissipated through a high-index heat sink material into a metal package. We minimize the signal quality degradation by using a lower melting point capillary glass. We demonstrate a device with 100W cladding power removed with 99% (20dB) extinction. Continuous operation for an hour without any power degradation is demonstrated.