An optical fiber endcap device may include an input facet spliced onto an input fiber and an output end through which counterpropagating light enters the optical fiber endcap device. The optical fiber endcap device further includes a plurality of angled facets that are arranged at respective angles relative to an axis of the optical fiber endcap device to reflect at least a portion of the counterpropagating light back through the output end of the optical fiber endcap device.