Reduction of Intensity Noise in Hollow Core Optical Fiber Using Angle-Cleaved Splices

Abstract

When spliced to solid core optical fiber, a hollow core optical fiber (HCF) exhibits multipath interference. Reflections at the air/glass interfaces add coherently in transmission, producing intensity fluctuations. This can lead to excess intensity noise at the output of a fiber segment. In this letter, angle-cleaved splices were performed on HCFs to reduce this noise without significant alteration of the fiber’s optical properties. Cleave angles ranging from 7° to 12° produced splices with return losses less than −50 dB and excess insertion losses typically around 1 or 2 dB. A 37-dB reduction in intensity noise over a flat-cleaved splice was achieved with negligible increase in higher order mode generation or polarization-dependent loss.