A mechanical criterion for the design of readily cleavable microstructured optical fibers

Abstract

Some complex microstructured fibers (MSFs) are well known to produce poor-quality cleaves or even to break at cleavage. But to find widespread use in photonics technology, MSFs will have to be easily cleavable using mechanical cleavers, since more sophisticated techniques add complexity. In this paper, the very different, yet reproducible cleavage patterns of three high air-fraction, double-clad microstructured fibers are analyzed. Fracture faces reveal the fracture propagation paths and provide measurements of the fracture lengths in the intercapillary bridges. These lengths prove to be always shorter than the critical fracture length predicted by fracture mechanics. A criterion based on critical fracture length is thus proposed to design cleavage-robust MSFs.

Hollow-core photonic bandgap fibers: technology and applications

“…Due to their low thermal mass and large surface to volume ratio, the microstructured cladding readily deforms under excessive heat during splicing and thus the guidance properties may be significantly affected and large losses ensue if appropriate precautions are not adopted. Similarly, care has to be taken to obtain good quality fibre terminations when using cleaving tools, as the microstructure disturbs the propagation of the fracture shockwave, which can result in additional defects forming at the hole boundaries [73]. Fortunately, the latest generation of mechanical cleavers incorporating fine tension control allow the realisation of consistently good cleaves, with typical cleave angles of 0.5ᵒ or less, as required for low-loss splicing [74].…”