A novel orthogonal grating has been proposed and demonstrated. The grating is inscribed over inner cladding of a multi-cladding fiber containing two orthogonally cascaded “cladding” fiber Bragg gratings. Femtosecond laser side-illumination technique is utilized to ensure the two grating inscriptions are precisely positioned and compact in size. With such configuration, two pairs of well-defined cladding resonances have been achieved in reflection, which are originated from the internal cladding (two weakened resonances at shorter wavelength side) and from the fiber core (two stronger resonances at longer wavelength side), respectively. Most importantly, the “cladding” resonances are strongly directional sensitive to the small-vibration.

Date Published: 23 April 2017
PDF: 4 pages
Proc. SPIE 10323, 25th International Conference on Optical Fiber Sensors, 103235T (23 April 2017); doi: 10.1117/12.2262395

Published in SPIE Proceedings Vol. 10323:
25th International Conference on Optical Fiber Sensors
Youngjoo Chung; Wei Jin; Byoungho Lee; John Canning; Kentaro Nakamura; Libo Yuan, Editor(s)