A novel Mach–Zehnder interferometer based on a fiber multimode interference structure combined with a long-period fiber grating (LPG) is proposed. The multimode interference is achieved through the use of a MMF section spliced between two single-mode fibers, with a length adjusted to couple a fraction of light into the cladding modes. A LPG placed after the MMF couples light back into the fiber core, completing the Mach–Zehnder interferometer. This novel configuration was demonstrated as a bending sensor.
© 2007 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: July 31, 2007
Revised Manuscript: September 24, 2007
Manuscript Accepted: September 26, 2007
Published: October 15, 2007
O. Frazão, J. Viegas, P. Caldas, J. L. Santos, F. M. Araújo, L. A. Ferreira, and F. Farahi, "All-fiber Mach-Zehnder curvature sensor based on multimode interference combined with a long-period grating," Opt. Lett. 32, 3074-3076 (2007)