We demonstrate a large improvement in the efficiency of the method proposed by Krug et al. [Opt. Lett. 20, 1767 (1995)] to measure the amplitude of the refractive-index modulation along a fiber Bragg grating. The basic idea consists of using what to our knowledge is a new modulation scheme for the probe beam that not only allows the user to get a better discrimination of the probe light incoherently scattered by the fiber from that scattered by the grating but also facilitates alignment of the setup.
© 2001 Optical Society of America
Original Manuscript: January 11, 2001
Revised Manuscript: June 6, 2001
Published: December 1, 2001
David Ramecourt, Pascal Bernage, Pierre Niay, Marc Douay, and Isabelle Riant, "Improvement in the measurement of index modulation along an optical fiber grating by movement of the probe spot perpendicularly to the fiber axis," Appl. Opt. 40, 6166-6169 (2001)