5.2        Characterization of a Fiber Bragg Grating under Diametric Loading

5.2.2       Experimental Setup

The mechanical setup allows for the application of uniform diametric load on an optical fiber and permits the reproducible rotation of the fiber around its axis. Fig. 5-16 shows the setup without the rotation system. The ball situated between the lever and the upper glass/steel part, ensures the transmission of a uniform force on both fibers from the suspended mass. Two fibers are used to ensure a perfect uniform loading.

Fig. 5-16 : Side and Front view of the setup

The rotation system is based on a fiber magnetic clamp holder (insert of Fig. 5-17). The angle between the diametric load and the fiber is set with the metal handle that follows the angle graduation written on the white half-disk (Fig. 5-17).

Fig. 5-17 : Pictures of the experimental setup for diametric load (insert : rotation system)

The optical setup for Bragg wavelength measurement in transmission is presented in Fig. 5-18. Another configuration in reflection using a 3 dB coupler has also been realized. Using a linearly polarized tunable laser and a polarization controller, each polarization mode can be measured separately.

Fig. 5-18 : Transmission setup for Bragg wavelength measurement; TL : tunable laser, POLA : polarization controller, D : detector