Contents 1. INTRODUCTION
In recent years microstructured optical fiber (MOF) sensors have been largely investigated, due to their high versatility in developing new opto-fluidic sensing and actuating elements [1]. Combining photonic and microfluidic properties by infiltrating different matrices into the capillaries located along the cladding region of MOFs their guiding properties can be changed, allowing the development of smart optofluidic devices [2]. Recently, using such an approach, ferrofluids have been infiltrated in a grapefruit-type MOF where a Bragg grating was previously inscribed for developing magnetic fields optical sensors and actuator [3], [4]. A vectorial magnetometer utilizing a microstructured optical fiber Bragg grating has been implemented using this technology [5]. Under the application of magnetic field along the fiber axis, the magnetic liquid moves along the Bragg grating length, while inducing significant changes in the parasitic Fabry-Perot spectral notch observed in reflection.
