Direct core structuring of microstructured optical fibers using focused ion beam milling

Abstract

We demonstrate the use of focused ion beam milling to machine optical structures directly into the core of microstructured optical fibers. The particular fiber used was exposed-core microstructured optical fiber, which allowed direct access to the optically guiding core. Two different designs of Fabry-Perot cavity were fabricated and optically characterized. The first cavity was formed by completely removing a section of the fiber core, while the second cavity consisted of a shallow slot milled into the core, leaving the majority of the core intact. This work highlights the possibility of machining complex optical devices directly onto the core of microstructured optical fibers using focused ion beam milling for applications including environmental, chemical, and biological sensing.

Tuning of Fiber Optic Surface Reflectivity through Graphene Oxide-Based Layer-by-Layer Film Coatings

“…The obtained values reveal that adsorption of the first GO layer is much slower than for the tenth GO layer, which is in accordance with the literature, specifically for the case of kinetic curves of polyaniline, a conducting polyelectrolyte whose All the fitting parameters are included in Table 1. The obtained values reveal that adsorption of the first GO layer is much slower than for the tenth GO layer, which is in accordance with the literature, specifically for the case of kinetic curves of polyaniline, a conducting polyelectrolyte whose adsorption characteristic time decreases strongly as the number of bilayers already adsorbed increases [33]. The adsorbed amount is seen to increase with the number of adsorbed bilayers already adsorbed due to an increase in surface roughness of the LbL film, as demonstrated by Ferreira et al [36] and, therefore, also demonstrating that one cannot expect these GO films to be uniform.…”

“…By performing a fast Fourier transform (FFT), it is possible to calculate the air cavity length as well as silica wall thickness. Prior to applying the FFT, the spectrum wavelength data was converted to optical frequency since the free spectral range was uniform in optical frequency but not in wavelength [33]. Seen in the FFT, in Figure 3b, two main peaks are visible.…”

Simultaneous measurement of temperature and refractive index using focused ion beam milled Fabry-Perot cavities in optical fiber micro-tips

“…The spectra before Before performing the FFTs, the wavelength data was converted to optical frequency because the free spectral range is uniform in optical frequency but not in wavelength, where it depends on the square of the wavelength [24].…”

“…Cavities in microwires for temperature and vibration sensing have been shown [20] as well as focused ion beam milled cavities in polished optical fibers [21]. FIB milling has even been demonstrated in exposed-core suspended core fibers [24].…”

Fiber Microstructure Sensors Based on Focused Ion Beam Technology

“…Fabry-Perot cavities have also been milled in exposed core microstructured optical fibers (ECF). The Fabry-Perot cavities were milled directly into the core of ECF [34]. Due to the easy access to the core, it was possible to directly create the cavity on the fiber core without making previous use of any low resolution technique.…”