Bragg gratings inscribed in selectively inflated photonic crystal fibers

Abstract

We report a method for effective fabrication of Bragg gratings in all-silica photonic crystal fibers (PCF). The problem of cladding-hole scattering in PCF grating inscription is avoided by selectively inflating a section of PCF, resulting a locally suspended-core fiber (SCF) region with relatively simple cladding structure. Hence, the inscription laser can laterally access to the core region with little loss. In the SCF regions with core diameter ranging from 2 to 4.5 μm, first-order Bragg gratings are fabricated by use of a phase mask and a focused infrared femtosecond laser with pulse energy as low as ~200 μJ. For the same grating period, samples with different core sizes exhibit different resonant wavelengths and spectral properties, which would enable a range of applications in grating-integrated PCF sensors and devices.

Novel Fiber Grating for Sensing Applications

“…In order to efficiently inscribe an FBG by a femtosecond laser with low energy and short exposure time, Wang et al selectively inflate a section of the PCF and form a three‐hole suspended‐core fiber (SCF). Only one obvious dip was observed in the transmission spectrum of the optical implement with 4.5 µm core diameter in the SCF region, which was used to study the performances of strain, temperature, and RI.…”

Study of Temporal Thermal Response of Microfiber Bragg Grating

“…In the case of extreme environment such as corrosive, strong electromagnetic, flammable, and explosive, most of the traditional thermometers cannot meet the practical needs. Since silica fibers are good at high temperature stability, corrosion resistant, and anti-electromagnetic interference, silica-fiber based temperature sensors have attracted more and more attention recently [4][5][6][7][8]. Temporal thermal response of the sensing element is especially important for some rapidly changing and dynamic systems such as internal combustion engines.…”

Advances on Photonic Crystal Fiber Sensors and Applications

“…It is not exhaustive due to the very large literature production. The focus is on: (i) plasmonic [3,4,5,6,7,8,9,10,11,12,13,14], (ii) interferometric [15,16,17,18,19] and (iii) grating-based [20,21,22,23,24,25,26,27,28,29,30,31,32] PCF sensors, discussed in the following Section 2, Section 3 and Section 4, respectively. In other cases, innovative materials as graphene, polyvinyl alcohol, ferrofluid liquids, combined with the exploitation of conventional principles as the interferometry or the evanescent field interaction are simultaneously applied to obtain novel and promising devices.…”