We report the first experimental demonstration of a humidity insensitive polymer optical fiber Bragg grating (FBG), as well FBG recorded in TOPAS important low loss 850 nm spectral region. For we have fabricated FBGs with resonance wavelength around and 1550 single-mode microstructured fibers made conventional poly (methyl methacrylate) (PMMA). Characterization shows that is more than 50 times less sensitive to PMMA both regimes. This makes very appealing for sensing applications it appears...

Photosensitivity in optical fibres properties of Fibre Bragg gratings inscribing grating theory applications communications sensors impact gratings.

We report observations and measurements of the inscription fiber Bragg gratings (FBGs) in two different types microstructured polymer optical fiber: few-mode an endlessly single mode. Contrary to FBG silica fiber, where high-energy laser pulses are a prerequisite, we have successfully used low-power cw source operating at 325 nm produce 1 cm long with reflection peak 1570 nm. Peak reflectivities more than 10% been observed.

We report on the first inscription of fiber Bragg gratings (FBGs) in cyclic transparent optical polymer (CYTOP)-perfluorinated fibers (POFs). have used a direct write method with femtosecond laser operating visible. The FBGs typical reflectivity 70%, bandwidth 0.25 nm, 3-mm length, and an index change ~10-4. operate C-band, where CYTOP offers key advantages over polymethyl methacrylate fibers, displaying significantly lower loss important near-infrared (NIR) communications window. In...

We report on an optical bend sensor based a Bragg grating inscribed in eccentric core polymer fiber. The device exhibits the strong fiber orientation dependence, wide curvature range of ±22.7 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and high sensitivity 63 pm/m .

We report on the development and characterization of single peak fiber Bragg gratings (FBGs) in polymer optical (POF). use a multimode gradient index cyclic transparent (CYTOP) fiber, where FBGs are inscribed with femtosecond laser. adapt direct-write, plane-by-plane inscription method, beam is scanned transversely across core, to create refractive changes. In order reduce number modes coupling grating, we limit FBG's spatial extent central part region profile peaks. this way, able excite...

This paper presents the development of a three-dimensional (3-D) displacement sensor based on one fiber Bragg grating (FBG). In order to obtain higher sensitivity and dynamic range, FBG is inscribed in low-loss, multimode, cyclic transparent amorphous fluoropolymers using direct-write, plane-by-plane femtosecond laser inscription method. The proposed influence each condition, namely, axial strain, torsion, bending reflection spectrum. Such analyzed with respect wavelength shift,...

This paper demonstrates the use of polymer optical fiber Bragg gratings (POFBGs) for angle measurements over a range different oscillatory frequencies. The POFBGs are inscribed in low-loss, cyclic transparent amorphous fluoropolymers (CYTOP) and imprinted using direct-write, plane-by-plane femtosecond laser inscription method. As has viscoelastic response given that Young's modulus depends on frequency, compensation technique sensor frequency cross-sensitivity hysteresis is proposed...

We report the application of fiber Bragg grating (FBG) arrays in polymer optical fibers for quasi-distributed displacement and torque sensing a series elastic actuator's spring. The were inscribed cyclic transparent through direct-write, plane-by-plane inscription method using femtosecond laser. Two with four FBGs each positioned on rotary spring, numerical analysis finite-element was performed to evaluate sensors' behavior under different loading conditions. Experimental tests results show...

We report on the thermal characteristics of Bragg gratings fabricated in polymer optical fibers. have observed a permanent shift grating wavelength at room temperature which occurs when has been heated above threshold temperature. This is dependent history grating, and we attribute effect to shrinking fiber. can be avoided by annealing fiber before inscription, resulting linear response with an increased operating range grating.

A report is presented on the inscription of a fibre Bragg grating into microstructured polymer optical fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed basis for gratings: much lower water affinity and useful properties biosensing. The had wavelength 1569 nm temperature sensitivity −36.5±0.3 pm/°C.

We report on the development of a multiplexed sensor array fiber Bragg gratings (FBGs), inscribed using femtosecond laser, and its demonstration as quasi-distributed to capture mode shapes, through surface displacement sampling, free-free vibrating beam. Our method is based plane-by-plane inscription approach, whereby 2-D index change written across core, controlling width depth modified region. This allows for fast multiple wavelength FBGs in coated optical fibers, with advantage less...

In this Letter, we report a flexible, plane-by-plane direct write inscription method for the development of tailored, tilted fiber Bragg gratings using femtosecond laser. Compared to ultraviolet or laser based on phase mask, interferometric, point-by-point methods, presented approach is far more flexible and offers several advantages. Laser made through coating, while grating planes are controlled minimize birefringence, with precise control over wavelength location strength cladding modes....

We propose a novel polymer optical fiber (POF) sensing system based on Bragg gratings (FBGs) to measure foot plantar pressure. The pressure signals are detected by five FBGs, in the same piece of cyclic transparent (CYTOP) fiber, which embedded cork insole for dynamic monitoring gait. calibration and measurements performed with suggested presented, results obtained demonstrate accuracy reliability platform monitor distribution during gait motion application This architecture does not...

In this paper, we investigate the influence of temperature on transverse force response polymer optical fiber Bragg gratings (POFBGs) inscribed in cyclic transparent fluoropolymers (CYTOPs). The are imprinted using direct-write, plane-by-plane femtosecond laser inscription method. increase leads to a decrease Young's modulus, which causes sensitivity variation POFBG sensor for applications. proposed technique is based characterization both sensor's offset and material's modulus due increase....

We investigate the modification of optical properties carbon nanotubes (CNTs) resulting from a chemical reaction triggered by presence specific compound (gaseous dioxide (CO2)) and show this mechanism has important consequences for sensing. CNTs have attracted significant research interest because they can be functionalized particular chemical, yielding physical response which suggests many potential applications in fields nanotechnology So far, however, utilizing their purpose proven to...

We developed a flexible support with embedded polymer optical fiber (POF) sensors for the assessment of human–robot interaction forces. The supports were fabricated three-dimensional (3D) printer, where an acrylonitrile butadiene styrene (ABS) rigid structure was used in region which exoskeleton attached, whereas thermoplastic polyurethane (TPU) printed users placed their legs. In addition, Bragg gratings (FBGs), inscribed low-loss, cyclic, transparent, (CYTOP) using direct-write,...

We present results for the mechanical characterization of a bisphenol-A acrylate-based polymer optical fiber (POF) manufactured using novel light polymerization spinning (LPS) process. The particular manufacturing process allows development POFs having unique characteristics, which result from an exceptionally low Young's modulus. lower modulus enables sensors measuring stress or pressure with improved sensitivity and potentially higher tunable range than conventional POFs. Moreover,...

We investigate the hydrostatic pressure dependence of Bragg wavelength a fiber grating (FBG) inscribed in perfluorinated graded-index (PFGI-) polymer optical (POF) at 1550 nm. At 0.5 MPa, increased with time and became almost constant ~150 min later. Such long probably originates from unique structure PFGI-POF, which has thick overcladding around its core cladding. The pressure-dependence coefficient without considering was estimated to be 1.3 nm/MPa; this is over five times values other...

A long period grating has been fabricated in endlessly singlemode photonic crystal fibre using a spatially-periodic electric arc discharge. The sensing characteristics of the have studied and it was found to possess an insensitivity temperature, bend sensitivity 3.7 nm · m strain −2.0 pm/µɛ