A fiber-optic Fabry-Pérot acoustic sensor with a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${\sim}{100}\hbox{-}{\rm nm}$</tex></formula> -thick multilayer graphene diaphragm is reported. Acoustic testing demonstrates pressure-induced deflection of 1100 nm/kPa and noise equivalent signal level xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\sim}{\rm 60}~\mu{\rm Pa}/{\rm...

Long period gratings (LPGs) are fabricated by use of focused high frequency CO 2 laser pulses to periodically modify the transverse dimension silica microfibers.A 20-period LPG with a 27dB attenuation dip is realized in microfiber diameter ~6.3µm.The resonant wavelength has negative temperature coefficient and sensitivity external refractive index.The LPGs may be useful micron scale in-fiber devices sensors.

Long period fiber gratings in hollow-core air-silica photonic bandgap fibers were produced by use of high frequency, short duration, CO 2 laser pulses to periodically modify the size, shape and distribution air holes microstructured cladding.The resonant wavelength these is highly sensitivity strain but insensitive temperature, bend external refractive index.These can be used as stable spectral filters novel sensors.

Abstract With the recent development of wearable electronics and smart textiles, flexible sensor technology is gaining increasing attention. Compared to film‐based sensors, multimaterial fiber‐based offers unique advantages due breathability, durability, wear resistance, stretchability in fabric structures. Despite significant progress made fabrication application none existing fiber technologies allow for fully distributed pressure or temperature sensing. Herein, design thermally drawn...

Highly birefringent (Hi-Bi) air-clad silica microfibers (MFs) with wavelength and sub-wavelength scale transverse dimensions are studied theoretically experimentally.Hi-Bi MFs taper-drawn from the standard SMF-28 single mode fibers that "pre-processed" by "cutting away" parts of cladding on opposite sides fiber a femtosecond infrared laser.Such Hi-Bi have approximately elliptical cross-sections approximated three-layer model comprising small central Ge-doped region surrounded an...

We report the fabrication of long-period gratings (LPGs) in wavelength-scale microfibers with diameters from 1.5to3 μm. The LPGs were fabricated by use a femtosecond IR laser to periodically modify surface fibers. These have grating periods few tens micrometers, much smaller than those conventional optical A compact 10-period LPG device length only ~150 μm demonstrated strong resonant dip >20 dB around 1330 nm. microfiber would be useful in-fiber components for microfiber-based devices,...

Compact ferrule-top nanomechanical resonators with multilayer graphene (MLG) diaphragms as vibrating elements are demonstrated. The comprise a suspended MLG film supported by ceramic ferrule bore diameter of ∼125 μm. mechanical resonance the is excited and detected an all-fiber optical interrogation system. Based on beam-shape resonator, force sensitivity ∼3.8 fN/Hz1/2 was theoretically predicted. integration fiber simplifies excitation resonator would allow development practical fiber-optic...

This paper examines the unique properties of hollow-core photonic bandgap fibers and discusses potential sensing applications such fibers. Guidance light in air instead silica reduces effect material on propagation is advantageous to as fiber gyroscopes. An air–silica microstructure has novel mechanical thermal can be beneficial acoustic pressure sensors. Holey cladding provides extra flexibility for geometry modification through post treatment or selective filling holes exploited developing...

Highly birefringent (Hi-Bi) microfiber-based fiber loop mirrors (FLMs) were studied for tunable comb filters and refractive index (RI) sensors. The use of two cascaded Hi-Bi microfibers instead a single microfiber allows more flexibility in controlling the transmission/reflection characteristics FLM. length is order centimeters, one or even than orders magnitude shorter conventional fiber-based FLM devices. spectra are sensitive to RI surrounding microfibers, sensitivity 20,745 nm/RIU was...

We report the fabrication of in-line photonic microcells (PMCs) by encapsulating tapered microfibers (MFs) inside glass tubes. The encapsulation isolates MFs from external environment and makes them more suitable for real-world applications. Based on PMCs with encapsulated highly birefringent (Hi-Bi) MFs, we demonstrated pressure, temperature refractive index (RI) sensors as well long period grating devices. A fiber Sagnac loop interferometer incorporating a Hi-Bi microfiber PMC RI...

We report a different mechanism for rotation sensing by analyzing the polarization of light exiting from Sagnac loop. Unlike in an interferometric fiber optic gyroscope (I-FOG), here counter-propagating waves loop are orthogonally polarized at exit and, consequently, cannot directly interfere with each other when recombined exit. show that Stokes parameters s2 and s3 combined simply cosine sine functions phase difference between counter propagation waves, which is linearly proportional to...

Broadband, compact in-fiber polarizers were fabricated using a pulsed CO(2) laser to modify the air holes along one side of hollow-core photonic bandgap fibers. The have lengths from 3 6 mm and exhibit polarization extinction ratio better than 20 dB over wavelength range larger 100 nm at approximately 1,550 nm.

We investigate the phase sensitivity of fundamental mode hollow-core photonic bandgap fibers to strain and acoustic pressure.A theoretical model is constructed analyze effect axial pressure on effective refractive index mode.Simulation shows that, for commercial HC-1550-02 fiber, contribution mode-index variation overall sensitivities are respectively ~-2% ~-17%.The calculated normalized phase-sensitivities fiber 1 ε -1 -331.6 dB re µPa without considering variation, 0.9797 -333.1 when...

In-fiber polarimeters or polarization mode interferometers (PMIs) are fabricated by cascading two CO2-laser-induced in-fiber polarizers along a piece of hollow-core photonic bandgap fiber.Since the interfering beams orthogonal polarizations fundamental mode, which tightly confined to core and have much lower loss than higher order modes, PMIs can either short (e.g., few millimeters) long (tens meters longer) device length without significantly changing fringe contrast hence provide design...

A novel type of polarization converters (PCs) based on highly birefringent (Hi-Bi) microfibers is presented.Analytical formulation the Jones Matrix method and a numerical code Full Vectorial Finite Difference Beam Propagation Method are developed to analyze evolutions in such PCs.Two different design configurations, namely "one-side" "two-side" perturbation studied by use two methods, results obtained agree well with each others.The PCs can be flexibly designed have operating wavelengths,...

A type of single crystal sapphire optical fiber (SCSF) design is proposed to reduce the number guided modes via a highly dispersive cladding with periodic array high- and low-index regions in azimuthal direction. The structure retains "core" region pure (SC) center "cladding" alternating layers air SC direction that uniform radial modal characteristics confinement losses fundamental mode were analyzed finite element method by varying effective core diameter dimensions "windmill"-shaped...

We present a large-core single-mode "windmill" single crystal sapphire optical fiber (SCSF) design, which exhibits operation by stripping off the higher-order modes (HOMs) while maintaining fundamental mode. The SCSF design was analyzed using finite element analysis method, in all HOMs are leaky. numerical simulation results show spectral range from 0.4 to 2 μm windmill SCSF, with an effective core diameter as large 14 μm. Such is expected improve performance of many current optic sensor structures.

In this paper we propose a new and cost-effective fabrication scheme for porous polymer optical fibers. Different fibers made from polycarbonate (PC) poly(methyl methacrylate) (PMMA) using method have been thermally drawn characterized. Porosity in the fiber cladding is introduced by absorbed water one layer of preforms under heat treatment and/or thermal drawing, can be controlled adjusting concentration. addition, shown that fabricated potential application localized drug delivery cancer treatment.

A novel concept of acoustic fiber Bragg grating (AFBG) was conceived and experimentally validated as an effective technique for high-temperature sensing. Similar to the well-known optical grating, AFBG employs interactions between waves periodic structures on elongated waveguide. Acoustic reflected from interfere with each other result in emergence resonance frequency when wavelength matches pitch length structures. When single-mode operation condition is satisfied, location can be...

A series of low-contract photonic band-gap (PBG) fibers were fabricated by filling the holes a commercial air-silica hollow-core PBG fiber with different refractive index liquids. The PBGs and transmission characteristics these investigated theoretically experimentally. An increase in liquid causes blue-shift narrow down width, which may be exploited for sensitive measurement.

We report novel rocking long period gratings (R-LPGs) made by introducing permanent periodic twist along a standard single mode fiber. Very high coupling efficiency of 32.5 dB was achieved with 23 periods and 2° angle. The responses R-LPGs to temperature, strain, torsion were tested. Compared normal LPG written under the same conditions, found have similar sensitivity five times smaller insensitive twist.

We report the first fabrication, to our knowledge, of polarization-rocking filters in highly birefringent elliptical microfibers. A rocking filter was made by periodically heating/twisting a microfiber with an ellipticity ∼0.7 and diameter ∼2.8 μm along its major axis. Strong input polarization suppression ∼20 dB achieved at resonant wavelength ∼1556.4 nm device length ∼3 mm.

Highly birefringent (Hi-Bi) microfiber-based fiber loop mirrors (FLMs) are studied for gas pressure measurement. A elliptical microfiber is made by tapering a femtosecond laser-processed single mode and demonstrated very high birefringence of up to 10^-2 . The housed within tube with which measurement carried out. robust sensor demonstrates sensitivity 6 pm/kPa temperature cross-sensitivity less than 0.01 nm/K.

We report the fabrication of long-period gratings (LPGs) in highly birefringent (Hi-Bi) microfibers. The LPGs were fabricated by using a femtosecond infrared laser to modify surface or CO2 induce micro-tapers periodically along Hi-Bi These have pitches from tens hundreds micrometers and very strong polarization dependent resonances. A LPG on microfiber with major-diameter ~2.8 μm an ellipticity ~0.7 demonstrated refractive index sensitivity ~4623 nm/RIU water.

Fiber Bragg gratings (FBGs) in the center of multimode microfibers (MM-MF) with 10μm diameter were successfully inscribed point-by-point method and their reflection spectra show peaks over 10dB signal-to-noise ratio (SNR) less than 0.5nm bandwidth. FBGs on regular size fiber (~60μm core size) shows nearly continuous spectrum. However, when is reduced to ~10μm, its modal volume significantly decreases so that remaining optical modes are separated by larger propagation constant difference,...