A compact and simple fiber in-line modal interferometer with an embedded Bragg grating (FBG) is proposed experimentally demonstrated for simultaneous measurement of refractive index temperature. The in-fiber formed by cascading two offset-splicing joints in a section inscribed FBG. interference pattern the shifts ambient temperature variation, while wavelength FBG only sensitive to temperature, so device can solve cross-sensitivity measure dual parameters simultaneously. sensitivities -26.22...

A novel label-free optical fiber biosensor, based on a microcavity Mach–Zehnder interferometer, was developed and practically demonstrated for DNA detection. The biosensor fabricated using offset splicing standard communication single-mode fibers (SMFs). light path of the sensor influenced by liquid sample in open cavity. In experiment, high sensitivity −17,905 nm/RIU achieved refractive index (RI) measurement. On this basis, probe (pDNA) immobilized onto sensor’s surface APTES, enabling...

A sensing system for simultaneously measuring strain and temperature is proposed by employing a polarimetric multilongitudinal mode fiber laser sensor beat frequency demodulation device. The built with two Bragg gratings piece of Erbium-doped-fiber, which act as cavity reflector gain medium, respectively. Owing to the intrinsic birefringence fiber, orthogonal polarization modes experience slight splitting, thus many longitudinal signals are generated in cavity. Strain can be measured...

A Mach-Zehnder interferometer based on cascaded long-period gratings with a hydrogel thin-film coating is developed for monitoring the relative humidity (RH). The visibility of fringes and phase shift are measured using Fourier analysis. sensors show good linearity from 60%RH to 100%RH ability measure below 60% at reduced accuracy shift. An RH 0.4% achieved.

A novel lateral stress sensor based on a compact in-fiber Mach-Zehnder interferometer (MZI) and Fourier analysis is proposed demonstrated. The MZI formed by cascading two offset splicing joints. interference occurs between the copropagating fundamental core cladding modes. influence of value performance modal interferometer, including extinction ratio insertion loss, has been experimentally investigated. spatial spectra interferometers with different lengths are analyzed transform. An an...

A large-scale multilongitudinal mode fiber laser sensor array is proposed and demonstrated experimentally based on wavelength/frequency division multiplexing beat frequency demodulation technique. In the hybrid sensing system, realized by designing n lasers with different cavity lengths, while wavelength achieved incorporating a 1 × m coupler an m-channel demultiplexer. By making operating of frequency-multiplexed equal to central each channel in demultiplexer, light coupled independently...

A five-channel frequency-division multiplexing (FDM) fiber laser sensor array based on multilongitudinal mode lasers (MLMFLs) and beat frequency demodulation was proposed. Detailed theoretical analysis of the FDM principle also described. The potential application MLMFL-based for strain measurement further experimentally studied. sensitivity -0.92 kHz/με at 1183.52 MHz is consistent with calculation. proposed sensing system only needs one detector general analyzer monitoring all sensors....

A novel and low-cost fiber birefringence measurement scheme is proposed studied by a polarimetric ring laser interrogated the beat frequency technique. For laser, modes splitting occur between two orthogonal polarization because of intrinsic birefringence. As result, types signals (i.e., longitudinal mode signals) are generated simultaneously. The principle has been analyzed theoretically in detail. Two alternative expressions for change obtained, which very convenient users to choose...

A low-cost and real-time frequency division multiplexing system is proposed based on multi-longitudinal mode fiber laser sensor array beat signal demodulation technology. The lasers have staggered cavity lengths with corresponding spacing. Beat signals of the longitudinal modes each in are detected by a common detector. relationship worked out between maximum number sensors detectable frequency. four investigated experimentally its potential application for strain measurement also...

In order to improve the efficiency and accuracy of multitarget detection soldering defects on surface-mounted components in Printed Circuit Board (PCB) fabrication, we propose a sample generation method using Stable Diffusion Model ControlNet, as well defect based Swin Transformer. The consists two stages: First, high-definition original images collected industrial production corresponding prompts are input ControlNet for automatic nonindependent samples. Subsequently, integrate Transformer...

Abstract We systematically analyze the mode‐coupling effects of stress‐induced long‐period gratings (LPGs) using photonic crystal fiber (PCF). Two Mach–Zehnder interferometers based on this grating are demonstrated. These devices offer unique advantages being tunable and reconfigurable. Their good interfering efficiency makes them promising for wavelength‐selective filters in WDM communication systems. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1379–1383, 2006; Published...

A novel method for characterizing the tensile properties of AISI 1045 steel is proposed by combining in situ nanoindentation test and theory mesomechanical analysis. First, load–depth curves exact location ferrite, pearlite grain boundary on surface are obtained 30 groups tests. The constitutive equation (stress–strain function) real-time metallographic structure analysis above curves. Then, based principle analysis, computational representative volume element models reconstructed according...

We present an in-fiber Mach-Zehnder type interferometer (MZI) in single mode fiber based on lateral offset splicing technique. The MZI relies the interference between fundamental core and a co-propagating cladding mode. To build MZI, we need one element or device which excites two modes another to recombine them. In our case, excitation recombination of is realized by cascaded joints. effects amount, cavity length, fusion parameters property performance were investigated experimentally. By...

A real-time interrogation technology for a large-scale fiber laser sensor array is proposed and experimentally investigated by employing hybrid topological structure based on the wavelength- frequency-division multiplexing techniques. In this system, 2-D n × m established using 1 coupler couplers. All sensors are divided into units coupler. each unit, there fiber-ring with approximately same wavelength different beat frequencies due to cavity lengths. Meanwhile, characteristic of operating...

In the present study, two kinds of TiO2/EG composite nanocatalysts were fabricated through different procedures. Subsequently, resulting samples characterized scanning electron microscope (SEM), X-ray diffraction (XRD), UV-visible light diffuse reflection spectrum (UV-vis DRS) and exfoliated volume (EV) measurements. Results showed that both displayed an obviously enhanced visible absorbance. Besides, S-TiO2/EG nanocatalyst exhibited higher adsorptive photocatalytic (PC) performance than...

A method for testing the physical and optical properties of hydrogel thin films is reported based on using long-period fiber gratings. For humidity levels from 50% to 70% RH, a wavelength decrease 11.0 nm observed, with sensitivity 0.6 nm/%RH. 98% increase 6.3 seen, 0.2 greater than 60% transmission loss at resonance increases rapidly, showing high degree 0.5 dB/% RH. The blueshift was seen be due thickening overlay, while redshift contribution drop in refractive index overlay. results match...

The Letter describes a hybrid multiplexing scheme for multi-longitudinal-mode fiber laser sensor array by combining wavelength-division and frequency-division techniques. proposed system consists of many subgroups, each which has sensors with approximately equal laser-operating wavelengths but different cavity lengths. Each in one subgroup can be interrogated using technology because beat frequencies. For they are characteristic wavelengths. divided into the designed channel dense...

We report a compact in-fiber Mach-Zehnder interferometer (MZI) made along hollow-core photonic bandgap fiber (HC-PBF). The MZI uses long period grating (LPG) and an offset-splice joint (OSJ) which act as beam splitter combiner respectively. LPG was produced by use of high frequency pulsed CO2 laser, the OSJ in serial with using commercial fusion splicer. interference is between fundamental core mode (FCM) high-order (HOCM). proposed experimentally tested for temperature strain measurements,...

With the deepening of population aging in China, there is an urgent need for excellent geriatric nursing professionals. However, are still problems current professional education, such as disconnect between theory and practice, leading to uneven quality talent t