- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
High Sensitivity Polarimetric Optical Fiber Pressure Sensor Based on Tapered Polarization-Maintaining and Fiber Bragg Grating
摘要： In this paper, we propose a high sensitivity polarimetric optical fiber pressure sensor (OFPS) using a polarization-diversity loop composed of a polarization beam splitter, polarization controllers, and a sensor head. The sensor head consists of 8-cm-long tapered panda-type polarization-maintaining fiber (PMF) and a fiber Bragg grating (FBG) directly spliced with PMF, and the sensor head is located inside a pressure chamber. A pressure-induced birefringence change due to the photoelastic effect can be greatly enhanced at the tapered section of PMF, thereby increasing the pressure sensitivity of the sensor head. The tapered PMF was fabricated using a fusion splicer, and the tapered length and center waist diameter of the tapered PMF segment were ～350 and ～56.82 μm, respectively. At the polarization-diversity loop, PMF is used as a birefringent element to create an interference spectrum due to polarization interference. A pressure-induced birefringence change of PMF results in a wavelength shift of the interference spectrum. Because the PMF birefringence also has a cross sensitivity to temperature, the FBG is utilized for the compensation of the temperature effect on it. The resonance wavelength of the FBG is sensitive to ambient temperature changes but insensitive to changes in pressure. This spectral response of the FBG can be used to compensate additional ambient temperature changes occurred at the sensor head. The pressure sensitivity of our sensor was measured as approximately ?27.70 nm/MPa, and an adjusted R2 value representing the sensor linearity was measured as ～0.9903 in a measurement range of 0–0.5 MPa. Our fabricated sensor exhibits the highest pressure sensitivity among previously reported polarimetric OFPS.
关键词： Polarization-Maintain Fiber,Optical Fiber Sensor,Sagnac Interferometer,Pressure
更新于2025-11-28 14:24:03
-
Polarization induced non-reciprocal phase controlled all-fiber loop mirror based inclinometer
摘要： An optical fiber inclinometer based on non-reciprocal phase change effect in a single-mode fiber loop mirror (FLM) is proposed. The phase of light waves in FLM is controlled by two-phase shifters (PSs). The relationship between the inclination angles and phase differences of the two-PSs, and transmitted light power was derived by Jones calculus. The signature of the birefringence obtained through simulation on the output light has been confirmed by experimentation. From the results, it was found that when the birefringence of the two-PSs are different, two measurement sensitivities (17.07 × 10?3 deg?1 and 21.37 × 10?3 deg?1) can be realized with one angle measurement system. We also report a method for changing measurable ranges, and measurement sensitivity. Since the angle can be directly measured from the transmitted light power, the results of this work contribute to the realization of simple and low-loss inclinometers using standard single-mode fiber.
关键词： Optical fiber inclinometer,Tilt measurement,Fiber optics,Sagnac interferometer,Fiber loop mirror
更新于2025-11-28 14:24:03
-
Temperature fiber sensor based on single longitudinal mode fiber laser in 2?μm band with Sagnac interferometer
摘要： A single longitudinal mode (SLM) ?ber laser with a ring cavity based on Sagnac interferometer (SI) for temperature sensing in the 2-μm band is proposed and demonstrated. The simulation and experimental results show that the transmission spectrum of the SI ?lter is sensitive to temperature change. Based on this distinguishing feature, the correlation between the laser wavelength drift and temperature variation can be established. Experimental results show that the proposed laser operates stably at the resonant wavelength of 1988.21 nm and the optical signal-to-noise ratio is approximately 55 dB at ambient temperature. Through continuous measurement for 100 min, the ?uctuation of the output laser power is lower than 0.74 dB, and the resonant wavelength shift is less than the minimum resolution of the spectrometer of 0.05 nm. This indicates that it has good stability for a certain period of time. At the same time, the laser operates stably in SLM state. A temperature sensitivity of 2.09 nm/°C is obtained in experiment. Notably, the proposed ?ber laser sensor possesses the merits including high sensitivity, low cost and simple structure, which are bene?cial to its practical application.
关键词： Fiber optics sensors,Temperature measurement,Sagnac interferometer,Fiber laser,2-μm band
更新于2025-11-28 14:23:57
-
Spatial-mode switchable, multi-wavelength all-fiber erbium-doped fiber (EDF) laser based on low modal crosstalk mode multiplexer/demultiplexer (MUX/DEMUX)
摘要： We experimentally demonstrate an all-fiber erbium-doped fiber ring laser based on a Sagnac interferometer with a low modal crosstalk mode multiplexer/demultiplexer (MUX/DEMUX). Three linearly polarized (LP) modes are generated by mode MUX/DEMUX, which consists of cascaded mode-selective couplers. The proposed fiber laser can simultaneously achieve spatial-mode switching and multi-wavelength tuning. In the experiment, single-, dual-, and triple-wavelength lasing outputs for LP01, LP11, LP21 and hybrid modes are obtained. The stabilities for LP01, LP11, LP21 and hybrid modes are investigated in more than 20 min, 16 min, 12 min and 16 min, respectively. Moreover, the mode intensity profiles, the OSNRs of the lasing output and the slope efficiencies are also measured.
关键词： multi-wavelength fiber laser,mode multiplexer/demultiplexer (MUX/DEMUX),spatial-mode switching,Sagnac interferometer
更新于2025-11-28 14:23:57
-
Modified Sagnac imaging spectropolarimeter for full linear Stokes parameters
摘要： A modified Sagnac imaging spectropolarimeter is conceptually described. It consists of a spectral-polarimetric modulator, a modified Sagnac interferometer with large optical path difference, and a CCD camera. This design modulates the Stokes components of the input light into different wave numbers and obtains the modulated interferogram in snapshot mode, and the spectra of the Stokes components can be separated and demodulated from the interferogram. The performance of the system is demonstrated through a numerical simulation, and a novel method is proposed to detect the polarization parameters including the degree of polarization and polarization direction for eliminating the aliasing effects between linear Stokes parameters. Compared with the existing imaging spectrometers, the modified Sagnac imaging spectropolarimeter can acquire one-dimensional spatial information and its full linear spectropolarimetric information in one exposure, and some other spatial information can be obtained by push-broom mode.
关键词： imaging spectropolarimeter,snapshot mode,Stokes parameters,polarization,Sagnac interferometer
更新于2025-09-23 15:23:52
-
Highly sensitive temperature sensor based on Sagnac interferometer with liquid crystal photonic crystal fibers
摘要： We propose and investigate a temperature sensor based on Sagnac interferometer with liquid crystal (LC) photonic crystal fiber (PCF) by finite element method (FEM). LC E7 which is anisotropic under electrical field is designed to be infiltrated into the cladding air holes of PCF. The birefringent PCF is then launched into a Sagnac interferometer. The interference spectrum of the Sagnac interferometer is influenced by the thermal effect of LC E7 and thus could be used to measure the temperature. The simulation results show that the temperature measuring sensitivity and resolution reach to 15 nm/K and 6.7E?4 K in the range of 290–320 K. The measuring range and sensitivity could be modified further by optimizing the PCF structure parameters.
关键词： Temperature sensor,Liquid crystal,Sagnac interferometer,Photonic crystal fiber
更新于2025-09-23 15:22:29
-
Demonstration of complementarity between path information and interference with thermal light
摘要： We report an experimental demonstration of complementarity between path information and interference in second-order correlation with thermal light. The key apparatus is a Sagnac interferometer in which an off-axis slit is inserted. Two orthogonal thermal light beams travel through the slit clockwise and anticlockwise in the interferometer. The second-order interference fringes vanish when the path information is acquired. The interference fringes are revived when the path information is effaced.
关键词： path information,second-order correlation,thermal light,Sagnac interferometer,complementarity,interference
更新于2025-09-23 15:22:29
-
Measuring weak magnetic field via dissipatively coupled opto-mechanical system
摘要： In this paper, we propose a scheme for the detection of weak magnetic field based on dissipatively coupled optomechanical system. The system considered here is composed of a perfect mirror and a compound mirror formed by a Michelson-Sagnac interferometer (MSI) with a movable membrane. When the transmissivity of MSI is close to zero, it sensitively depends upon the position of membrane. Under this condition, the two mirrors results in an effective Fabry-Perot interferometer (FPI) whose linewidth depends upon the position of the membrane. We show that by applying current to the membrane in the presence of magnetic field, the position of the membrane changes which in turn changes the linewidth of the effective FPI. This change can be observed in the spectrum of the output field and consequently enables us to measure weak magnetic field. Thus an optical detection technique is proposed for the detection of weak magnetic field.
关键词： Michelson-Sagnac interferometer,weak magnetic field,dissipatively coupled optomechanical system,optical detection technique,Fabry-Perot interferometer
更新于2025-09-12 10:27:22
-
Design of a remote and integrated Sagnac interferometer that can generate narrowband guided wave through the use of laser and effective optics to detect defects occurred in plates
摘要： To inspect the integrity of specimens that are moving or no space available to mount sensors on their surfaces, laser generated guided wave (GW) becomes the only feasible option. However, conventional GW generated by laser-based emission is in broadband frequency range. Hence, unwanted GW modes, along with the emitted desired GW mode, also get produced simultaneously to the inspected specimen. The results generated from reflected GW become chaotic, making the identification of GW signals truly reflected by defects very difficult. Hence, substantial research efforts have been spent on reducing unwanted GW modes by spatially modulating the laser pattern to emit narrowband GW. Previous methods to generate narrowband GW include the use of slit mask, diffractive grating, lenticular array, and interference of laser beam. Among these techniques, each has certain shortcomings. A recent research achievement is the design of the integrated optical Mach-Zehnder system (IOMZ) (J. Chen et al, Opt. Lett., 42, 4255, 2017). It can emit desired narrowband Lamb wave into the aluminum plate by using pulsed laser and the designed optical system. Although the results showed IOMZ’s ability in emitting narrowband GW mode, significant unwanted noise was also generated, making the signal-to-noise ratio (SNR) of the received GW signals rather low. In this study a new optical system to overcome the shortcoming of the above reported devices is proposed. It is called integrated Sagnac interferometer-based optical system (SIOS) which can minimize generation of unwanted noise and substantially improve the SNR of reflected GW signals. A comparison study is also presented to illustrate the effectiveness of SIOS is superior to that of the IOMZ. Experimental results reveal that the proposed SIOS is promising for remote nondestructive testing and evaluation.
关键词： Non-destructive testing,Laser,Optical systems,Narrowband laser generated ultrasound,Guided wave,Optical Sagnac interferometer
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - DeLLight: Deflection of Light by Light in Vacuum
摘要： Nonlinear electrodynamics in vacuum remains a relatively unexplored topic, as the intensities required to reach the nonlinear regime make it dif?cult to test in the laboratory. There are thus several competing theories of nonlinear electrodynamics, distinct from each other in theory but not yet having been ruled out by experiment [1,2]. The standard theory (derived from QED) is the Heisenberg-Euler model, which treats vacuum as a polarizable medium through the production of virtual electron-positron pairs. This model has had success in explaining (for example) the Lamb shift in hydrogen, but in recent years signi?cant discrepancies (of ～ 7 σ ) have appeared when applied to muonic hydrogen and muonic deuterium, where the heavier muon is 200 times closer to the nucleus and thus experiences a much stronger electric ?eld [3,4]. To date, the most sensitive tests of nonlinear electrodynamics, performed by the collaborations PVLAS in Italy [5] and BMV in Toulouse [6], have aimed at detecting the birefringence of vacuum induced by a strong external magnetic ?eld. However, the regime in which these tests are conducted currently lies one to two orders of magnitude above the Heisenberg-Euler regime, and the results are compatible with there being no birefringence at all, as predicted by, e.g., the Born-Infeld model. The goal of the DeLLight project [7] is to provide an experimental test of nonlinear QED through changes in the effective refractive index of vacuum, independently of any birefringence effects. A short, intense laser pulse polarizes the vacuum, and the effective index variation thus induced is probed using a second laser pulse of much lower intensity. The relative displacement of the pulses is such that the probe straddles the edge of the pump and experiences a refractive index gradient, thereby de?ecting its trajectory by a small angle. This de?ection can be brought into a detectable range by having the probe form one beam of a Sagnac interferometer, the other beam being a control pulse which does not interact with the pump. The interference between the two ampli?es the transverse barycentre shift in the intensity of the output signal, by a factor which depends on the extinction factor of the Sagnac interferometer. The resultant shift is statistically measurable through the collection of a large number of experimental results. We have tested this experimental technique on measurements of a very similar pump/probe interaction which is due to the Kerr nonlinearity in silica. The theoretical description of the vacuum nonlinearity proceeds as follows. Starting from a general Lagrangian that respects Lorentz and parity invariance, and restricting nonlinear terms to their lowest nontrivial order, the nonlinearities of the electromagnetic ?eld equations depend on two parameters [1]. These are model-dependent; in particular, they are completely ?xed by the Heisenberg-Euler theory, and we use its values when making physical predictions. The nonlinear equations are linearized around a strong background ?eld con?guration, providing approximate ?eld equations for a probe ?eld which is signi?cantly weaker in intensity than the background. This treatment yields a description of the background as an effective medium, which is generally bi-anisotropic in nature. However, for the simple case of two counter-propagating pulses, it provides simple expressions for the nonlinear index of the pump, which depends on the relative polarization between pump and probe. The DeLLight measurement is thus sensitive to, but not dependent on, birefringence effects in nonlinear electromagnetism. Numerical simulations show that the de?ection of the probe is well described by the linear medium formalism, and allow us to investigate the dependence of the de?ection on various experimental parameters. For typical pump pulses provided by the LASERIX facility [8] (energy ～ 2 J, wavelength ～ 800 nm, duration ～ 30 fs), and assuming minimum waists of both pulse and probe ～ 5 μm, we ?nd an average de?ection of the order of 0.02 picoradian. This can be ampli?ed by a factor of ～ 250 using the Sagnac interferometer with the achieved extinction factor, which over a distance of 0.5 m corresponds to a transverse barycentre shift of ～ 0.01 nm. For a pulse repetition rate of ～ 10 Hz and the present high well-depth CCD cameras, the expected signal could be measured with a con?dence level of ～ 3 σ in about 20 days.
关键词： Nonlinear electrodynamics,Sagnac interferometer,vacuum,Heisenberg-Euler model,birefringence
更新于2025-09-12 10:27:22