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Double Imaging Mach–Zehnder Spatial Carrier Digital Shearography
摘要： This paper presents a Double Imaging Mach–Zehnder Spatial Carrier Digital Shearography (DIM-SCDS) system. Compared to traditional Spatial Carrier Mach–Zehnder shearography, DIM-SCDS has two advantages: one is that it can adjust shearing amount and spatial carrier frequency independently; the other one is that it can measure a larger area with a shorter working distance. Two pairs of imaging lenses and apertures are placed in the two arms of Mach–Zehnder interferometry, respectively. Shearing amount is adjusted by the mirrors in the two arms, and spatial carrier frequency is determined by the angle between the two apertures when they are mapped to the same optical axis. Shearograms of the object under test are recorded using a CCD. Shearogram phases are calculated as the measurement results. Finally, the performance of DIM-SCDS is proved by experiments.
关键词： Mach–Zehnder interferometer,spatial carrier,dynamic measurement,Digital shearography
更新于2025-09-09 09:28:46
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Hybrid structure Mach–Zehnder interferometer based on silica and fluorinated polyimide microfibers for temperature or salinity sensing in seawater
摘要： An all-fiber hybrid structure Mach-Zehnder interferometer (MZI) based on silica fiber and fluorinated polyimide microfiber (FPMF) for temperature or salinity sensing in seawater is proposed. Theoretically, transmission characteristic and sensing sensitivity of the MZI are derived for this kind of hybrid structure, and typical interference spectrum is observed around optical communication band. Experimentally, by tracking the shift of interference peaks, temperature and salinity sensing are demonstrated with sensitivities of about 140pm/°C and 64pm/‰, respectively, which are much higher than those of existing fiber Bragg gratings and microfiber knot resonators. In addition, dependences of sensitivity on sensor parameters, such as fiber diameter and fiber lengths, are also investigated. Unlike the other microfiber based sensors that higher sensitivity usually comes from the thinner fiber, sensors demonstrated here show that sensitivities can be tuned by changing the path-length difference of the two arms, which greatly decreases the difficulty in component fabrications. Temperature or salinity sensor demonstrated here show advantages of simple fabrication, low cost, tunable sensitivity and dynamic range, relatively high sensitivity and compatible with standard fiber optics system, which may have potential applications in developing low cost and compact size optical sensors in ocean or other liquid surroundings.
关键词： salinity,temperature,hybrid structure,microfiber,Optical fiber sensor,Mach-Zehnder interferometer
更新于2025-09-09 09:28:46
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Studies on Temperature and Strain Sensitivities of a Few-mode Critical Wavelength Fiber Optic Sensor
摘要： This paper studied the relationship between the temperature/strain wavelength sensitivity of a fiber optic in-line Mach-Zehnder Interferometer (MZI) sensor and the wavelength separation of the measured wavelength to the critical wavelength (CWL) in a CWL-existed interference spectrum formed by interference between LP01 and LP02 modes. The in-line MZI fiber optic sensor has been constructed by splicing a section of specially designed few-mode fiber (FMF), which support LP01 and LP02 modes propagating in the fiber, between two pieces of single mode fiber. The propagation constant difference, Δβ, between the LP01 and LP02 modes, changes non-monotonously with wavelength and reaches a maximum at the CWL. As a result, in sensor operation, peaks on the different sides of the CWL then shift in opposite directions, and the associated temperature/strain sensitivities increase significantly when the measured wavelength points become close to the CWL, from both sides of the CWL. A theoretical analysis carried out has predicted that with this temperature/strain sensor approach, the temperature/strain wavelength sensitivities are governed by the wavelength difference between the measured wavelength and the CWL. This conclusion was seen to agree well with the experimental results obtained. Combining the wavelength shifts of the peaks and the CWL in the transmission spectrum of the SFS structure, this study has shown that this approach forms the basis of effective designs of high sensitivity sensors for multi-parameter detection and offering a large measurement range to satisfy the requirements needed for better industrial measurements.
关键词： few mode fiber,temperature sensitivity,In-line Mach-Zehnder interferometer,strain sensitivity,critical wavelength
更新于2025-09-09 09:28:46
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Performance comparison of Fabry-Perot and Mach-Zehnder interferometers for Doppler lidar based on double-edge technique
摘要： Compared with dual-channel Fabry-Perot interferometer (DFPI), dual-channel Mach-Zehnder interferometer (DMZI) is a new frequency discriminator for Doppler wind lidar based on double-edge detection. The double-edge frequency discrimination systems based on DFPI and DMZI in the wind lidar system are designed, respectively, and the detection principle is analyzed theoretically. Under certain simulation conditions, performances such as line-of-sight (LOS) wind velocity measurement sensitivities, signal-to-noise ratios (SNR) and LOS wind velocity measurement errors of both DFPI and DMZI systems are simulated and compared based on the U.S. standard atmospheric model. The simulation results show that for 1064nm aerosol system, the LOS wind velocity measurement sensitivity of the DMZI system is lower than that of DFPI system and the error is higher than that of DFPI system with the same dynamic wind velocity measurement range. Nevertheless, for 355nm atmospheric molecular system, DMZI system provides a factor of 1.33 times lower error in the LOS wind velocity than that of DFPI with an altitude of 30 km and the LOS wind velocity of 200m/s. Furthermore, in the LOS wind velocity range of -200m/s~+200m/s, the measurement error of DMZI system hardly increases with the increasing of wind speed. Therefore, the results of this study not only provide guidance for the selection of discriminators, but also provide theoretical support for the application of DMZI in the double-edge detection of atmospheric molecular lidar.
关键词： dual-channel Fabry-Perot interferometer,Doppler lidar,wind velocity measurement,dual-channel Mach-Zehnder interferometer,double-edge detection
更新于2025-09-04 15:30:14
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Implementing All-Optical New Reversible Gate using SOA-MZI Architecture
摘要： Reversible circuits have gained a lot of attention lately because of its remarkable property of dissipating lesser power as compared to irreversible circuits due to the fact that they do not lose information. Because of continuing revolution in VLSI technology transistor count and thus power dissipation has increased to such an extent that it has put a limit on packing density and performance of the circuits. To overcome these limits reversible logic has came into picture and various reversible logic gates such as Feynman gate, Fredkin gate, Toffoli gate, Peres gate etc has already been designed in optical domain. Semiconductor optical amplifier (SOA) based mach-Zehnder interferometer (MZI) plays a promising role in this field of ultra fast all-optical information processing because of its advantages like high speed, low power, easy of fabrication and fast switching time. Thus various circuits designed by these basic gates has been analysed in terms of cost parameters and it was seen that optical cost and delay of digital circuits is more than desired, as a result performance of system is rendered. Thus new gates are designed by various researchers that focus on improving cost and thus performance of the system. Studying all these modified gates and the digital circuits implemented in literature, an idea of New All-optical universal reversible gate has been proposed which will further improve the performance of digital circuits. Applications of this gate include the design of full adder, half adder, multiplexer and various other combinational circuits and also 13 standard Boolean expressions can be implemented with improved cost. Simulation of this new gate is done using VPI Photonics software.
关键词： Reversible Gates,Mach Zehnder Interferometer,All-Optical Communication,Semiconductor Optical Amplifiers
更新于2025-09-04 15:30:14
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High Sensitive Directional Twist Sensor Based on a Mach–Zehnder Interferometer
摘要： A new type of Mach–Zehnder interferometer (MZI) is proposed to measure twist and temperature. The sensor contains a pretwisted taper and a ball. The pretwisted taper is made by pretwisted, and then, thermally tapering along a single-mode ?ber, to induce permanent spiral distortion in the ?ber. The experimental results indicate that the sensor has higher twist sensitivity. Twisting the sensor for counterclockwise and clockwise direction, the twist sensitivities of Dip 1584 nm are –0.378 and 0.083 nm/(rad/m), respectively, and the twist sensitivities of Dip 1685 nm are –0.117 and 0.089 nm/(rad/m), respectively. Meanwhile, the twist direction can be determined by the value of the twist sensitivities. The temperature sensitivities of Dip 1584 and Dip 1685 nm are 63 pm/°C and 74 pm/°C, respectively. The feasibility of measuring the torsion and temperature characteristics has been experimentally con?rmed. Thus, the proposed MZI sensor can be used to measure twist and temperature and discriminate twist direction.
关键词： twist,Mach–Zehnder interferometer,temperature,pre-twisted taper
更新于2025-09-04 15:30:14
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Measurement of In-fiber Refractive Index Change Using a Mach-Zehnder Interferometer
摘要： We report, for the first time, the use of a fiber optic Mach-Zehnder interferometer to measure core refractive index changes written by an ultrafast laser irradiation. The core-offset interferometer was constructed by splicing a slightly misaligned stub of standard single mode fiber between lead-in and lead-out optical fibers. When the core refractive index of an in-fiber interferometer is altered, it changes the phase of the core light. Since the phase of light propagating in the cladding (reference arm) remains unchanged, the transmission fringe pattern of the interferometer observes a spectral shift. The spectral shift was used to quantify the effective core refractive index change in a standard single mode fiber. Measurement of effective refractive index changes as high as 0.01356 and as low as 0.000475 are reported in this work.
关键词： effective refractive index change,fiber-optic sensor,ultrafast laser,Mach-Zehnder interferometer,in-fiber refractive index measurement
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) 4TH ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2018 (EGM 2018) - Bandung, Indonesia (27–28 July 2018)] - Optimization of Mach-Zehnder interferometer for application in all-optical reversible gates
摘要： This work is dedicated to optimization of Mach-Zehnder Interferometer (MZI) for reversible gates. The MZI is developed by additional components such as polarization controllers and phase modulators (PM). This gives more paramaters that can be varied in optimizing the MZI. The results indicate good observation especially in varying phase angle of the PM. Since the PM has lower and upper angles, thus both combination are studied with the presence of clock signal. Eliminating unwanted signals is conducted by adjusting the position of polarization and phase delay between the two input signals. Output signals at the transmission and reflection ports are monitored that represent similarity with the truth table of MZI switch.
关键词： polarization controllers,reversible gates,phase modulators,Mach-Zehnder Interferometer,optimization
更新于2025-09-04 15:30:14