Optical Mach-Zehnder Interferometer Research Articles

Gravitational wave detection by hollow-core fiber-optics Mach-Zehnder interferometry

Recent advances in the field of very long distance optical communication suggest the adoption of the advanced technology based on Hollow Core Nested Anti- resonant Nodeless Fiber (HC-NANF) within the endeavour of Gravitational Wave detection using a Mach-Zehnder optical interferometer (MZ-IF). The proposal, consisting of a summary project of the device emphasizes the favorable properties of (MZ- IF) in comparison with Michelson Interferometer (M-IF) currently in operation. The key feature of the proposed method consists of the use of a couple of “fibrated” metallic antennas enfolded by a very large number (h x 7,7 x 104 with h= 1,2,3 etc.) of coiled rings or of straight sections of the (HC-NANF) fiber. This amounts to a corresponding fiber length: L (K) = h x 1500 Km. The relevant properties of the device are noise reduction, absence of critical optical mirror alignment in a noisy environment, reduced spatial extension of the apparatus, exploration of the entire sky scenario by freely orientable antennas, a substantial cost reduction of the apparatus. The remarkable properties of (HC-NANF), invented by F. Poletti in 2013 are currently investigated by his group at the University of Southampton, UK.

Hilbert transform for modulation of interference fringes of liquid substances

The demodulation of interferometric signals presents a challenge in the study of object, especially when working in environments with disturbances, instability or noise. This document presents a procedure to demodulate a pair of highly noisy interferograms obtained with a fiber optic Mach Zehnder interferometer, the procedure is based on using the reconfiguration of the interference fringes as a result of Hilbert Transform. The method shown is fast, it does not present susceptibilities at high frequencies, it avoids demodulating interference patterns of closed fringes and with little carrier signal, in addition, it allows to verify the mathematical equivalence of the spectral analysis using Fourier Transform. As an application model, samples of liquid substances were used, where it was possible to know changes between substances according to their density

Optimization of nanoparticles for application in optical sensors

This study explored the influence of crystallite size on a nanoparticle-coated fiber optic Mach-Zehnder Interferometer (MZI). The primary aim was to enhance the magnetic properties of the nanoparticles for application in fiber optic sensors designed for magnetic field sensitivity. The motion of the nanoparticles within the magnetic field induced alterations in the sensor's transmission, creating an imbalance in the optical signals between the interferometer arms. Nickel ferrites (NiFe2O4) with average crystallite sizes of 3.3 nm, 51.9 nm, and 74.3 nm were used. The nanoparticles were identified by X-ray diffraction, VSM magnetic measurements, and Mössbauer spectroscopy. Structural parameters obtained from X-ray diffraction underwent refinement using the Rietveld method, and the Scherrer equation was applied to determine the average crystallite size. Magnetic sensor performance was assessed for sensitivity, precision, and accuracy for different nanoparticle sizes. The relationship between output power and applied magnetic field exhibited linearity between 87.6% and 99.2%. Sensitivity varied from 1.65 dB/Oe to 3.17 dB/Oe for different particle sizes, indicating an increase in sensitivity with nanoparticle magnetization. This study establishes a correlation between crystallite size and nanoparticle magnetization, enhancing sensor responsiveness. This optimization facilitates the development of tailored electric current and magnetic field sensors, considering nanoparticle size and their distinctive magnetic properties. Although the primary focus was on the optical sensor, a comprehensive nanoparticle characterization was crucial as it directly influenced sensor performance.

Characterization of Mass Transfer within the Crystal-Solution Boundary Layer of l-Alanine {120} Faces Using Laser Interferometry during Growth and Dissolution.

Crystallization and dissolution are important processes to consider in drug development as well as many other industrial processes. Many current growth and dissolution models are based on bulk solution properties and do not implicitly consider concentration variation close to the crystal surface-solution interface and how this is mediated by solute diffusive mass transfer. Solution boundary layer thickness and concentration distribution, for the {120} crystal habit face of single crystals of l-alanine in saturated aqueous solutions during both growth and dissolution processes, is measured as a function of super/undersaturation using a Mach-Zehnder optical interferometer system. Further analysis allows determination of the diffusion coefficient and mass flux within the boundary layer as well as whether the processes are controlled by mass transfer or crystal interfacial kinetics. The measurement of this study revealed that the {120} face was not saturated at its surface during growth or dissolution meaning both processes were somewhat limited by their crystal interfacial kinetics. Growth was limited by crystal interfacial kinetics at all supersaturations to the same degree, whereas dissolution had a mixed dependency on crystal interfacial kinetics and mass transfer at lower undersaturations becoming more limited by mass transfer at higher undersaturations. Boundary layer thickness increased with super/undersaturation but to a lesser degree than the increase in the concentration difference between the crystal surface and bulk solution leading to a higher mass flux of solute molecules through the boundary layer. At the same relative super/undersaturation mass flux of solute molecules was faster during dissolution which was concurrent with its increased surface to bulk solution concentration difference and boundary layer thickness.

Quantum coherence versus interferometric visibility in a biased Mach–Zehnder interferometer

The double-slit interferometer and the Mach-Zehnder interferometer (MZI) with balanced beam splitters are prototypical setups for investigating the quantum wave-particle duality. These setups induced a quantitative association of interferometric visibility (IVI) with the wave aspect of a single quantum system (WAQ). Recently, it was realized that quantum coherence (QC) can be better suited than IVI for quantifying the WAQ in complementarity relations. In this article, we investigate a MZI with biased beam splitters both in the input and the output, and we show that in some cases the IVI is not adequate to quantify the WAQ since it does not reflect the behavior of the quantum coherence, even for a bi-dimensional closed quantum system. Using IBM quantum computers, we experimentally verify our theoretical findings by doing a full quantum simulation of the optical MZI with biased beam splitters.

Group delay manipulation in a passive microwave-photonic fiber optic Mach-Zehnder interferometer.

Conventional slow and fast light (SFL) systems are based on active or nonlinear media or photonic band-gap systems. Radio-frequency (RF) interferometric systems were recently explored for sustaining fast and slow light, owing to their simple structures and passive operation. This Letter introduces a simple, effective, and efficient SFL system based on a linear and passive microwave-photonic (MWP) fiber optic Mach-Zehnder interferometer (MZI). By optically tuning the light transmission ratio of the two fiber beams of the MZI (i.e., the optical carrier), we demonstrate that both delay and advancement of a RF signal (i.e., the envelope signal) can be realized. The magnitude of the signal group delay can also be adjusted using the optical tuning method. Therefore, high-degree manipulation of signal group delay can be achieved using the proposed MWP fiber optic MZI system.

High-Sensitivity Liquid Level Sensor Based on the Balloon-Shaped Fiber Optic MZI

We demonstrated a high-sensitivity liquid level sensor based on the balloon-shaped fiber Mach-Zehnder interferometer (MZI). To make an optical fiber MZI sensor, a bare single mode fiber (SMF) is bent into a balloon shape. The sensor is attached to a stiff support and linked to a buoyancy ball floating on the liquid surface via a thin thread. The change in liquid level will bend the fiber and lead to a wavelength shift of transmission spectrum. This is a novel method of measuring liquid levels. We comprehensively studied the sensing performance of the sensor, and applied the ridge regression algorithm to optimize the fitting results of the experimental data. The maximum sensitivity of liquid level and temperature are 5.245 nm/mm and 40.3 pm/°C respectively, and the sensor has a low temperature cross-sensitivity of 0.00768 mm/°C. Furthermore, the sensor has the advantages of real-time response, convenient manufacture, low cost and high reliability, which broadens the application area of balloon-shaped MZI and makes it appropriate for liquid level sensing.

A Partial Discharge Detection System for XLPE Cable Terminals and Acoustic Wave Sensing Characteristics Based on Fiber Optic Mach-Zehnder Interferometer

Monitoring the cable terminal’s partial discharge (PD) is of great significance to ensure the cable line’s safe and stable operation. To improve the anti-interference ability and real-time performance of partial discharge detection, this paper develops a partial discharge Mach-Zehnder interferometer (MZI) detection system for cross-linked polyethylene (XLPE) cable terminals. The optical fiber is implanted into the 10 kV XLPE cable terminal, and airgap defects of different volumes are set in the main insulation. The optical fiber inside the cable terminal serves as the sensing head of the MZI signal arm. PD test was carried out on the samples, and the test results of fiber optic MZI and high-frequency current transformer (HFCT) were compared and analyzed. The results showed that the 10 kV XLPE cable terminal does not produce PD due to optical fiber implantation. The partial discharge of 196 pC can be recognized by the fiber optic MZI for the cylindrical airgap defect sample with a base radius of 1.5 mm and a height of 3 mm. For the cylindrical airgap defect sample with a base radius of 1.5 mm and a height of 1 mm, the sensitivity of partial discharge detection by fiber optic MZI is higher than that by HFCT. The sensitivity of partial discharge inception voltage (PDIV) detection is increased by 27.5%.

Determination of temperature and strain by a compact optical fiber Mach-Zehnder interferometer (MZI) composed of a single-mode fiber (SMF), seven core fiber (SCF), and multimode fiber (MMF) with a fiber Bragg grating (FBG)

A compact optical fiber Mach-Zehnder interferometer (MZI) sensor is reported for temperature and strain. The MZI sensor consists of a single-mode fiber (SMF), a seven core fiber (SCF) and a multimode fiber (MMF) with a fiber Bragg grating (FBG). The intensity distribution of the sensor is calculated by the beam propagation method. The light is coupled from the lead-in SMF into the SCF through the MMF. The highest transmission efficiency was obtained when the length of MMF is 2 mm with a diameter of 105 μm. The temperature sensitivity is up to 55.06 pm/°C from 130 °C to 250 °C, while the maximum extinction ratio was 27.4 dB. The measurements were divided into two intervals to address cross coupling to provide sensitive temperature and strain measurements.

Microfiber thermo-optic modulator based on reduced graphene oxide film

We investigate a modulator based on reduced graphene oxide (RGO) thermal conductive film and in-fiber optical Mach–Zehnder interferometer (MZI). MZI is fabricated by stretching single-mode fiber by high-temperature heating. The cone region of MZI is coated with RGO thermal conductive film, which is heated by electrothermal effect through silver electrodes. The heating of the heat-conducting film changes the effective refractive index of the optical fiber, which leads to a phase difference of MZI. Five channels are formed across C- and L-bands. The maximum shift of interference peak spectrum is more than 2 nm. Meanwhile, the device has a modulation phase shift with a nearly linear slope of 0.007 π / mW near the wavelength of 1555 nm, and an extinction ratio of 4 dB for optical switching with a rise (fall) time of 80 ms (70 ms) is achieved. The high-density integration and all-fiber structure enable the proposed device to have great potential in the miniaturization of optical devices.

Design of optical Mach–Zehnder interferometer phase shifter in silicon-on-insulator

A passive TE mode phase shifter-based compact structure of optical Mach–Zehnder interferometer (MZI) using silicon-on-insulator (SOI) platform is demonstrated by using BPM simulations. Insertion loss was found, that is 9 dB for 3 $$\mu $$ m width, 16 dB for 1.55 $$\mu $$ m wavelength, 0.9 dB for 2000 $$\mu $$ m path length (arms), and 15 dB for 0.0055 index differences between the core and the cladding of SOI of the designed device. The Mach–Zehnder interferometer attains good phase shifts by changing the path lengths (arm) with TE mode polarisation.

CL-TWE Mach–Zehnder electro-optic modulator based on InP-MQW optical waveguides

In this Letter, we reported the preliminary results of an integrating periodically capacitive-loaded traveling wave electrode (CL-TWE) Mach–Zehnder modulator (MZM) based on InP-based multiple quantum well (MQW) optical waveguides. The device configuration mainly includes an optical Mach–Zehnder interferometer, a direct current electrode, two phase electrodes, and a CL-TWE consisting of a U electrode and an I electrode. The modulator was fabricated on a 3 in. InP epitaxial wafer by standard photolithography, inductively coupled plasma dry etching, wet etching, electroplating, etc. Measurement results show that the MZM exhibits a 3 dB electro-optic bandwidth of about 31 GHz, a Vπ of 3 V, and an extinction ratio of about 20 dB.

Measurement of In-Fiber Refractive Index Change Using a Mach–Zehnder Interferometer

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 the 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. Measurements of effective refractive index changes as high as 0.01356 and as low as 0.000475 are reported in this letter.

Design and Development of Mach Zehnder Interferometer based Optical Sensors to Detection of Arsenic compound in Drinking Water

Water, the inevitable need of any individual, must be monitored. Detection of the arsenic chemical present in water leads to contagious diseases. The legacy makes people difficult to survive. The consequences are cancer, other diseases. Employing photonic crystal waveguide with the rally round of mach Zehnder interferometer, it is feasible to correctly compute arsenic compound level in water. MZI sensor has many compensation, diminutive, least use of instrumentation, and ready to be used with CMOS technology. Follows in the paper, arsenic compound level of wavelength range of 1530–1565 nm is analyzed and detected. Experiential program from the band arrangement that for minute change in refractive index is accounted, subsequently logical shift in the frequency and amplitude will be evident enlarging mach Zehnder interferometer will behave as a sensor. Thus projected alternate included optical Mach Zehnder Interferometer (MZI), composed of graded index channel waveguide that can be frequently used as chemical and biological sensor in this manuscript. This dissertation describes how the MZI operates two arms predominantly to conquer the industrial challenges. Manuscript represents test data, graph and results that exemplify the performance of whole system.

Use of 3×3 Coupler in the Fiber Optic Strainmeter Based on Mach-Zehnder Interferometer

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Integrated Optical Mach-Zehnder Interferometer Based on Organic-Inorganic Hybrids for Photonics-on-a-Chip Biosensing Applications.

The development of portable low-cost integrated optics-based biosensors for photonics-on-a-chip devices for real-time diagnosis are of great interest, offering significant advantages over current analytical methods. We report the fabrication and characterization of an optical sensor based on a Mach-Zehnder interferometer to monitor the growing concentration of bacteria in a liquid medium. The device pattern was imprinted on transparent self-patternable organic-inorganic di-ureasil hybrid films by direct UV-laser, reducing the complexity and cost production compared with lithographic techniques or three-dimensional (3D) patterning using femtosecond lasers. The sensor performance was evaluated using, as an illustrative example, E. coli cell growth in an aqueous medium. The measured sensitivity (2 × 10−4 RIU) and limit of detection (LOD = 2 × 10−4) are among the best values known for low-refractive index contrast sensors. Furthermore, the di-ureasil hybrid used to produce this biosensor has additional advantages, such as mechanical flexibility, thermal stability, and low insertion losses due to fiber-device refractive index mismatch (~1.49). Therefore, the proposed sensor constitutes a direct, compact, fast, and cost-effective solution for monitoring the concentration of lived-cells.

Silicon Photonics towards Disaggregation of Resources in Data Centers

In this paper, we demonstrate two subsystems based on Silicon Photonics, towards meeting the network requirements imposed by disaggregation of resources in Data Centers. The first one utilizes a 4 × 4 Silicon photonics switching matrix, employing Mach Zehnder Interferometers (MZIs) with Electro-Optical phase shifters, directly controlled by a high speed Field Programmable Gate Array (FPGA) board for the successful implementation of a Bloom-Filter (BF)-label forwarding scheme. The FPGA is responsible for extracting the BF-label from the incoming optical packets, carrying out the BF-based forwarding function, determining the appropriate switching state and generating the corresponding control signals towards conveying incoming packets to the desired output port of the matrix. The BF-label based packet forwarding scheme allows rapid reconfiguration of the optical switch, while at the same time reduces the memory requirements of the node’s lookup table. Successful operation for 10 Gb/s data packets is reported for a 1 × 4 routing layout. The second subsystem utilizes three integrated spiral waveguides, with record-high 2.6 ns/mm2, delay versus footprint efficiency, along with two Semiconductor Optical Amplifier Mach-Zehnder Interferometer (SOA-MZI) wavelength converters, to construct a variable optical buffer and a Time Slot Interchange module. Error-free on-chip variable delay buffering from 6.5 ns up to 17.2 ns and successful timeslot interchanging for 10 Gb/s optical packets are presented.

Integrated optical Mach-Zehnder interferometer-based defect detection using a laser-generated ultrasonic guided wave.

The laser-based transmitter used in this Letter is composed of an integrated optical Mach-Zehnder interferometer, which was first used in fault diagnosis. With the help of the effective signal processing method and laser-based integrated optical Mach-Zehnder (IOMZ) system, the location of the defect in an aluminum plate can be successfully determined. Moreover, a comparison study is conducted to investigate the effectiveness of both the conventional laser spot source and the IOMZ interferometer-based laser source. The results indicate that the IOMZ interferometer-based method can be very useful to the nondestructive testing research field. The potential for industrial applications is also significant, especially for the health monitoring and integrity inspection of metal plates.

High temperature high sensitivity Mach-Zehnder interferometer based on waist-enlarged fiber bitapers

An optical Mach-Zehnder interferometer (MZI) composed of a short section of thin-core fiber (TCF) which inserted into a standard single-mode fiber (SMF) with two waist-enlarged bitapers was proposed for high temperature measurement. MZIs with different lengths were fabricated, and the relationship between length and interference period was studied. The fast Fourier transform (FFT) method was used to determine the transmitted spectra of MZIs, and the results indicate that LP01 and LP02 modes are the main modes. The MZI has a high temperature sensitivity of 0.087nm/°C with a good linearity of 99.8% from 30 to 1000°C. Because it has advantages of compact size, easy fabrication, high sensitivity, high mechanical strength and wide sensing range, the MZI can be used for high sensitivity temperature measurement.

Ultra-compact all-in-fiber-core Mach-Zehnder interferometer.

Optical Mach-Zehnder interferometers (MZIs) are useful components in a variety of optical applications, including optical modulation; signal processing; and physical, chemical, and biological sensing. We introduce here a novel, assembly-free all-in-fiber-core MZI, which is directly written with a femtosecond laser. By introducing a positive refractive index-modified zone in half of the fiber core, the original single-mode fiber section is converted into a few-mode fiber section, where a strong coupling between the two lowest-order guided modes is generated, resulting in a well-defined interference spectrum in transmission. This device promises many significant advantages over existing approaches such as ease of fabrication, stability, small insertion loss, robustness extremely broad operating bandwidth, and precise and controllable cavity lengths. These advantages make this device strikingly attractive with the potential for extensive adoption in fiber communications, signal processing, sensors, and laser wavelength control.