G. Eduardo Sandoval-Romero

• Doctor of Engineering
• Researcher at Universidad Nacional Autónoma de México-Instituto de Ciencias Aplicadas y Tecnología

Optical sensors are a promising technology in structural and health monitoring due to their high sensitivity and immunity to electromagnetic interference. Because of their high sensitivity, they can register the responses of buildings to a wide range of motions, including those induced by ambient noise, or detect small structural changes caused by...

In recent years, the importance of reliable displacement detection for structural condition monitoring has grown significantly for applications requiring high-sensitivity devices to meet the diverse needs of various applications, ranging from millimeters to micrometers. This study focuses on fabricating and characterizing three polydimethylsiloxane...

Measurement of displacement, deformation, curvature, and other physical parameters is to great importance for adequate Structural Health Monitoring (SHM) of large surfaces. Fiber Bragg Grating (FBG) sensors have become a focus of research in academia and engineering for structural monitoring applications. This paper presents the study and character...

This work developed, simulated, and characterized a high sensitivity vibration sensor for low-frequency applications. The fiber Bragg grating (FBG) overlapping method was used to demodulate the wavelength shift of the sensing gratings, but only one FBG for each axis was utilized (unlike two FBGs in the common approach), along with another one actin...

The use of the angular spectrum method (ASM) to simulate the reflection of airborne ultrasound beams from a thin membrane separating air from a mixture of air and another gas is examined. The main advantage of this method is its high computing speed and efficiency for practical design calculations, suitable for sensing applications. The implemented...

A system was developed that allows different acoustic parameters to be measured inside the frequency audio range and that can be used in different propagation mediums. A simple configuration of fiber optic sensors based on multimodal interference (MMI) is used, due to the advantages they provide. To perform a spatial and frequency filtering accordi...

A Bragg grating sensor prototype for Structural Monitoring is presented for the measurement of bidirectional displacements (±50 mm) with a single grating, based on curvature sensing with a sensitivity up to 40 pm/mm.

This paper presents the development and analysis of an optical biaxial accelerometer based on fiber Bragg gratings (FBGs) using an enhanced ratiometric interrogation method: Bragg grating overlapping interrogation. Typically, this method requires two FBGs for each sensing axis in the accelerometer. However, the configuration employed in this study...

This paper presents the development and analysis of an optical biaxial accelerometer based on fiber Bragg gratings (FBGs) using an enhanced ratiometric interrogation method: Bragg grating overlapping interrogation. Typically, this method requires two FBGs for each sensing axis in the accelerometer. However, the configuration employed in this study...

Resumen. En este trabajo se presenta la experiencia de Monitoreo Comunitario Participativo (MCP) del agua en una comunidad forestal de la periferia suroeste de la Ciudad de México, realizado durante 2015-2017 por un equipo colaborativo (academia-comunidad). Apoyándose en el marco conceptual de MCP, se desarrollan varias etapas del estudio: i) el mo...

A light scattering instrument has been designed to allow an investigation of the spatial intensity distribution profile, due to the cells within, a liquid solution, in the near forward direction. The cells are illuminated by the light source, a collimated LED, and the light scattered is imaging with a SCMOS camera. By filtering the unscattered ligh...

In this work we investigate an efficient method for calculating the reflected and transmitted acoustic fields from diffracting ultrasound beams incident to a gas/gas interface. The study is motivated by the application to gas sensors of an experimental setup consisting of a 40 kHz acoustic incident beam at oblique angles to an interface separating...

This paper describes a fiber Bragg grating based biaxial accelerometer prototype intended for seismic applications. The work includes the accelerometer structural scheme, optical scheme, sensibility, frequency response and the laser beam deflection method used for calibration. Results of this work show that the device is suitable for seismic measur...

This paper presents a fiber Bragg grating accelerometer prototype for seismic applications, including accelerometer scheme, calibration method and accelerometer resonance frequencies. The acceleration calibration and measurements were obtained from the laser beam deflection method. A series of experiments were carried out and results shows an accel...

The present work shows the design of an instrument to measure the forward extinction and light scattering for a particle monolayer by using a beam stop, which acts as spatial filter.

In this work we present an optical accelerometer based in a cantilever beam attached to a fiber Bragg grating (FBG), which can be applied to the seismic and geological fields. This device main characteristics are a high strain along the FBG and a wide operational frequency range. The accelerometer can be easily modeled as a mass block and a fiber o...

We present and describe a method to demodulate the incoming strain signal from sensors based on fibre Bragg gratings (FBGs). This demodulation is achieved by using a reference FBG with similar characteristics to those of the FBG sensor as a band-pass filter to recover the total power in the detected signal from the shift in the Bragg wavelength cau...

A novel cantilever-type fiber Bragg grating (FBG) mechanical vibration sensor has been proposed with an excellent sensitivity through the use of the mechanical axial property of a suspended optical fiber with two fixed ends, enhancing the sensitivity and the resonant frequency. The experimental results show a resolution of 0.006 g (where ݃ represen...

In the fields of civil engineering and seismology, it is essential to detect and tracking the vibrations, and the fiber Bragg gratings (FBGs) are typically used as sensors to measure vibrations. Where, one of the most popular and detailed approaches to use FBGs as vibration sensors involves the use of cantilever beam designs, which adds a mass to m...

We present a device built in fiber optic capable of detecting acoustic signals in water, using a buzzer as the vibration source, this buzzer operates at a frequency range from 3 kHz to 30 kHz. This device operates under the principle of a Sagnac interferometer, where the acoustic waves emitted by the buzzer are detected as a phase modulation in the...

A hybrid method to obtain nanometric displacements based on interference fringes movement by optical beam deflection is proposed. A proof-of-principle experiment is described as a new method for real-time detection and measurement of small vibrations, experimental results shows an increase in the resolution compared with a simply optical beam defle...

The aquifer recharge area that supplies water to Mexico City is being protected with the implementation of land use restrictions and with the use of payment schemes for maintaining environmental services (PES). In order to assess the effects of PES in the conservation soil area, the chemical and isotopic compositions of water from springs were char...

In this work, we present the experience of implementing of Community Participatory Monitoring scheme (CPM) of water quality in a forest community, located on the periphery of Mexico City. This scheme has driven under the assumption that by using the simple techniques of observation of water resources its can encourage community participation in the...

In this work we present the experimental results of the output spectra of an erbium-doped fiber amplifier when it's coupled with an ytterbium-doped fiber. The use of a superluminescent source in the proposed cascade configuration provides an improvement on 61% on SNR, moreover, in the output signal causes a decreases in spectral width, and filters...

In this work, we present the experience of implementing of Community Participatory Monitoring scheme (CPM) of water quality in a forest community, located on the periphery of Mexico City. This scheme has driven under the assumption that by using the simple techniques of observation of water resources its can encourage community participation in the...

The paper presents an optical fiber Bragg grating (FBG) accelerometer, using a modified cantilever beam design to get the highest possible strain in the FBG and a wide natural frequency. This accelerometer modeled a system composed by a mass mounted at the free end of a cantilever beam, which is also attached to an optic fiber whose length is varie...

The fiber Bragg grating (FBG) accelerometer presented has a modified cantilever beam design, which places a section of the fiber that contains the FBG perpendicular to the cantilever surface, between the tip of the cantilever and the sensor frame. This elongates the FBG axis uniformly in order to get the highest possible strain along the grating, r...

This paper analyses the feasibility of studying the composition of the suspended particles in Mexico City, using for this study, an optical method to choose the most appropriate source of emission, depending on the environmental components. The proper choice of the emission source, allows a more correct assessment of the concentration of pollutants...

The water pollution is a health problem around the world. One of the most common pollutants in water is the Ammonia. Some sensors have been developed for Ammoniac detection even though most of them are not in real time and could be expensive. In this work an Erbium-doped fibre-sensor for Ammonia detection with a mechanical long period fibre grating...

RESUMEN En el presente trabajo se describe la implementación y el funcionamiento de un sensor capaz de realizar mediciones nanométricas de desplazamiento empleando un interferómetro de Michelson en fibra óptica. Para inducir los desplazamientos se utilizó un actuador piezoeléctrico, el cual es excitado con una señal de voltaje alterno. Se determinó...

In this work an Er3+/Yb3+ co-doped all-fiber Mach-Zehnder interferometer that could be suitable for telecomm channel selection, temperature sensing or torsion sensing applications is proposed. The experimental array consists of a 980nm pump laser diode at 350mW output power, a 30cm co-doped fiber segment from our own design, and a mechanicallyinduc...

We present an experimental work of a broadband amplifier centered at 1550 nm using erbium doped fiber and ytterbium doped fiber pumped at 976.8 nm. The preliminary experimental results show that the gain is practically independent of the state of polarization of the pump and the signal. We propose that the Ytterbium doped fiber could be used as an...

Two innovative laser scanning prototypes have been developed at ENEA for diagnostics of large surfaces relevant to monumental cultural heritage. The first, based on amplitude modulation technique in the visible, is a trichromatic (Red /Green /Blue) imaging topologic radar (RGB-ITR) specialized to collect high resolution 3D models. After proper colo...

Commercial Erbium doped silica fibers fabricated through the modified chemical vapor deposition and direct nanoparticle deposition processes where Er3+ concentration is varied in a wide range are characterized by means of analyses of Er3+ fluorescence decay kinetics and nonlinear absorption coefficient at 978-nm pumping. Through theoretical modelin...

We present a simple analysis and comparison between the theoretical and experimental results, in an erbium-doped optical fiber operating in the superluminescent regime. Experimental results for different pumping power levels and fiber length shows, that the theoretical results given for the numerical model could render useful information for predic...

We are presenting experimental work on an erbium-doped fiber operating in the superluminescent regime.Experimental results for different pump power levels and fiber length show that the theoretical and numerical modelcould render useful information for predicting the total output power as a function of fiber doped length and the inputpump power. Th...

Two interferometric systems were built, one in bulk optics and other one in fiber optics for showing the instrumentation stage designed for these devices, supported in a photodetector. This stage has a circuit for amplification, analog filtering and software for single channel data acquisition and digital filtering. Based on the Sagnac effect in bu...

We present a theoretical and experimental work of an erbium-doped fiber optic source operating in the superluminescent regime. Experimental results for different pump power levels and different fiber length show that the theoretical model could render useful information for predicting parameters such as total output power, spectral bandwidth and op...

The objective of this paper is to compare two gyrocompass' schemes for the detection of Earth's true north. These schemes are refered to as dynamic and static methods. We present a model to characterize the sensitivity of each model as a function of the output signal of the sensor element. We use a fiber optic gyroscope (FOG) as the sensor element.

We present a theoretical study of superluminescent optical fiber-sources; in this study we compare the results obtained from an analytic model and the numerical solutions of the rate equations that allow determining the output signal characteristics of such a light source. The characteristics on which we focus our interest are the total optical pow...

This paper is devoted to the development of a prototype optical sensor for observing suspended particles in air at a local level on the territory of México City. The first part of the article discusses an urban atmospheric monitoring system, with special interest in PM2.5 and PM10 particles because of their negative effect on human health and becau...

An interferometric system of volume optics and fiber optic were constructed and proved, showing the instrumentation technique made for these devices, supported in the new technologies of optical detection, amplification, analogical and digital filtrate and single data acquisition. Based on the Sagnac's effect of volume optics and fiber optic, the i...

The objective in this work is to report an analysis of the output characteristics of the basic gyrocompass scheme. This scheme we referred as dynamic. We present the basic principles of gyrocompass operation for earth's true north determination at the dynamic scheme and the causes of the errors and their sources.

We propose and study a novel optoelectronic device for thermal characterization of materials. It is based on monitoring the photothermal deflection of a laser beam within a slab of a thermo-optic material in thermal contact with the sample under study. An optical angle sensor is used to measure the laser deflection providing a simple and experiment...

This paper is devoted to an analysis of the technique of calculating the parameters of a superluminescent fiber radiator (SFR) based on single-mode fiber doped with erbium ions and the optimization of the parameters of the radiator for developing a fiber-optic gyroscope (FOG) with improved accuracy characteristics. The causes of the phase distortio...

In this work an implementation of angular sensor movements is made based on the Sagnac effect, made it in volume optics, using a detection method of the interference lines and its amplified pattern. The new devices of sensing through optical systems, have given a new vision of measurement and instrumentation, guiding to new studies on designs and p...

Most of the investigations that exist about the interferometer of Sagnac in our days, are made through fiber optic, which has the great advantage of having a big area size in very little space wound in a nucleus. The first interferometers of Sagnac, were used for very big angular speeds measures, it didn't have the advances to carry out detections...

Throughout all this paper we are going to analyze one application of the optical beam deflection method (OBDM), the procedure for its development, as well as its ideal implementation to reach measurements of displacements that could be the most accurate and of the smaller scale possible, this condition is essential for the magnitude of the results...

This article describes a simple and fast angle-scanning reflectometer. Approximate formulas for the design and implementation of this type of reflectometer are provided. An experimental device was assembled and its performance was evaluated. The instrument scans the angle of incidence of a laser beam in a range of 5°–10° in less than 0.2 ms. The re...

We propose a simple technique for determining the refractive indices of highly absorbing materials. This method uses two transmittance measurements at oblique incidence. A theoretical analysis of the proposed method is presented. The refractive index of water was experimentally determined with a relative error ranging from 0.12% to 1.3%. We discuss...

Most of the investigations that exist about the interferometer of Sagnac in our days, are made through fiber optic, which has the great advantage of having a big area size in very little space wound in a nucleus. The first interferometers of Sagnac, were used for very big angular speeds measures, it didn't have the advances to carry out detections...

This work proves an experimental model for the detection and location of a radiation punctual source that use plastic scintillating optical fiber (PSF). The principle it based in the conversion of the radiation to light pulses in side of the scintillating material1, arrive times of these light pulses are measuring in the extremes of the fiber. In a...

Throughout all this paper we are going to analyze one application of the optical beam deflection method, the procedure for its development, as well as its ideal implementation to reach measurements of displacements that could be the most accurate and of the smaller scale possible, this condition is essential for the magnitude of the results to eval...

The main objective of this work is to establish which scheme of a gyrocompass is most sensitive in the determination of the true Earth's north; this sensitive depend directly on the output signal characteristics at the sensor element, which on based at the fiber optics gyroscope (FOG) of the phase type; exist two basic scheme's, they're at dependen...

The objective of this work is to establish the dependence of characteristics of the fiber optics gyrocompass with respect to the parameters of the superluminescent emission source based on doped optical fiber with rare earth elements, Superluminescent fiber source (SFS), argument the pumping rate election of the SFS to obtain characteristics limits...

We carry out a detailed analysis of angle-sensitive devices based on the critical-angle effect. We consider their use in measuring small angular deflections of a laser beam. We establish the diffraction limit to the sensitivity for optical-angle sensors based on reflection and transmission of a laser beam. We find that this limit is identical to th...

We present a new all-optical fiber-referencing scheme for intensity-modulated sensors. It consists of a closed loop traversed by sensing and reference optical signals in opposite directions. With the proposed scheme the noise induced by power fluctuations of the optical source and mechanical perturbations can be greatly reduced. We experimentally d...

We propose and study a novel optoelectronic device for thermal characterization of materials. It is based on monitoring the photothermal deflection of a laser beam within a slab of a thermo-optic material in thermal contact with the material under study. An optical angle sensor is used to measure the laser deflection providing a simple and compact...

We propose and study a novel optoelectronic device for thermal characterization of materials. It is based on monitoring the photothermal deflection of a laser beam within a slab of a thermo-optic material in thermal contact with the material under study. An optical angle sensor is used to measure the laser deflection providing a simple and compact...

We present a theoretical study of an erbium-doped optical fiber operating in the superluminescent regime. Experimental results for different pump power levels and fiber length show that the theoretical model could render useful information for predicting parameters such as total output power, spectral bandwidth and optimum fiber length to achieve t...

We report an all-fiber referencing scheme for intensity-modulated fiber optic sensors capable of canceling the noise induced due to random perturbations along the fiber optic links and source power fluctuations. We describe the proposed scheme and present experimental results showing its feasibility. We provide general guidelines for its proper use...

The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the superluminiscent emission source based on doped optical fiber with rare earth elements (Superluminiscent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristi...

The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the superluminiscent emission source based on doped optical fiber with rare earth elements (Superluminiscent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristi...

In this paper, we study a simple angle-sensitive detector for sensing optical beam deflections. This type of device is sought to replace position sensitive detectors commonly used with optical beam deflection techniques in a variety of applications. The main advantage is that the sensitivity is independent of the distance from the deflection point...