Author: José Javier Sánchez Mondragón

A Highly Sensitive Fiber Optic Sensor Based on Two-Core Fiber for Refractive Index Measurement

José Javier Sánchez Mondragón (2013)

A simple and compact fiber optic sensor based on a two-core fiber is demonstrated for high-performance measurements of refractive indices (RI) of liquids. In order to demonstrate the suitability of the proposed sensor to perform high-sensitivity sensing in a variety of applications, the sensor has been used to measure the RI of binary liquid mixtures. Such measurements can accurately determine the salinity of salt water solutions, and detect the water content of adulterated alcoholic beverages. The largest sensitivity of the RI sensor that has been experimentally demonstrated is 3,119 nm per Refractive Index Units (RIU) for the RI range from 1.3160 to 1.3943. On the other hand, our results suggest that the sensitivity can be enhanced up to 3485.67 nm/RIU approximately for the same RI range.


Fiber optic sensor Refractive index sensor Two-core fiber CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

Fiber Optic Sensor for High-Sensitivity Salinity Measurement

José Javier Sánchez Mondragón (2013)

A highly sensitive salinity sensor based on a two-core optical fiber is demonstrated for both high- and low-concentration regimes. Salinity of several aqueous solutions is measured in the ranges from 0 to 5 mol/L and from 0 to 1 mol/L with sensitivities of 14.0086 and 12.0484 nm/(mol/L), respectively. The achieved sensitivity is ∼19 times higher than that recently reported for polymide-coated photonic crystal fibers.


Fiber optics sensor In-fiber directional coupler Salinity sensor CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

All-fiber multimode interference micro-displacement sensor

José Javier Sánchez Mondragón (2013)

We report an all-fiber micro-displacement sensor based on multimode interference (MMI) effects. The micro-displacement sensor consists of a segment of No-Core multimode fiber (MMF) with one end spliced to a segment of single mode fiber (SMF) which acts as the input. The other end of the MMF and another SMF are inserted into a capillary ferrule filled with index matching liquid. Since the refractive index of the liquid is higher than that of the ferrule, a liquid MMF with a diameter of 125 μm is formed between the fibers inside the ferrule. When the fibers are separated this effectively increases the length of the MMF. Since the peak wavelength response of MMI devices is very sensitive to changes in the MMF’s length, this can be used to detect micro-displacements. By measuring spectral changes we have obtained a sensing range of 3 mm with a sensitivity of 25 nm mm−1 and a resolution of 20 μm. The sensor can also be used to monitor small displacements by using a single wavelength to interrogate the transmission of the MMI device close to the resonance peak. Under this latter regime we were able to obtain a sensitivity of 7000 mV mm−1 and a sensing range of 100 μm, with a resolution up to 1 μm. The simplicity and versatility of the sensor make it very suitable for many diverse applications.


Sensors MMI Multimode interference Multimode fiber Fiber sensor Micro-displacement CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

Fiber Optic Pressure Sensor of 0–0.36 psi by Multimode Interference Technique

José Javier Sánchez Mondragón VICTOR IVAN RUIZ PEREZ (2013)

This paper presents the design, development and tests made to a fiber optic pressure sensor using the multimodal interference methodology (MMI) thus, we propose an alternative sensor to the ones available which are limited by high robust environments where the use of them is a potential hazard (explosive gases, corrosion and even electromagnetic fields). The range of work for this sensor is 0 to 0.36 psi, the arrangement used is formed by a laser diode, a sensing element, an electronic amplifying circuit, a data acquisition board and a computer. The sensing element used is a SMS fiber optic structure (singlemode–multimode–singlemode, where a multimode fiber is embedded between two singlemode fibers) placed within the contact surface (diaphragm) made of a polymeric material; the body of the sensor was made of nylamid. The bending produced in the diaphragm by the pressure inside the body of the sensor generates changes in the transmitted power response carried inside the fiber.

Se presenta el diseño, fabricación y pruebas realizadas a un sensor de presión de fibra óptica utilizando la metodología de interferencia multimodal (MMI), proponiendo así un sensor alternativo a los sensores existentes los cuales son limitados por ambientes de alto riesgo donde su uso es un peligro latente (gases explosivos, corrosión e inclusive campos electromagnéticos). El rango de trabajo para este sensor es de 0 a 0.36 psi, el arreglo utilizado está conformado de un diodo láser, elemento de sensado, circuito electrónico amplificador, tarjeta de adquisición de datos y una computadora. Como elemento de sensado se utilizó una fibra óptica SMS (por sus siglas en inglés singlemode–multimode–singlemode, formada por una fibra multimodo unida entre dos secciones de fibra monomodo) colocada dentro de una superficie de contacto (diafragma) hecha de material polimérico, el cuerpo del sensor está construido de nylamid. La deflexión producida en el diafragma por la presión dentro del cuerpo del sensor generará cambios en la respuesta de potencia transmitida a través de la fibra.



Design of a pressure sensor of 0–7 bar in fiber optic using MMI methodology

VICTOR IVAN RUIZ PEREZ José Javier Sánchez Mondragón (2013)

This research shows the possibility of measuring pressure in the range of 0–7 bar and the comparison against 2 commercial sensors. The technique used is based on the multimodal interference in a fiber optic singlemode–multimode–singlemode (SMS) to 1550 nm. The fiber optic is mounted on a plate of stainless steel AISI 316, where the bending of the plate will generate a curvature on the part of the multimodal fiber generating a decoupling of modes and this generates a low intensity to the output of the system.