Smartphone Plastic Optical Fiber Sensors

Telehealth is quickly becoming an essential tool in delivering medical care. It can easily be used to monitor the states of patients who are located at remote locations away from hospitals. For example, breathing rate is one of important physiological parameters requiring monitoring, since it can be used in the diagnosis of respiratory diseases. However, the tools of remote monitoring have to be cheap and easy in use. These requirements can be satisfied by smartphone sensor based on plastic optical fiber (POF). The proposed solution is an all-fiber sensor where the flashlight acts as a light source and the camera acts as a photodetector. First of all, smartphones have become ubiquitous. POF, on the other hand, is not expensive. Hence, the proposed combination can be a cost-effective solution for implementing telehealth. In the work, the technique of intensity modulation in POF is adapted for sensing breathing rate. The measurements are analyzed in both time and frequency domains. In addition, multiplexing is also a promising direction for conducting sensing in optical fibers, since it can be used to measure multiple parameters. The possibility of implementing it in POF will be considered as well

Design of a smartphone plastic optical fiber chemical sensor for hydrogen sulfide detection

We present a low-cost, handheld plastic optical fiber (POF) sensor for hydrogen sulfide (H2S) detection integrated onto a smartphone. The sensor uses smartphone flashlight as a source and camera as a pixel-based intensity detector. The POF is interconnected to the smartphone with a 3-D-printed connector on both source/detector sides. The sensing mechanism is embedded in the fiber link, making the system an all-fiber smartphone architecture. A mobile application handles data acquisition on the Android operative system. The sensor is functionalized for H2S detection through silver deposition on the POF outer surface. Experiments demonstrate the feasibility of the sensor system as the presence of H2S is successfully measured through an increase of optical losses through the POF link. This cost-effective, scalable, and compact sensor is promising for application in environmental sensing

Distributed 2D temperature sensing during nanoparticles assisted laser ablation by means of high-scattering fiber sensors

The high demand in effective and minimally invasive cancer treatments, namely thermal ablation, leads to the demand for real-time multi-dimensional thermometry to evaluate the treatment effectiveness, which can be also assisted by the use of nanoparticles. We report the results of 20-nm gold and magnetic iron oxide nanoparticles-assisted laser ablation on a porcine liver phantom. The experimental set-up consisting of high-scattering nanoparticle-doped fibers was operated by means of a scattering–level multiplexing arrangement and interrogated via optical backscattered reflectometry, together with a solid-state laser diode operating at 980 nm. The multiplexed 2-dimensional fiber arrangement based on nanoparticle-doped fibers allowed an accurate superficial thermal map detected in real-time

Investigation of thermal effects of radiofrequency ablation mediated with iron oxide nanoparticles dispersed in agarose and chitosan solvents

Thermal ablation (TA) is known as an alternative therapy to surgery to treat tumors. However, TA-based therapy requires advanced approaches in order to prevent causing damage to healthy tissue around the tumor and selectively target the desired area. Nanoparticles are considered as a promising tool in biomedicine to fulfill these requirements. This study was carried out in order to analyze the effect of iron oxide nanoparticles on the temperature increment during radiofrequency ablation therapy of porcine liver. In addition, this research aimed to experimentally evaluate the impact of two solvents such as agarose and chitosan on the temperature change, when magnetic nanoparticles were dispersed in them. The iron oxide nanoparticles were synthesized by the solvothermal method demonstrating the magnetic properties by acting to the external magnetic field. To increase the local heat superparamagnetic nanoparticles (iron oxide magnetic nanoparticle (IONPs)) of the average size of 20 nm in size and the concentrations from 1 to 10 mg/mL of MNPs with a step size of 1 mg/mL were tested in 10 replicates for each concentration and solvent. Moreover, the temperature changes for dry liver, and 0 mg/mL concentration was checked for calibration and reference purposes. As a sensing system, advanced 16-FBG optical fiber sensors connected to an interrogator were employed allowing the temperature change to be monitored accurately in real time. A maximum temperature of about 142 °C was recorded by a 5 mg/mL concentration of iron oxide nanoparticles dispersed in the agarose solvent

Smartphone Plastic Optical Fiber Sensors

Telehealth is quickly becoming an essential tool in delivering medical care. It can easily be used to monitor the states of patients who are located at remote locations away from hospitals. For example, breathing rate is one of important physiological parameters requiring monitoring, since it can be used in the diagnosis of respiratory diseases. However, the tools of remote monitoring have to be cheap and easy in use. These requirements can be satisfied by smartphone sensor based on plastic optical fiber (POF). The proposed solution is an all-fiber sensor where the flashlight acts as a light source and the camera acts as a photodetector. First of all, smartphones have become ubiquitous. POF, on the other hand, is not expensive. Hence, the proposed combination can be a cost-effective solution for implementing telehealth. In the work, the technique of intensity modulation in POF is adapted for sensing breathing rate. The measurements are analyzed in both time and frequency domains. In addition, multiplexing is also a promising direction for conducting sensing in optical fibers, since it can be used to measure multiple parameters. The possibility of implementing it in POF will be considered as well

Machine Learning Estimation of the Phase at the Fading Points of an OFDR-Based Distributed Sensor

The paper reports a machine learning approach for estimating the phase in a distributed acoustic sensor implemented using optical frequency domain reflectometry, with enhanced robustness at the fading points. A neural network configuration was trained using a simulated set of optical signals that were modeled after the Rayleigh scattering pattern of a perturbed fiber. Firstly, the performance of the network was verified using another set of numerically generated scattering profiles to compare the achieved accuracy levels with the standard homodyne detection method. Then, the proposed method was tested on real experimental measurements, which indicated a detection improvement of at least 5.1 dB with respect to the standard approach

Distributed fiber optic shape sensing with simultaneous interrogation of multiple fibers based on Rayleigh-signature domain multiplexing

: We propose a method for shape sensing that employs Rayleigh-signature domain multiplexing to simultaneously probe the fibers or cores of a shape sensing setup with a single optical frequency-domain reflectometry scan. The technique enables incrementing the measurement speed by a factor equal to the number of multiplexed fibers at the expense of an increased noise floor in accordance with the Cramér-Rao lower bound. Nonetheless, we verify that the shape reconstruction performance of the proposed method is in very good agreement with that of conventional sequential core interrogation