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The purpose of this paper is to provide a detailed review of radiation dosimetry techniques based on optical fibre dosimeters. It presents a comprehensive bibliography of the current research activities in the area.

A range of published work on optical fibre radiation dosimeters are presented, with the merits and limitations discussed. Each radiation dosimetry technique is discussed in turn, providing examples of dosimeters using such techniques reviewed. The main focus is on gamma radiation although other radiation dosimeters are considered.

This paper provides information on the wide range of research activity into radiation dosimeters. The dose ranges of these dosimeters are presented, along with the advantages and disadvantages of different dosimetry techniques.

A comprehensive review of published research in the area of solid radiation dosimetry is presented in this paper. It provides an individual with a review of the various techniques used and most recent research in that field.

The purpose of this paper is to provide a comparative review of intensity‐modulated fiber optic sensors with non‐optical sensors for health monitoring applications, from the current research activities in the area.

A range of published research work in sensor design for four different health monitoring applications, including, lumbar spine bending, upper and lower limb motion tracking, respiration and heart rate monitoring, are presented and discussed in terms of their respective advantages and limitations.

This paper provides information on the various types of sensors applied into the health monitoring area. The sensing techniques of the fiber optic sensor for the stated applications are focused and compared in details to highlight their contributions.

A comparative review of published work is illustrated in an informative table content, to allow a clear idea of the current sensing approaches for health monitoring applications.

This study aims to optimize the structure of gold-sputtered U-shaped plastic fiber sensors.

A group of U-shaped Au-sputtered plastic optical fiber sensing probes with polishing angles of 45°, 90° and 135° is prepared.

The experimental results show that the spectral response and sensitivity of the sensor at 45°polishing angle is twice that of the sensor at 90°.

Due to the limitations of laboratory temperature and equipment, the overall effect has not reached the ideal, but the expected effect has been obvious. Experiments also optimize the sensor.

Optical fiber sensing has always been an indispensable part of various fields.

Sensor optimization is of great help to the progress of technology and the development of science and technology.

The authors have no conflicts of interest to disclose.

The main role of polymer optical fibers is to transmit light or optical signal to a specified spot. In the case of side emitting plastic optical fibers the light leaks out from their surface. This sidelight can be used for creation of optically active textile structures providing opportunities to highlight people and objects without the need for external exposure. Due to the transmission loss, the intensity of radiation emitted in any direction decays exponentially along the fiber axis with increasing distance from the light source. The main aim of this contribution is evaluation of side emitting plastic optical fibers light intensity in dependence on the distance from light source. The special device for measurement of surface and cross section light intensity in various distances from light source was developed. The dependence of surface and cross section light intensity on the distance from light source will be expressed by the exponential type model with attenuation factor as the rate parameter. The influence of the optical fiber type and diameter on the attenuation factor of surface and cross section light intensity will be quantified.

The purpose of this research is to ascertain the feasibility of fabricating polymer optical fibers (POFs) based textile structures by knitting with Polymethylmethacrylate (PMMA) based optical fibers for textile sensor application. It has long been established that by using the principles of physics, POFs have the capability to function as sensors, detecting strain, temperature and other variables. However, POF applications such as strain and pressure sensing using knitting techniques has since not been very successful due to a number of reasons. Commercially available PMMA-based optical fibers tend to be fragile and susceptible to breakages when subjected to stress during the knitting processes. Also light transmitted within these fibers is prone to leakage due to the curvature that results when optical fibers are interlaced or interlooped within fabric structures.

Using Stoll’s multi-gauge CMS 350 HP knitting machine, five fabric structures namely, 1 × 4 float knit structure, tunnel inlay knit structure, 3:1 fleece fabric and 2:1 fleece fabric structure respectively were used to knit sensor samples. The samples were subsequently tested for length of illumination and sensitivity relative to applied pressure.

The results of this preliminary study establish that embedding plastic optical fibers into a knitted structure during the fabric formation process for soft strain sensor application possible. The best illumination performance was recorded for tunnel inlay structure which had an average of 94 cm course length of POF being illuminated. Sensor sensitivity experiments also establish that the relative spectral intensity of the fiber is sensitive to both light and pressure. Problems encountered and recommendations for further research have also been discussed and proffered.

Due to resource limitations, an innovative technique (use of precision weight set) was used to apply pressure to the sensors. Consequently, information regarding the extent of corresponding sensor deformation has not been used in this initial analysis.

Because the fundamental step toward finding a solution to any engineering problem is the acquisition of reliable data, and considering the fact that most of the popular technologies used for soft textile sensors are still bedeviled with the problem of signal instability and noise, the success of this application thus has the tendency to promote the wide spread adoption of POF sensors for smart apparel applications.

As far as research on soft strain sensors is concerned, to the best of the authors’ knowledge, this is the first study to have attempted to knit deformable sensors using commercially available POFs.

This paper aims to propose and demonstrate a simple fiber optic sensor using a tapered plastic multimode fiber as a probe for measurement of calcium nitrate concentrations in de-ionized water.

The working mechanism is based on the observed increment in the transmission of the sensor that is immersed in calcium nitrate solution of higher concentration. The tapering of the plastic fiber is carried out by etching method using acetone, sand paper and de-ionized water.

Tapered fiber with diameter 0.45 mm gives the highest sensitivity of 0.028 mV/% due to better interaction between the evanescent field and the calcium nitrate solution with a good slope linearity of more than 98 per cent for a 1.07 per cent limit of detection in a straight probe arrangement. The use of calcium and nitrate ions within the sensing medium demonstrates the strong dependency of the sensor output trend on the electrolytic nature of the chemical solutions.

Demonstration of tapered plastic multimode fiber sensor probe for measurement electrolytic chemical solutions.

This study aims to analyze the transmission characteristics of a long-period grating (LPG) fabricated on plastic optical fibers (POFs) and its refractive index (RI) sensing.

The geometric optic method is used to analyze the factors affecting the transmission characteristics of an LPG on POFs. The RI sensing performances of unbent LPGs and U-bent LPGs fabricated on POFs with different diameters are evaluated experimentally.

This study shows that the transmission loss caused by LPG strongly depends on the structural parameters of LPG and the environmental RI. For the unbent LPG, the highest RI sensitivity of 1,015%/RI unit (RIU) was obtained in the RI range of 1.33–1.45. For the U-bent LPG without cladding, the highest RI sensitivities of 1,007 and 559%/RIU are obtained in the RI ranges of 1.33–1.40 and 1.40–1.45, respectively.

A geometric optic method is used to analyze the transmission characteristics for an LPG on POFs, and the RI sensing of the LPGs are studied experimentally. The results show the LPG has a good RI sensing performances and is with the features of low-cost, simple structure and easy fabrication.

This paper aims to propose a liquid level sensor with a multi-S-bend plastic optical fiber.

The principle of liquid sensing used is based on the leakage of higher modes out of the fiber and repeated regeneration in the following bend sections. Therefore, a propagation loss was introduced in every bend section of the fiber with the loss depending on the refractive index of the environment.

Therefore, a continue shift in the liquid level can be detected by observing changes in the propagation loss of the fiber. The sensor features compactness and a flexible resolution.

Compared with the exited ones, the sensor has capability of continue liquid measurement and a greater measurement range.

The purpose of this paper is to propose and optimize plastic optical fiber (POF) probe with macro-bending biconical tapered structure for the relative humidity (RH) sensing.

In this study, the principle is the evanescent wave power modulated by the ambient humidity. The probe is fabricated by using fused biconical taper and heat-setting method and then coated with a fluorescent moisture-sensitive film.

The probe’s sensing performance can be optimized by changing the probe’s curvature radius, biconical tapered transition length and taper waist diameter. The result shows that the sensitivity of the probe is up to 1.60 and 3.40 mV/ per cent, respectively, at low humidity (10-45 per cent) and high humidity (45-90 per cent). Also, this probe has good linearity, repeatability, photostability and long-term stability.

The proposed probe can improve the sensitivity and linearity of RH sensing without complex devices, which is necessary for mass production, remote measurement and convenient operation.

POF probe with macro-bending biconical tapered structure is investigated in this paper, which is proved to be effective in improving the sensitivity and linearity.

The purpose of this paper is to demonstrate a simple design of a fiber optic displacement sensor using a multimode plastic fiber coupler based on reflective intensity modulation technique.

The performances of this sensor are investigated by correlating the detector output with different light sources, coupling ratios and various real objects with different reflectivity properties namely aluminum, brass and copper. In contrast to the output profile produced by probes with multiple fibers placed adjacently together, this sensor uses only one fiber for sending and receiving the light and therefore only the back slope exists.

Aluminum exhibit the highest performance among the real objects when coupled with a red He‐Ne laser and a coupling ratio of 50:50 with a sensitivity, linear range, resolution and dynamic range of 1.7 mV/mm, 1.5 mm, 16 μm, and 5.0 mm, respectively.

This is the first demonstration of a fiber optic displacement sensor using fiber coupler probe with successful examination of the correlation between the detector output, variation in coupling ratios and reflectivity properties of the tested real objects.