Optical fiber sensors for glucose concentration measurement: A review

In this work, we review the most important achievements of an INESC TEC long-period-grating-based fiber optic Michelson and Mach–Zehnder configuration modal interferometer with coherence addressing and heterodyne interrogation as a sensing structure for measuring environmental refractive index and temperature. The theory for Long Period Grating (LPG) interferometers and coherence addressing and heterodyne interrogation is presented. To increase the sensitivity to external refractive index and temperature, several LPG interferometers parameters are studied, including order of cladding mode, a reduction of the fiber diameter, different type of fiber, cavity length and the antisymmetric nature of cladding modes.

“…one obtained for the SMF28 fiber (4.2 deg/°C) there is an extra reduction of the sensing head thermal sensitivity by a factor of ~2. 6.…”

Section: Lpg Interferometers Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optical Fiber Interferometers Based on Arc-Induced Long Period Gratings at INESC TEC

Caldas

Rego

2021

“…Fiber optic sensors have drawn considerable interest because of the ability for monitoring the environmental variables such as temperature, stress, relative humidity, RI, etc. [ 1 , 2 , 3 , 4 , 5 ]. Such sensors have been widely applied in physical, chemical, and biological applications due to their unique properties (e.g., micro-size, lightweight, flexible, durable, biocompatibility, corrosion resistance, cost-effective, immune to electromagnetic interference) [ 6 , 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

A Taper-in-Taper Structured Interferometric Optical Fiber Sensor for Cu2+ ion Detection

Gong

Lei

Wang

et al. 2022

Copper ion is closely associated with the ecosystem and human health, and even a little excessive dose in drinking water may result in a range of health problems. However, it remains challenging to produce a highly sensitive, reliable, cost-effective and electromagnetic-interference interference-immune device to detect Cu2+ ion in drinking water. In this paper, a taper-in-taper fiber sensor was fabricated with high sensitivity by mode-mode interference and deposited polyelectrolyte layers for Cu2+ detection. We propose a new structure which forms a secondary taper in the middle of the single-mode fiber through two-arc discharge. Experimental results show that the newly developed fiber sensor possesses a sensitivity of 2741 nm/RIU in refractive index (RI), exhibits 3.7 times sensitivity enhancement when compared with traditional tapered fiber sensors. To apply this sensor in copper ions detection, the results present that when the concentration of Cu2+ is 0–0.1 mM, the sensitivity could reach 78.03 nm/mM. The taper-in-taper fiber sensor exhibits high sensitivity with good stability and mechanical strength which has great potential to be applied in the detection of low Cu2+ ions in some specific environments such as drinking water.

“…Until now, many methods for measuring glucose in blood or in various samples, such as a medium for cell culture, have been suggested, and commercial products have been released based on these [ 1 , 2 , 3 , 4 , 5 ]. One of the representative technical methods for measuring glucose is an electrochemical method based on glucose oxidase (GOD).…”

Section: Introductionmentioning

confidence: 99%

Optical Glucose Sensor Using Pressure Sensitive Paint

Park

2021

A glucose sensor is used as an essential tool for diagnosing and treating diabetic patients and controlling processes during cell culture. Since the development of an electrochemical-based glucose sensor, an optical glucose sensor has been devised to overcome its shortcomings, but this also poses a problem because it requires a complicated manufacturing process. This study aimed to develop an optical glucose sensor film that could be fabricated with a simple process using commercial pressure sensitive paints. The sensor manufacturing technology developed in this work could simplify the complex production process of the existing electrochemical or optical glucose sensors. In addition, a photometric method for glucose concentration analysis was developed using the color image of the sensor. By developing this sensor and analysis technology, the basis for glucose measurement was established that enables two-dimensional, online, and continuous measurement. The proposed sensor showed good linearity at 0–4 mM glucose in an aqueous sample solution, its limit of detection was 0.37 mM, and the response time was 2 min.