Novel Corrugated Long Period Grating Surface Balloon-Shaped Heterocore-Structured Plastic Optical Fibre Sensor for...

Area of Science:

• Optoelectronics and Photonics
• Biotechnology
• Chemical Sensing

Background:

• Accurate real-time monitoring of ethanol concentration is crucial for optimizing microalgal bioethanol production.
• Existing sensing methods may lack the sensitivity or real-time capabilities required for ultra-low concentration detection in complex biological matrices.

Purpose of the Study:

• To develop and demonstrate a novel plastic optical fibre (POF) sensor for real-time measurement of ultra-low ethanol concentrations.
• To enhance sensor sensitivity and resolution through a unique balloon-shaped heterocore structure and long period grating inscription.
• To validate the sensor's performance in microalgal bioethanol production environments.

Main Methods:

• Fabrication of a heterocore-structured POF sensor by coupling large and small core POF segments.
• Modification of the small core fibre (SCF) sensing region via polishing, long period grating (LPG) inscription, and macro bending into a balloon shape.
• Characterization of the sensor's response to various ethanol-water solutions and real microalgal mixtures, assessing sensitivity, resolution, and limit of detection (LOD).

Main Results:

• The developed sensor demonstrated ultra-high sensitivity (up to 210,632.8 %T/%v/v or 5 × 10^6 %/RIU) and resolution (2 × 10^-4 %v/v or 9.4 × 10^-6 RIU) for ultra-low ethanol concentrations.
• A low limit of detection (LOD) of 4.9 × 10^-4 %v/v (or 2.3 × 10^-5 RIU) was achieved, suitable for real-time bioethanol production monitoring.
• The sensor exhibited rapid response and recovery times when tested with both air and ethanol-microalgae mixtures.

Conclusions:

• The novel LPG inscribed balloon-shaped heterocore-structured POF sensor is a highly sensitive and effective tool for real-time monitoring of ultra-low ethanol concentrations.
• Its ease of fabrication, low cost, and robust performance make it a promising candidate for integration into the bioethanol production industry.
• The sensor's capabilities extend to other applications requiring precise ethanol or refractive index (RI) sensing.