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Optical Fiber Sensor for High Sensitivity Molecule Sensing

A low-cost sensor based on evanescent light coupling approach

Published: 9th February 2022
Optical Fiber Sensor for High Sensitivity Molecule Sensing


Molecule sensing is important in many fields. In the field of medicine, biomarkers are used to detect early signs of the disease and to develop personalized treatment to prevent the spread of disease and improve health outcomes. In the field of environmental monitoring, traces of heavy metals and organic contaminants are being monitored in lakes, rivers and oceans to protect marine life and ensure drinking water quality. In the oil and gas industry, critical gases such as hydrogen sulfide and methane are being monitored to ensure environmental safety and mitigate corrosion-related damage on structures. These applications require high sensitivity sensing of molecules. Current approaches for molecule sensing have trade-off between accuracy and cost. For example, the fluorescent labeling method is relatively cheap but is prone to false positives. Further, other sensing methods may require samples with high concentration of target molecules to facilitate the testing. Hence, there is a need for low-cost and sensitive molecule sensing solutions that provide accurate results across a wide range of molecule concentration.

Technology Overview

Researchers at the University of Victoria have developed and patented a low-cost optical sensor that works based on evanescent light coupling approach (Figure 1). A pair of optical fibers, comprising a hollow core fiber and a regular fiber, are fused together to form a fiber coupler. Light from a laser source is allowed to propagate on the regular fiber, while the analyte (liquid or gas) is allowed to pass through the hollow core fiber. The fused section in the fiber coupler allows for the light to interact with the analyte. The presence of the target molecule in the analyte can be determined spectrally using Raman emission spectroscopy. Machine learning-based spectral analysis can be employed to accurately identify the molecule.


  • Cost efficient
  • High level of sensitivity
  • Works on wide range of concentrations
  • Works for both labelling-based and label-free detection applications
  • Employs machine learning-based spectral analysis for molecule identification
  • Can be miniaturized to form a portable sensor


  • Molecule detection in liquid and gas


IP Status
  • Patented
  • Licensing
  • Development partner
  • Commercial partner