Fiber Optic Chemical Sensor

INO has developed a novel fiber optic chemical sensor technology based on ion-selective membranes. This sensor relies on the membrane’s absorption spectrum, which depends on the concentration of a target ion. The membrane is used as the cladding when deposited on a multimode fiber, which guides the signal. The uniqueness of this technology comes from the fact that the concentration of ions in the solution is monitored via evanescent wave spectroscopy. This configuration allows concentration measurements in colored or even opaque solutions, since the light propagating in the core only interrogates the membrane and never “sees” the medium under testing. Moreover, the membrane composition can be adjusted to detect different ions.

Our ion-selective fiber technology is available for technology transfer.

Our expertise: Fiber optic chemical sensors

  • Patented design to optically interrogate the ion-selective fiber cladding

  • Spectral analysis methods for calculating ion concentrations

  • Custom-tailored membrane composition to

    • improve sensor lifetime

    • adjust sensor pH range

    • adjust sensor sensitivity

  • Insensitivity to electromagnetic interference

  • Measurements in opaque solutions

  • Fast response time

  • Low-cost disposable probe, no recalibration required

  • Custom-tailored system for multi-ion or multi-site detection

Our strength:

By combining chemical membrane spectroscopy expertise with our extensive optical system design and development know-how, we can adapt the platform to specific client applications and requirements.

Fields of application:

  • Water monitoring 

  • Process monitoring 

  • Clinical labs 

  • Agrifood

  • Pulp and paper 

  • Chemically or physically aggressive media


The actual membrane is composed of a plasticized PVC lipophilic matrix incorporating a pH sensitive dye, some ionic sites, and an ionophore selective to a particular ion. The membrane is thus selective to the target ion present in an aqueous solution. The ionophore, bound to the specific ion, will cause the dye to release a proton and change its absorption spectrum. This spectral change is then measured and correlated to the target ion concentration. The membrane, constituted with the same basic components, can be rendered sensitive to a given application. Several ion-selective membranes have already been developed (Na+, Ca2+), and the ion-selective fiber (ISF) platform is compatible with multi-ion detection.


Some achievements

These projects are custom-tailored to client needs.
What are your needs? Contact us.

Available technology transfers

You have a project in mind? Talk with our specialists.

You have a project in mind? Talk with our specialists.

Contact us


You will receive a confirmation email including your request, for your track record.