Optical interferometric sensor

Optical interferometric sensor, in particular of the Mach-Zender type, presenting a first optical path defining a sensing arm and a second optical path defining a reference arm, said sensor comprising:

• an optical splitter upstream of the first and second optical path configured to split an incoming optical signal equally into the sensing arm and the reference arm and an optical combiner placed downstream of the first and second optical path and configured to recombine said optical signal;
• a first waveguide placed along the first optical path and comprising a substrate and a binding surface;
• said binding surface being functionalized to interact and bind at least one marker of a sample;
• a first optical element placed along the first optical path;
• a second waveguide placed along the second optical path and comprising a substrate identical to the substrate of the first waveguide;
• a second optical element placed along the second optical path, and presenting the same optical response of the first optical element;
• a single microfluidic channel running through the first waveguide and the second waveguide;
• and
• at least one between the first optical element and the second optical element comprises a phase shifter configured to tune the phase of the optical signal in either the sensing arm or the reference arm.