Interferometer and sensor based on bimodal optical waveguides, and detection method

Sensing method comprising the following steps:

• (a) defining a sensor plate (21, 31, 41, 51) in a specific area of a bimodal waveguide (10, 20, 20′, 30, 40) of an optical waveguide interferometer (15, 25, 35, 45);
• (b) placing a chemical, biological or physical stimulus in said sensor plate (21, 31, 41, 51);
• (c) introducing or causing changes in said chemical, biological or physical stimulus placed in said sensor plate (21, 31, 41, 51);
• (d) coupling a zero-order mode and another first-order mode of electromagnetic radiation into said bimodal waveguide (10, 20, 20′, 30, 40), in such a way that when both modes travel through the sensor plate (21, 31, 41, 51) defined in the bimodal waveguide (10, 20, 20′, 30, 40), they suffer a phase delay which is dependent on the changes in said chemical, biological or physical stimulus;
• (e) at the output of said bimodal waveguide (10, 20, 20′, 30, 40), measuring the response of said zero-order mode relative to the response of said first-order mode;
• and
• (f) relating said relative response of both modes to the changes in the chemical, biological or physical stimulus.