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The use of optical fibers with coupled cores is proposed for sensing applications. The interrogation of coupled-core fiber sensors is simple, fast and inexpensive as the parameter being sensed can be detected as intensity changes.

A fiber optic strain sensor, based on the Vernier effect, was constructed using two parallel MZIs. The strain sensitivity of one MZI was 0.84 pm/µε, using this configuration the sensitivity increased up to 13.00 pm/µε.

The use of two phase shifted supermode interferometers is proposed for precision optical fiber sensing. The advantage of such interferometers for sensing include sensitivity enhancement, easy implementation, simple interrogation, and compactness. Some sensors are demonstrated.

A compact and highly sensitive interferometric vibration sensor fabricated with two segments of asymmetric multicore fiber rotated 180º with respect to each other is presented. The sensor performs well for frequencies below 1 Hz.

We propose and demonstrate an extrinsic Fabry-Perot interferometer build with a strongly coupled multicore fiber. The interferometer can be used for measuring distances or any other parameter that induces changes in the cavity length.

A very sensitive orientation and amplitude discerning vector bending sensor based on asymmetric multicore fiber is demonstrated by combining simultaneous wavelength and light power measurements with a maximum sensitivity of 2720 pm/º and 852 nW/º.

Compact interferometers composed by two slightly different segments of asymmetric multicore fiber fusion spliced and rotated 180º with respect to each other are proposed for sensing applications. Examples and advantages of such interferometers are discussed.

A sensor based on gold nanoparticles immobilized onto an optical fiber facet is shown. The innovation is related to the plasmon resonance energy transfer phenomenon application, demonstrating its usefulness for Cytochrome C detection.

The use of two separated, compact modal interferometers (MIs) with an adequate phase shift is proposed for precision optical fiber sensing. The output spectrum of interferometers with such features is a well-defined peak. Changes in the wavelength position or amplitude of the peak caused by a measurand can be detected with high precision. The advantages of phase-shifted interferometers for optical sensing include sensitivity enhancement, easy implementation, simple interrogation, and compactness, among others. The concept is demonstrated by placing two supermode interferometers in series that were built with multicore fiber to sense vibrations with low frequencies and low amplitudes. The sensing architecture proposed here can also be implemented with other types of optical fiber interferometers, and the advantages mentioned above can be achieved.

We will report on the development of optical sensors based on post-processing of conventional and photonic crystal fibres. In particular possible schemes of sensor heads for harsh environment and biological analysis will be presented.