The dynamic range of optical fiber refractive index sensors is mainly determined by the refractive index (RI) of the sensor surface in contact with the sample under test. In case of the refractive index sensor based on the hybrid fiber Fabry–Perot interferometer (HFFPI), the largest measurable refractive index value is equal to that of the fiber core. In this work, we demonstrate that it is possible to extend the refractive index dynamic range of a HFFPI by simply adjusting the optical path length (OPL) of the air and solid cavity to be equal or differ by just a small amount. Two isometric versions of the HFFPI (i-HFFPI) with a total length of 100 and 172 μm, where the OPL of the air and solid cavity are very similar, were fabricated and tested. The interferometers were immersed in different samples with a refractive index ranging from 1.000 to 1.733. The response of the interferometers was analyzed in the Fourier domain, and it was possible to establish a one-to-one relationship between the refractive index of the liquid sample and the amplitude of one of the peaks in the Fourier spectra. The amplitude of this peak experienced a linear increment when the RI of the surrounding medium was increased. Tracking the amplitude changes of a Fourier spectrum peak is straightforward which simplifies the online monitoring of the sensor. These features make this compact refractive index fiber sensor very appealing for biosensing applications.

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This work shows an alternative approach for teaching basic concepts of optics and acoustics, addressed to people with visual disabilities. We describe in detail how concepts as wave, period, frequency, wavelength, maximum, minimum, amplitude, reflection, transmission, and absorption are explained through adapted experiments. The workshop has been implemented 3 times so far, benefiting 20 people with visual disabilities and 60 people with multiple disabilities. On the other hand, this work also shows some dynamics that can be done with people without disabilities to raise awareness and identify the needs that we have as a society to be inclusive in a sector as important as education. In this sense, this workshop has been attended by 90 people without disabilities of which some of them are currently volunteers in the execution of the workshop. Finally, the work also talks about other ideas that have arisen during the development of this project and how they plan to get going in the near future.

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Red blood cell (RBC) anomalies are significant symptoms for identification of health disorders and several blood diseases, which involve the modification of the parameters and biophysical characteristics of such cells. An optical system was implemented using a Mirau interferential objective to evaluate the micro-topography of Red Blood Cells in Papanicolaou test (PAP). The phase-shifting algorithm called 8-Bell6 was applied to evaluate the phase map. The phase ambiguity is removed by using three light-emitting diodes (LEDs) emitting at three different wavelengths: 459.7, 512.8 and 637 nm. The micro-topography is evaluated for one of the RBC observed in the sample. Profiles of two perpendicular diameters to each other are showed. The relative error for measurements made with this optical system is 2.9%.