A method for introducing phase steps in an interferogram based on translating a ruling at the input plane of a double aperture common-path interferometer is presented. The setup is built on a 4f optical system consisting of two apertures at the input plane and a Ronchi ruling in the Fourier plane, where at each aperture a Ronchi ruling is also placed. By filtering at the Fourier plane a single diffraction order of the spectrum from the rulings in the object plane, we demonstrate that a phase step is generated when one of the rulings in the input plane is translated. The principal advantage of this proposal lies in improving the resolution in the phase step. We develop a theoretical model and show experimental results.

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In this manuscript a method is proposed to estimate the wavelength of a laser diode source, under the scheme of a two-source Twyman–Green interferometric setup. This proposal is based on the count and ratio of the interfering fringes generated by two laser diode sources with a standard and unknown wavelength when they are independently switched on–off. The viability of the proposed experimental setup allows it to be easily replicated and used for research or teaching purposes, where special topics in optics for undergraduate or graduate students are required.

Optical fibers are widely used in different areas, such as industry, research, and education, just to mention a few. Due to this fact, their applications are commonly included in undergraduate engineering programs or in related fields of education. In this article, a new low‐cost educational resource for a better understanding and a practical application of optical fibers is proposed. The main purpose of this resource is to send 4‐bit images in grayscale through optical fibers with a laser diode and receive it with a photoresistor, with a total estimated setup‐cost of fifteen dollars. The setup includes a visual user‐interface programmed with the software LabVIEW, which lets to select and prepare an image for a proper sending. The same program is in charge of applying different intensities for each type of bit through a generic laser diode and of receiving the information back, all done with the aid of an Arduino Uno board, which serves as the electric interface.

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