Fiber Optic Tutorials

This is a continuation from the previous tutorial - X-ray optics.   1. Introduction Hermetically coated optical fibers have a thin layer of an impervious material applied over the surface of the glass fiber. Hermetic coatings are used to improve the reliability of fibers by preventing strength degradation caused by moisture attack on the fiber surface, and by preventing the diffusion of hydrogen into the core of the fiber. The typical polymer coatings that are used on optical fibers are able to prevent liquid water from contacting the glass surface but are not able to stop the diffusion of H\(_2\)O...

This is a continuation of the previous tutorial - digital equalization in coherent optical transmission systems.   1. Introduction The following fundamental difficulties have served as a deterrent to the development of x-ray imaging systems: Adequate sources and detectors have not always been available; No suitable refractive material exists from which conventional x-ray lenses can be fabricated; Mirrors have traditionally exhibited useful reflectances only for grazing incident angles; Grazing incidence optical designs are cumbersome and difficult to fabricate and align; Scattering effects from imperfectly polished surfaces severely degrade image quality for these very short wavelengths; The absorption of x-rays by...

This is a continuation of the previous tutorial - fundamentals of laser oscillation.   1. Introduction Digital equalization within a coherent optical receiver has been critical to the wide-scale adoption of the digital coherent transceiver in core networks. Digital equalization has not only allowed optical chromatic dispersion to be removed from the line, but more critically it removed the limits imposed by the polarization-mode dispersion (PMD) to upgrading legacy systems. Given this tutorial is concerned with digital equalization, before going in to detail we segue to discuss what is meant by digital equalization in contrast to mitigation. Mitigation is defined by the...

This is a continuation from the previous tutorial - mid-IR and infrared fibers.   This tutorial brings us finally to the complete laser oscillator: atoms, plus pumping and population inversion, plus signals and amplification, plus mirrors to provide feedback and oscillation. In this tutorial we will develop formulas for some of the simpler aspects of laser operation, including the population inversion required to reach oscillation threshold; the pumping power density required to produce this inversion; the laser power output, and its dependence on output coupling and pumping power in simple cases; the difference between homogeneously and inhomogeneously broadened lasers; and the atomic-frequency pulling...

This is a continuation from the previous tutorial - optical fibers and fiber optic communications.   1. Introduction Infrared (IR) optical fibers are fibers that transmit radiation from 2 to approximately 20 μm. The first IR fibers were fabricated in the mid-1960s from a rather special class of IR transparent glasses called chalcogenide glasses. It was well known that mixing chalcogen elements, for example, arsenic and sulfur, can form a dark red glass that is transparent well beyond 2 μm. In 1965, this arsenic trisulfide (As2S3) glass was first drawn into crude optical fiber by Kapany et al., but the...