Fiber Optic Tutorials

This is a continuation from the previous tutorial - laser oscillation dynamics and oscillation threshold.   1. Introduction The degree to which fiber impairments are compensated determines the transmission capacity of fiber-optic transmission systems. Dispersion-compensating fiber (DCF) is commonly used to compensate chromatic dispersion.Wavelength-division multiplexing (WDM) systems suffer from both intra- and interchannel nonlinearities such as cross-phase modulation (XPM) and four-wave mixing (FWM). These effects can be suppressed using dispersion management. Compensation of nonlinear impairments in fiber has become the next logical step in increasing the capacity of WDM systems. A few optical nonlinearity compensation schemes have been demonstrated such...

This is a continuation from the previous tutorial - hermetic optical fibers - carbon-coated fibers.   In this tutorial we discuss a number of additional topics related to the elementary properties of laser oscillation. We consider first the oscillation build-up time with which coherent oscillation develops from noise in a laser cavity. From this we develop a set of simple coupled rate equations which link cavity photons to laser atoms, and laser atoms to cavity photons. Using these equations we explore further the laser oscillation buildup and the remarkable threshold properties characteristic of the laser oscillator. We then examine briefly some...

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...