Fiber Optic Tutorials

This is a continuation from the previous tutorial - what are hollow-core fibers?   Extraordinarily short optical pulses can be generated in mode-locked lasers, and these pulses can then be amplified to very large energies in subsequent laser amplifiers. Such pulses can be used for laser ranging (laser radar, or lidar); for pulse-modulated optical communications, both in free space and especially along optical fibers; and as measurement probes for studying a very wide variety of ultrafast physical, chemical, and biological processes, in what has come to be known as picosecond spectroscopy. Pulse propagation both in passive optical propagation systems and...

This is a continuation from the previous tutorial - introduction to miniature and micro-optics.   1. Introduction The history of the development of optical fibers has been largely determined by various constraints stemming from the materials used for the fiber core. For example, in the case of long-haul telecom applications, it is essential to have very low losses at the wavelength of a reliable and commercially available laser. Because silica has very low losses over wavelengths ranging from the visible to the near infrared (IR), which coincide with the operating wavelengths of a number of readily available lasers, it became...

This is a continuation from the previous tutorial - spectrally efficient multiplexing - Nyquist-WDM.   1. Introduction Optical components come in many sizes and shapes. A class of optical components that has become very useful in many applications is called micro-optics. We define micro-optics very broadly as optical components ranging in size from several millimeters to several hundred microns. In many cases, micro-optic components are designed to be manufactured in volume, thereby reducing cost to the customer. The following paragraphs describe micro-optic components that are potentially useful for large-volume applications. The discussion includes several uses of micro-optics, design considerations for...

This is a continuation from the previous tutorial - laser amplification explained in detail.   This tutorial discusses the basics of the Nyquist signaling theory and various aspects regarding its application in coherent optical communication systems to improve the transport spectral efficiency (SE). An alternative, and dual, approach to achieve a high SE is based on the use of orthogonal frequency-division multiplexing (OFDM), which is described in the following tutorial.   1. Introduction After the advent of digital coherent technology, there has been a significant interest in using advanced multilevel modulation formats, in combination with advanced multiplexing techniques and efficient digital...

This is a continuation from the previous tutorial - introduction to photosensitive fibers.   In this tutorial we examine the other side of the laser problem—that is, what laser atoms do to applied signals, rather than what applied signals do to atoms. This tutorial is concerned primarily with continuous-wave or "cw" laser amplification: how inverted atomic transitions amplify optical signals; what determines the magnitude and bandwidth of this gain; how it saturates; and what phase shifts are associated with it. In later tutorials we will consider pulse propagation and pulsed laser amplification and we will add the laser mirrors to these amplifying atoms, and be...