Fiber Optic Tutorials

This is a continuation from the previous tutorial - optical fiber coatings.   Our first major objective in this tutorial is to understand how optical signals act on atoms (or ions, or molecules) to excite resonance responses and to cause transitions between the atomic energy levels. In later tutorial we will examine how the excited atoms or molecules react back on the optical signals to produce gain and phase shift. Eventually we will combine these two parts of the problem into a complete, self-consistent description of laser action. For the minute, however, all we want to consider is what optical fields do to atoms....

This is a continuation from the previous tutorial - relay trains and periscopes.   Introduction It could be said that the modern era of fiber optics began in 1966, with the publication of the paper ‘‘Dielectric-Fibre Surface Waveguides for Optical Frequencies‘‘ by Dr. C. K. Kao and G. A. Hockham of Standard Telecommunications Laboratories Ltd. (STL). This paper discussed the theory and potential use of optical fiber for communications. Dr. Kao believed that fiber loss could be reduced below 20 dB/km by eliminating metal impurities in the glass. Such attenuation would allow 1% of the light entering 1 km of...

This is a continuation from the previous tutorial - galilean and inverse galilean afocal lenses.   There are many applications where it is necessary to perform remote viewing because the object to be viewed is in an environment hostile to the viewer, or because the object is inaccessible to the viewer without unacceptable damage to its environment. Military applications fall into the former category, and medical applications fall into the latter. For these applications, instrumentation is needed to collect light from the object, transport the light to a location more favorable for viewing, and dispense the light to the viewing...

This is a continuation from the previous tutorial - keplerian afocal lenses.   The combination of a positive objective and a negative eyepiece forms a galilean telescope. If the objective is negative and the eyepiece positive, it is referred to as an inverse galilean telescope. The galilean telescope has the advantage that it forms an erect image. It is the oldest form of visual telescope, but it has been largely replaced by terrestrial telescopes for magnified viewing of distant objects, because of field of view limitations. In terms of number of viewing devices manufactured, there are far more inverse galilean...

This is a continuation from the previous tutorial - a few practical laser examples.   A simple afocal lens can be made up of two focusing lenses, an objective and an eyepiece, set up so that the rear focal point of the objective coincides with the front focal point of the eyepiece. There are two general classes of simple afocal lenses, one in which both focusing lenses are positive, and the other in which one of the two is negative. Afocal lenses containing two positive lenses were first described by Johannes Kepler in Dioptrice, in 1611, and are called keplerian....