Lasers are ubiquitous in current society creating a need for an understanding of the principles of lasers. Furthermore optical communications has connected the world with high speed information delivery. This advanced module will give a qualitative and to a lesser extent, quantitative understanding of the physics of lasers and relates some applications of lasers to these physical properties. It also includes an introduction to optical communications based on physical principles of light production, transmission and detection. The limitations on such systems are explored and methods to overcome these limitations are developed
Indicative syllabus covered in the module and / or in its discrete elements
Laser operations will be reviewed and the rate equations for three and four level systems, the rate equation solutions, threshold, inversion density, optical power output and efficiency introduced. Properties of laser light, coherence and linewidth, applications of coherence. Directionality and brightness, applications, non-linear effects, parametric oscillators. Practical systems, spectroscopy and pumping mechanisms, output wavelengths and powers. Q-switching and mode-locking.
Systems; Source drive circuits, limitations, modulation techniques. Receiver design and implementation, noise and bandwidth compromise, signal to noise ratios, error rates, pre and post amplification including optical preamplifiers. Attenuation and compensating amplification. Dispersion and dispersion compensation. Digital systems requirements, analogue systems requirements. Applications; Digital transmission systems for single channel short and long haul links. WDM, and optically amplified links, analogue CATV systems, unguided systems, space links.
Methods include lectures, discussion in class, problem-solving exercises within class; text books and programme notes provided on Webcourses and other online resources; self-directed learning.
|Module Content & Assessment