Department of Electronic & Electrical Engineering, Unit Catalogue 2007/08
EE40130 Optical devices and communications systems
| Credits: 6 |
| Semester: 1|
|Assessment: EX 100%|
Aims: To describe the fundamentals of optical (fibre) communications systems and key components.
After completing the unit the student should have a clear understanding of:
* the characteristics of the optical fibre;
* the basic principles of operation of optical communications systems and components;
* the design rules for (i) a high capacity trunk optical network, (ii) a metropolitan area fibre network and (iii) an optical local area network.
Intellectual skills: basic maths, electromagnetic waves and semiconductor devices.
Overview of optical communications systems and basic components.
Semiconductor lasers: principles of operation; Fabry-Perot resonator. Qualitative review of optoelectronic sources: LEDs, Superluminescent LEDs, designs for monochromatic sources (DFB laser), Gain curve. Structures for single wavelength operation. Modulation response of lasers. Coupling of input signal to optical fibre.
Optical Transmitters: requirements for stable pulsed laser operation, relaxation oscillations, chirp, use of optical modulators.
Optical Receivers: principles of photodiode operation, requirements for high speed photodetection, optical design of PIN photodiodes, signal-to-noise performance of photo-receivers, simple relationship between bit error rate and receiver signal-to-noise performance.
Performance of Optical Fibre Links: power budget, fibre dispersion and timing budget, effect of chirp and polarisation on system bandwidth, requirements of (i) high data rate links, (ii) wavelength division multiplexing, (iii) optical networks.