Department of Electronic & Electrical Engineering, Unit Catalogue 2006/07

EE30122 Optical communications

Credits: 6

Level: Honours

Semester: 1

Assessment: EX100

Requisites:

Aims: To describe the fundamentals of optical (fibre) communications systems and key components.
Learning Outcomes:
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.
Skills:
Intellectual skills: basic maths, electromagnetic waves and semiconductor devices.
Content:
Overview of optical communications systems and basic components. Optical Fibres: types of fibre, simple ray model, Snell's Law, numerical aperture, number of modes, intermodal dispersion and fibre bandwidth, chromatic dispersion, waveguide dispersion and their effect on fibre bandwidth. Attenuation and dispersion characteristics of fibre - impact of choice of optical source wavelength and detector. Fibre jointing and interconnections. Optical sources: LEDs and lasers, review of the development of laser structures. Gain curve. Structures for single wavelength operation. Modulation response of lasers (simple analysis using rate equations). Description of basic principles of operation of DFB 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, timing budget, effect of chirp and polarisation on system bandwidth, requirements of (i) high data rate links, (ii) wavelength division multiplexing, (iii) metropolitan area networks and (iv) local area networks and optical Ethernet.

University | Catalogues for 2006/07