Optical signal processing for high-speed, reconfigurable fiber optic networks

Unrestricted The past decade has witnessed tremendous growth in telecommunication network traffic. The ever-increasing demand for bandwidth has been tackled primarily through wavelength-division-multiplexing technology. However, with the emergence of multimedia applications, the high-capacity transport capability offered by optical-fiber systems has started to move away from the network core towards the end users. This trend has led to diverse networks with critical interoperability needs. As single channel data rates increase and wavelength channel spacing continues to reduce in order to enable cost-effective, high spectral efficiency links, the work load on the conventional electronic signal processing elements in the network routers is building up. Signal processing in the optical domain can potentially alleviate this bottleneck if the properties unique to the optical domain are leveraged efficiently to assist conventional electronic processing methodologies. Ultra-high speed capability along with the potential for format-transparent and multi-channel operation make optical signal processing an attractive technology poised to make a big impact on future optical networks.; At this juncture, exploration of optical signal processing techniques for applications in fiber optic network subsystems is a laudable goal. This dissertation investigates novel optical signal processing techniques through experimental demonstrations, identifies drawbacks and limitations of optical processing elements and proposes techniques to minimize the system-level penalties induced by them.; The results described include the design and development of all-optical logic modules including an XNOR gate and a serial half adder. A digital module to implement all-optical hard-limiting in optical code-division-multiple-access networks to alleviate the 'near-far' effect is also presented. Non-idealities in semiconductor optical amplifier-based differential-mode wavelength converters are analyzed and experimental techniques to compensate for data pattern dependence and deleterious sub-pulses are demonstrated. Additionally, a 160 Gb/s optical time division multiplexing system has been constructed and nonlinear signal processing techniques have been proposed to extend its applicability to the generation of phasecorrelated modulation formats that are starting to emerge as important candidates for future high spectral efficiency, robust transmission systems.