Experimental demonstration of techniques to improve system performance in fiber-optic communication systems using subcarrier-multiplexed and digital baseband signals.

摘要

The overall performance of light-wave communication systems and networks using subcarrier-multiplexed and digital baseband signals may be degraded for various reasons. For instance, chromatic dispersion of standard single mode fiber causes pulse distortion for digital transmission systems and microwave power fading in subcarrier-multiplexed fiber-optic links. These effects can result in unacceptable power penalties and even complete signal loss. Furthermore, fiber dispersion may de-synchronize bit-parallel data in wavelength division multiplexed (WDM) interconnections, where each parallel bit is located on a parallel wavelength and transmitted simultaneously. However, these bits must be synchronized upon reaching the receiver to ensure correct data recovery.; Polarization mode dispersion (PMD) is one of the next challenges in optical communication systems after the successful mitigation of chromatic dispersion effects. Transmission of ultra-fast digital baseband and subcarrier multiplexed signals over fiber will be severely affected by PMD, although its statistical impact has not yet been thoroughly investigated. Therefore, it is imperative to examine the fading characteristics of such signals using a realistic PMD source that closely emulates the statistical nature of PMD in single mode fiber.; Another important factor is to ensure efficiency in the switching process at each node to achieve high throughput in WDM optical networks. Consequently, output-port contention, in which data packets at the same wavelength on two input ports request to be routed to the same output port, must be rapidly resolved. To combat the mentioned performance degrading effects, all-optical techniques are highly desirable to enable high-speed on-the-fly processing, which would be essential for future high throughput and dynamically reconfigurable optical networks.; This dissertation will present the following experimental demonstrations to investigate and enhance the system performance of next-generation optical networks: (1) Bit synchronization for WDM interconnections using two subcarrier-multiplexed control pilot tones; (2) Output-port contention resolution using optical subcarrier-multiplexing; (3) Distance-independent power fading compensation using a tunable nonlinearly-chirped fiber Bragg grating; and (4) Statistics of PMD-induced fading penalties of subcarrier-multiplexed and digital baseband signals.