All-optical clock recovery in a Q-switching self-pulsating DFB laser.

摘要

The research presented in this thesis provides a thorough analysis of 10 Gb/s all-optical clock recovery in a Q-switching self-pulsating distributed feedback (DFB) laser. The analysis consists of a detailed comparison between a numerical model of the self-pulsating laser and an experimental Q-switching laser. This research examines the self-pulsating regime of operation, clock recovery in a line rate system, clock recovery in a burst system, as well as clock recovery within a regenerator to mitigate the effects of the various impairments accumulated on the data signal.; Tunable self-pulsation from 8 GHz to 12 GHz is demonstrated by varying the drive currents to the laser. The laser exhibits excellent line rate and burst mode clock recovery characteristics. This research is the first to fully characterize the operating conditions of the self-pulsating laser. Clock recovery is achieved for a wide range of return-to-zero (RZ) input signal conditions, such as duty cycle, peak power, extinction ratio, carrier wavelength, and state of polarization. The quality of the recovered clock when presented with distorted inputs signals is also determined. Particularly, clock recovery is achieved for an input signal with a very poor optical signal-to-noise ratio (OSNR) of 8 dB, residual dispersion (RD) of +/-375 ps/nm, and polarization mode dispersion (PMD) of 30 ps. Another particularly attractive feature of this clock recovery technique is the fast locking time of less than 20 bits. This fast locking time makes the self-pulsating laser an excellent candidate for burst networks. It is demonstrated that after the short locking sequence, the recovered clock from a burst of data has very similar performance characteristics when compared to the line rate recovered clock.; A second component of this research consists of demonstrating the importance of clock recovery in a 3R regeneration application. For the first time, all-optical clock recovery is used in conjunction with higher-order four-wave mixing (FWM) to perform all-optical 3R regeneration. Significant improvements in timing jitter (5.3 ps to 2.0 ps) and receiver sensitivity of (-27 dBm to -35.5 dBm) between the OSNR distorted signals and the regenerated signals are presented. A polarization insensitive 3R regenerator is also demonstrated for signals distorted with up to 70 ps of first-order PMD, resulting in an improvement in receiver sensitivity of up to 12.3 dB.