Detection and optical signal processing using phase based optical modulation formats

Increased data traffic demands, along with a continual push to minimize cost per bit, have recently motivated a paradigm shift away from traditional on-off keying (OOK) fiber transmission links towards systems utilizing more advanced modulation formats. In particular, phase based modulation formats, including differential phase shift keying (DPSK) and differential quadrature phase shift keying (DQPSK) have recently emerged as the most popular means for transmitting information over long-haul and ultra-long haul fiber transmission systems. DPSK is motivated by an increase in receiver sensitivity compared to traditional OOK. DQPSK is motivated by a doubling of the spectral efficiency, along with increased tolerance to dispersion and nonlinear distortions.;The main drawback of phase-based transmission systems is an increase in complexity, particularly at the receiver side where differential phase-to-intensity conversion is required prior to photodetection. This thesis presents a number of alternative receiver designs for DPSK and higher-order phase-based modulation formats. The presented receiver designs are potentially more compact, stable and cost-effective compared with more traditional detection techniques.;In addition to advanced modulation formats, it is expected that optical signal processing may play a role in the future development of more efficient optical transmission systems. The hope is that performing signal processing in the optical domain may reduce optical-to-electronic conversion inefficiencies, eliminate bottlenecks and take advantage of the ultrahigh bandwidth inherent in optics. A critical element to achieve efficient and reconfigurable signal processing is tunable optical delay lines. This thesis will also present a method for achieving extremely large continuously tunable optical delays using wavelength conversion and chromatic dispersion. The presented delay line is also utilized to enable signal processing functionalities such as time-slot interchange and optical data multiplexing. Additionally, a linear feedback shift register is presented with potential applications, including optical random data generation, clock division and packet generation.