The design and analysis of optical signal processing elements for high-speed optical recievers

The history of communications has been one of increasing demands for higher and higher bit-rate communications over longer distances. The desired bandwidth is now greater than what can be achieved through traditional all electrical communication systems. Therefore, more and more communication systems are employing optical fiber communications to achieve the required data rate. While optical fibers do have the required bandwidth, the data must still be converted into the electrical domain prior to final delivery from the network. This optical to electrical conversion process currently has a significantly smaller bandwidth than the optical fibers and thus places an upper limit on the achievable data rate. This is known as the electrical bottleneck. In this thesis we propose to employ optical signal processing devices to pre-process the data prior to optical to electrical conversion. This processing will result in less post-detection electronics and hence a larger bandwidth.;The principle optical signal processing device studied in this thesis is the optical tripped delay line filter. This structure, which can be manufactured from basic optical waveguide elements and couplers, is capable of realizing a wide variety of transfer functions. This makes an attractive device for implementing many important optical receiver functions. In addition, the transfer function of a tapped delay line filter is equivalent to normal digital tapped delay lines. This allows one to apply the bulk of the digital signal processing technique to it and thus simplify the process of synthesizing the required filter.;One of the principal challenges in applying optical signal processing techniques to the optical to electrical conversion process is obtaining an accurate model for the detection process. The use of traditional detection models to analyze pre-processed arbitrary optical signals is insufficient. In particular, developing a model which accurately predicts the performance of optical signals corrupted by noise from optical amplifiers is particularly challenging. In this thesis we develop an accurate statistical model which is capable of predicting the performance of the optical detector when excited by arbitrary random signals. In addition, this model allows one to perform an optimization of the receiver elements to achieve the transfer function of the optimal noise filter.;With the use of the tapped delay line filter, and the improved detection model, one can then propose and analyze a scheme to increase the bandwidth of the optical to electrical interface. In this work we study a method to use optical correlators to realize matched filtering and all optical clock recovery. This allows one to employ a multi-symbol signaling scheme which can exploit parallelism in the proposed optical detectors to increase the transmission rate. In addition, the all optical clock recovery removes the requirement for a phase-locked loop which greatly reduces the cost of the receiver while increasing its bandwidth.