| This thesis describes two methods of bit error rate (BER) estimation based on statistical techniques. The first method examines the correlation between the BER and electrical characteristics of an optical receiver circuit. Low correlation is found between the receiver performance and the electrical characteristics. This may be caused by a high variability in the quality of the optical portion of the receiver as compared to the electrical portion. In the second method of BER estimation, a preselected analytic function was fit to samples of a signal and this function was used to calculate the probability of error of this signal. The analytic function modeled noise contributions from thermal and modal noise sources. Modal noise, caused by the interference of fiber modes at a surface, is modeled by a gamma distribution when a large number of modes are excited in the fiber. However, if a small number of modes are excited, the gamma distribution does not describe the observed noise distribution. A numerical model is presented which describes the noise distribution in this restricted mode-launch case. This represents the first time noise measurements of restricted mode-launch fiber optic links have been presented. |
