A novel parallel and implicitly-exhaustive search algorithm for finding, in systematic form, rate R = 1 2 optimalspan Convolutional Self-Doubly Orthogonal (CDO) codes and Simplified Convolutional Self-Doubly Orthogonal (S-CDO) codes is presented. In order to obtain high-performance low-latency codecs with these codes, it is important to minimize their constraint length (or "span") for a given J number of generator connections. The proposed exhaustive algorithm uses algorithmic enhancements over the best previously published searching techniques, yielding new and improved codes: we were able to obtain new optimal-span CDO/S-CDO codes (having order J ∈ {9} and J ∈ {10, 11} respectively), as well as new codes having the shortest spans published to date for higher values of J (J ∈ {10, 12, ..., 17} and J ∈ {12, ..., 20} for CDO and S-CDO codes respectively). The new codes and their error performance are provided. An analysis of the evolution of the CDO/S-CDO code error performance as J increases is presented, and the shortest CDO/S-CDO code span values for each given J are compared.