This thesis details the development of an optical diagnostic capable of making simultaneous, instantaneous measurements of the soot volume fraction, soot primary particle diameter, and soot mean aggregate radius of gyration in large, turbulent, non-premixed flames. A combination of auto compensating laser induced incandescence and elastic light scattering was used to make the measurements. The produced optical measurement system was validated by quantifying soot within a reference co-annular laminar diffusion flame. Results agreed with the published data at the same flame conditions within precisely calculated measurements uncertainties obtained with Monte Carlo analysis. This analysis revealed that with larger optical measurement volumes the overall uncertainties are dominated by uncertainty in the optical and fractal properties of soot which are common to all optical diagnostics. The results demonstrate that the developed soot measurement system is ready to be used to make measurements on large turbulent flames.