The study of military style exhaust nozzles to further understand their acoustic characteristics has been the recent focus of the Pennsylvania State University high-speed jet aeroacoustics facility. Advanced measurement techniques are required to study the turbulence characteristics of the flow field. Development of a laser Doppler velocimetry system would allow for these measurements to be made non-intrusively.Development of the laser Doppler velocimetry system required research and testing of each component as it was placed into the system. Development was split into two portions: fundamental or basic concepts and components, and advanced components. During these stages, many components, such as the transmitting and receiving probes, were fabricated, procedures were developed, and calibration of the transmitting probe was completed.Once the development stages were complete, the laser Doppler velocimetry system was used to measure subsonic flows of a cold air exhaust jet. Velocity measurements proved to be accurate to within 2% of calculated jet Mach numbers with discrepancies of up to 6% at Mach numbers approaching 1 at x/D of 2. Comparison of axial turbulence intensity data to previous studies yielded less favorable result possibly due to use of the exhaust fan, but this hypothesis cannot be proven without more experiments.Parametric studies were also on the ratio of the injection pressure ratio to the nozzle pressure ratio and the exhaust fan power determine their effects of seeding on measurement values. It was determined that ratio of the injection pressure ratio to the nozzle pressure ratio had negligible effect on the measurements except at a value of 1 where the axial turbulence intensity was up to 6% different than the other measurements. However, the ratio was found to have an inverse relationship to the number of validated burst particles per unit time. The power of the exhaust fan created differences in the measurement of up to 3% at x/D greater than 6, with higher values of Mach number and lower values of axial turbulence intensity at the exhaust fan power of 15%. However, it is difficult to draw conclusions with only two sets of data.