Streak camera analysis of dynamic characteristics of current modulated diode laser arrays
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- Diodes; Semiconductor; Semiconductor lasers; Mode-locked lasers; Diodes, Semiconductor
thesis / dissertation description
Phase-locked arrays of diode lasers emit high optical power in a spatially coherent beam. Emission can be controlled through modulation of the drive current enabling these phased array devices to produce short, high power optical pulses. The combination of these characteristics makes them directly applicable to high data rate communication systems. The temporal stability of phased arrays under pulsed operation is especially important when considering applications such as optical communication systems; however, the dynamic characteristics of these arrays are not yet well understood. A streak camera video frame-grab system was developed to analyze the dynamic characteristics of the radiation emitted by current modulated diode laser arrays. The use of a streak camera is a significant departure from the more traditional observation of the emission with a photodiode since the streak camera permits measurements to be made on a single pulse with a time resolution of a few picoseconds. In addition, the streak camera provides a three-dimensional record of intensity versus space and time which makes possible the simultaneous observation of the evolution of the intensity profile for each of the individual emitters in the array or particular spatial features of the far field. Software needed to analyze and display the intensity data has been developed. Using this software discrete fourier transforms and cross correlations of the near-field intensity of the emitters in the array, noise spectra, and halftone and graphical representations of the near- and far-field patterns' evolution may be obtained.