GaAs based quantum dot superluminescent diodes for optical coherence tomography of skin tissue

The development of high power broad bandwidth quantum dot super-luminescent diodes (SLEDs) is described. The requirements for time domain optical coherence tomography is described and the suitability of GaAs based quantum dots (QDs) highlighted. The effect of reducing QD deposition temperature is shown to be beneficial for broadband applications, and the fabrication of such material into single-pass multi-contact SLEDs is outlined. The operating characteristics of these devices are discussed in terms of power, emission bandwidth, spectral shape, axial imaging resolution, and sensitivity to optical feedback. Finally the effect of increased bandwidth and power on the imaging of skin tissue is practically demonstrated.