Abstract

Commercial devices for optical coherence tomography greatly benefit from the appealing features of broadband light emitting quantum dot superluminescent diodes (QDSLDs). Here, light generation occurs at the transition of spontaneous to stimulated emission, the regime of amplified spontaneous emission (ASE), where initially spontaneously emitted photons are amplified by stimulated emission processes during their propagation through the device, enabling strong light amplification. The delicate choice of waveguide geometry and gain medium, here the quantum dots (QDs), enables large spectral widths of some THz (see Fig. 1 (left)) as well as spatial coherence. Modern measurement methods based on detectors [1], which take advantage of the two photon absorption process (TPA), already theoretically predicted by B. R. Mollow in 1968 [2], provide a temporal resolution high enough to detect this radiation with coherence time in the order of fs and permit correlation studies of QDSLDs.

© 2017 IEEE