Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 7: Quantum dots and wires: Optical properties I

HL 7.3: Vortrag

Montag, 27. März 2006, 10:45–11:00, POT 151

Noise properties of ultrabroadband Quantum Dot Superluminescent Light Emitting Diodes — •Martin Blazek, Joachim Kaiser, Tobias Gensty, and Wolfgang Elsäßer — Institut für Angewandte Physik, Technische Universität Darmstadt, Schloßgartenstraße 7, D-64289 Darmstadt

Incoherent light applications, for example, Optical Coherence Tomography (OCT), require high power, low noise, and broad bandwidth light sources. We experimentally investigate the intensity noise properties of ultrabroadband Superluminescent Light Emitting Diodes (SLEDs), which are based on Quantum Dot structures. The spectral emission bandwidth of more than 50 nm (FWHM) is associated with a short coherence length guaranteeing a high axial resolution in OCT operation. The examined SLEDs emit more than 30 mW centered around 1300 nm. In a direct noise detection setup, we use a large area InGaAs photodiode to detect the emitted light. The amplified photocurrent noise is measured with an Electrical Spectrum Analyzer and normalized to the shot noise level. Spatially, spectrally and polarization resolved measurements are performed to reveal relations between the noise behavior and the SLEDs specific spatial and spectral emission properties. The results will be discussed with respect to device characteristics and OCT applications.