SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 43: Semiconductor lasers II

HL 43.4: Talk

Thursday, March 30, 2023, 16:00–16:15, JAN 0027

Monolithic 850 nm VCSEL Array for QKD via the decoy state protocol — •Michael Zimmer, Moritz Birkhold, Michael Jetter, and Peter Michler — Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart.

In recent years, the need for secure data communication has increased. Here, the usage of quantum key distribution (QKD) offers fundamental advantages over classical key distribution. However, despite its high level of security, QKD comes a long with numerous challenges regarding the application of single photons. In this view, the decoy state protocol offers the possibility to implement QKD using classical light sources such as semiconductor lasers. Here, we present an approach for the realization of a monolithic 850 nm eight VCSEL array capable for QKD via the BB84 and decoy state protocol. Growth of the VCSEL structure takes place by metal-organic vapor-phase epitaxy (MOVPE) on a GaAs substrate. In order to obtain defined light polarization states, each VCSEL features an integrated polarization grating in its light emission window. To allow for operation in the GHz-regime and hence a high key rate generation, the VCSEL are arranged in a co-planar contact design. Electro-optical device characteristics regarding light polarization and high frequency operation are presented.