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HL: Fachverband Halbleiterphysik
HL 12: Semiconductor Lasers I
HL 12.7: Vortrag
Montag, 18. März 2024, 16:30–16:45, EW 561
Free space emission spectra and bandwidths of vertical cavity surface emitting lasers — •Pouria Emtenani1, Nasibeh Haghighi1, Martin Zorn3, Markus R Wagner1,2, and James A Lott1 — 1Technical University of Berlin — 2Paul-Drude-Institut Berlin — 3JENOPTIK Optical Systems GmbH, Berlin
We measure and analyze the free space (across air) emission spectra and small-signal modulation bandwidths of top-emitting 980 nm vertical cavity surface emitting lasers (VCSELs) and electrically parallel VCSEL arrays. We design and fabricate the VCSELs at the Technical University of Berlin [1] and test them using on-wafer high-frequency probing. The VCSEL emission is collected into a standard OM2 multiple-mode optical fiber patch cord with a length of 10 meters which in turn directs the optical signal into a triplet-lens fiber collimator. The light exits the fiber collimator as a free space beam. A second triplet-lens fiber collimator collects the light and directs it into a second OM2 fiber patch cord with a length of 3 meters which then directs the optical signal into an optical spectrum analyzer or onto a high bandwidth photodiode connected to a 2-port vector network analyzer. We achieve a free space bandwidth across 0.4 and 4.5 meters of air of 16 GHz for a 19-element array and 25 GHz for a single VCSEL, a crucial first step toward free space data transmission at 25 Gbps or faster for future, sixth generation optical wireless communication systems, Internet of Things connectivity, and next generation light fidelity systems. [1] N. Haghighi, Dissertation. [online] https://depositonce.tu-berlin.de/handle/11303/16321
Keywords: VCSEL; Vertical cavity surface emitting laser; Free space optical communication; Optical wireless communication; Light Fidelity (LiFi)