Transverse detuned loading for modulation bandwidth enhancement in VCSELs

Giacomo Graziano; Richard Schatz; Antoine Pissis; Wilfried Maineult; Aurelio Rossinelli; Philipp Täschler; Simon Hönl; Vincenzo Pasanisi; Tobias Süss; Dario Schiavon; Donato Bonfrate; Martin Spieser; Stefano Tirelli; Evgeny Zibik

arXiv · 2610.35578

Transverse detuned loading for modulation bandwidth enhancement in VCSELs

Giacomo Graziano·Richard Schatz·Antoine Pissis·Wilfried Maineult·Aurelio Rossinelli·Philipp Täschler·Simon Hönl·Vincenzo Pasanisi·Tobias Süss·Dario Schiavon·Donato Bonfrate·Martin Spieser·Stefano Tirelli·Evgeny Zibik

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Abstract

Directly modulated vertical-cavity surface-emitting lasers (VCSELs) are central to short-reach optical interconnects, where modulation bandwidth and power efficiency are critical factors for increasing data transfer capacity. Conventional oxide VCSELs still require power-hungry signal processing to achieve high-speed data transmission above 100 Gb/s. Here we report an experimental implementation of detuned loading in a VCSEL to enhance the modulation bandwidth. The detuned loading is achieved by carrier-induced index variations that reshape an engineered transverse mode so its overlap with spatially selective optical losses decreases with increased carrier density. This produces a negative differential loss reminiscent of that in detuned-loaded DBR lasers lasing on the long-wavelength reflectivity flank. The resulting 850 nm single-mode VCSEL exhibits an enhanced carrier-photon relaxation frequency of 44 GHz, yielding a 3dB electrical modulation bandwidth exceeding 50 GHz. The enhancement persists from 25 °C to 75 °C showing the robustness of the mechanism introduced. The same device supports 106.25 Gb/s NRZ transmission without digital signal processing, transmitter pre-emphasis or receiver equalization. These results establish transverse detuned loading as a robust alternative approach for extending the modulation bandwidth of vertical-cavity surface-emitting lasers.

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Giacomo Graziano, Richard Schatz, Antoine Pissis, Wilfried Maineult, Aurelio Rossinelli, Philipp Täschler, Simon Hönl, Vincenzo Pasanisi, Tobias Süss, Dario Schiavon, Donato Bonfrate, Martin Spieser, Stefano Tirelli, Evgeny Zibik. 2026-10-26. Transverse detuned loading for modulation bandwidth enhancement in VCSELs. https://arxiv.org/abs/2610.35578

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