1. Angled Flip-Chip Integration of VCSELs on Silicon Photonic Integrated Circuits
- Author
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Mehdi Jahed, Alexander Caut, Jeroen Goyvaerts, Marc Rensing, Magnus Karlsson, Anders Larsson, Gunther Roelkens, Roel Baets, and Peter O'Brien
- Subjects
Optical waveguides ,Silicon-nitride photonic integrated circuit ,Vertical cavity surface emitting lasers ,Couplings ,Diffraction gratings ,Physics::Optics ,Optical feedback ,Diffraction ,Gratings ,Atomic and Molecular Physics, and Optics ,Coupling efficiency ,Flip-chip integration - Abstract
An investigation of angled flip-chip integration of a singlemode 850 nm vertical-cavity surface-emitting laser (VCSEL) on a silicon nitride photonic integrated circuit (PIC) is presented. Using numerical FDTD simulations, we consider the conditions under which the VCSEL can be integrated at an angle over a grating coupler with high coupling efficiency and low optical feedback. With both coupling efficiency and feedback decreasing with increasing angle, there is a trade-off. With co-directional coupling, first-order diffraction loss sets in at a critical angle, which further reduces the coupling efficiency. No such critical angle exists for contra-directional coupling. We also experimentally demonstrate angled flip-chip integration of GaAs-based 850 nm single transverse and polarization mode VCSELs over grating couplers on a silicon-nitride PIC. At the output grating coupler, light is either collected by an optical fiber or converted to a photocurrent using a flip-chip integrated GaAs-based photodetector. The latter forms an on-PIC optical link. We measured an insertion loss of 21.9, 17.6 and 20.1 dB with a singlemode fiber, multimode fiber and photodetector over the output grating coupler, respectively.
- Published
- 2022
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