Concave VCSEL Aperture for Lower Noise Optical Communication

The patent applies asymmetry by changing the aperture shape from a conventional circular symmetric form to an asymmetric shape with at most one axis of symmetry. This asymmetric aperture configuration modifies the optical mode distribution, separating higher-order modes and reducing their contribution to intermodal beat notes, thereby decreasing relative intensity noise and enabling higher data transmission speeds without requiring complex additional components

The patent applies parameter changes by modifying the aperture shape parameters from a conventional circular geometry to an asymmetric geometry with specific constraints (at most one axis of symmetry). This parameter change fundamentally alters the optical mode confinement and separation, reducing spectral bandwidth and relative intensity noise. The patent provides specific design guidelines for the asymmetric shape to balance performance improvement with manufacturability

The patent applies the blessing in disguise principle by converting the harmful effect of higher-order modes (which cause intermodal beat notes and relative intensity noise) into a beneficial effect. The asymmetric aperture configuration separates higher-order modes spatially and reduces their overlap, transforming them from a source of noise into modes that can be managed separately. This allows the laser to maintain higher output power while the intermodal beat notes are pushed outside the electrical bandwidth, eliminating their harmful noise effect