Intrinsic Modulation Response and Electrical Parasitics in Oxide‐confined Vertical‐Cavity Surface‐Emitting Lasers Based on Single or Multiple Apertures

ABSTRACT Small aperture (∼2 µm) oxide‐confined single‐mode (SM) Vertical‐Cavity Surface‐Emitting Lasers (VCSELs) are capable of intrinsic optical modulation bandwidth above 42 GHz at low currents (∼2 mA). The measured optical bandwidth is limited to ∼36‐38 GHz by the VCSEL resistance and capacitance (RC parasitics). To match requirements for industrial VCSELs, we applied a single mesa multi‐aperture (MA) single‐mode (SM) VCSEL design. The design is based on 4 diamond‐shaped apertures at ∼10 µm pitch and an effective diameter of a single aperture of ∼1.7‐2 µm. Higher capacitance of the large VCSEL mesa is compensated by a reduced resistance (50Ω) of the device, allowing optical bandwidth f ‐3dBo ∼32 GHz. The intrinsic optical bandwidth f ‐3dBo of ∼45 GHz is extracted. MA SM VCSEL allows narrow spectral width and error‐free 50‐Gbaud data transmission over 200 m OM5 multimode fibre (MMF).