Fig. 1. (Color online) (a) Cross-sectional schematic of the cryogenic VCSEL structure. (b) Packaged cryogenic VCSEL mounted in a cryostat.

Fig. 2. (Color online) Schematic of the temperature-dependent misalignment between the gain peak and the F−P dip.

Fig. 3. (Color online) (a) Measured L−I−V curves of the cryogenic VCSEL at RT (298 K). (b) Measured L−I−V curve of the cryogenic VCSEL at 3.6 K. (c) Lasing spectra of the cryogenic VCSEL at 5 mA within the temperature range from 298 to 3.6 K. (d) Lasing spectra of the cryogenic VCSEL under different currents at 3.6 K. (e) Wavelengths of the fundamental mode of the cryogenic VCSEL at 5 mA under different temperatures. (f) Wavelengths of the fundamental mode of the cryogenic VCSEL at 3.6 K under different currents.

Fig. 4. (Color online) (a) Small signal responses S₂₁ of the VCSEL at RT (298 K). The inset shows the VCSEL chip mounted on a carrier with GSG pads. (b) Small signal responses S₂₁ of the VCSEL at 292 K.