Degradation-robust 850-nm vertical-cavity surface-emitting lasers for 25Gb/s optical data transmission

Highly efficient fast vertical-cavity surface-emitting lasers (VCSELs) for the 850-nm spectral range, promising for the development of optical interconnections with a data transmission rate of 25 Gbit/s per channel, are fabricated and studied. Lasers with a selectively oxidized current aperture 6 $\mu$m in diameter demonstrate multimode lasing with a quantum efficiency of 35–45% and a threshold current of 0.5–0.7 mA in the temperature range 20–85$^\circ$C. According to the results of small-signal frequency analysis, the maximum modulation frequency of the lasers exceeds 17 GHz, with the rate of its increase with current exceeding 9 GHz/mA$^{1/2}$, which provides VCSEL operation at a rate of 25 Gbit/s in the entire working temperature range. Endurance tests for 3000 h did not reveal any sudden degradation of the lasers. The optical power at working point and the threshold current changed relative to that at the beginning of the tests by no more than 5 and 10%, respectively.