Unusual Influence of Relaxation Oscillations on the Optical Spectrum of 890-nm Vertical-Cavity Surface-Emitting Lasers

Atypical effects have been discovered in the optical spectra of a series of single-mode vertical-cavity surface-emitting lasers near the threshold lasing current, including a large number of relaxation sidebands of comparable amplitude, a change in the nature of the spectrum asymmetry with increasing pump current, and distortion of the Lorentzian profile and its transformation into a double-peaked structure in the initial stage of evolution for one of the laser samples. A qualitative explanation is provided for some of these effects. The possibility of developing a theory for an appropriate description of the spectra in the near-threshold current region is discussed.