A. K. Jansen van Doorn

Elasto-optic anisotropy and polarization orientation of vertical-cavity surface-emitting semiconductor lasers

We report a new technique to apply strain to a vertical‐cavity surface‐emitting semiconductor laser. This has allowed us to study the relation between strain and birefringence. We have found that the corresponding tensor is anisotropic, with a measured anisotropy 2p44/(p11−p12)=4.7±0.6. This anisotropy explains the natural preference of the polarization for the [110]/[110] axes.

Tailoring the birefringence in a vertical‐cavity semiconductor laser

We demonstrate a technique to modify the strain in a planar vertical‐cavity semiconductor laser. The technique consists of locally melting a hole in the wafer next to the device by means of a focused laser beam. This allows manipulating both the magnitude and the orientation of the native birefringence in a permanent way.

Polarization behavior of surface-emitting semiconductor lasers in an axial magnetic field☆

Abstract We show experimentally that the emission of a surface-emitting semiconductor laser becomes elliptically polarized in the presence of an axial magnetic field. This ellipticity is accompanied by a change of the mode spectrum. The overall results are consistent with a linear model describing the combined effect of birefringence and Faraday rotation. A weak onset of non-linear polarization behavior is observed; this is ascribed to the polarization dependence of the gain saturation.

Effect of spatial filtering on the spontaneous emission spectrum of a sub-threshold VCSEL

We have measured the optical spectrum of a vertical cavity surface-emitting laser (VCSEL) operating below threshold. The spectrum consists of a strongly asymmetric central peak with weak structures in the wings that denote the edges of the DBR stopband. We show that the striking asymmetry of the central resonant part is caused by rays emitted at an angle with respect to the surface normal. The asymmetry can be removed by spatial filtering in the far-field. Analysis of the so obtained Lorentzian spectrum yields the current-dependent cavity loss rate and resonance frequency and thus, provides a new tool to analyze VCSELs. >

Observation of wave front curvature inside a vertical‐cavity surface‐emitting laser

By performing interferometric measurements on the fundamental transverse mode of a planar VCSEL, we have determined the wave front curvature inside the VCSEL cavity. The results show that the (apparent) position of the beam waist is 0–8 μm below the surface of the top DBR, i.e., up to 25% of the Rayleigh range. From these results we estimate the amount of index and gain guiding in the VCSEL.

Mutual coherence of light emitted from the two mirrors of a subthreshold semiconductor laser

Abstract Experimentally is shown that the left and right output beam of a semiconductor laser are not perfectly correlated, particularly so below threshold. The difference can be attributed to the incoherent contribution of spontaneous emission during a single passage of the laser field through the active medium. The measurements thus provide information on the short-time evolution of the intracavity field. The results are compared with the long-time evolution, as characterized by the linewidth.