Static and dynamic properties of vertical-cavity surface-emitting semiconductor lasers with incorporated two-dimensional photonic crystals

Abstract

In oxide-confined Vertical-Cavity Surface-Emitting Lasers (VCSELs) the single-mode radiation is desirable for many applications. The single longitudinal mode is typical in VCSELs, however transverse optical modes can be controlled either with a small oxide aperture size [2] or small micropillar-like etched top distributed Bragg reflectors (DBRs) [3]. However, the power radiated from single-mode VCSELs is low and it results in low transmission distance in optical telecommunication networks. The power can be increased due to the fabrication of wider oxide aperture and wider top DBR, but than a VCSEL becomes multimode. Since the last decade photonic crystals had been introduced to control transverse optical modes of VCSELs [4-8]. The PC is created by periodic modulation of the refractive index in one, two or three space directions. In the VCSELs, the PC is positioned in top DBR and fabricated due to etching air-filled holes in the DBR. It was demonstrated that the PC reduces the transverse optical mode number, spectral linewidth [4-8] and increases the modulation bandwidth of VCSELs [9]. In this paper we present results of the investigated VCSELs with incorporated photonic crystals fabricated using the focused ion beam (FIB) machine. Power versus current, spectral and modulation characteristics of VCSELs with PC are investigated and compared to similar VCSELs with etched mesa.