The invention relates to
vertical cavity lasers (VCL) incorporating a
reflectivity-modulated
grating mirror (1) for modulating the
laser output. A cavity is formed by a bottom mirror (4), an active region (3), and an outcoupling top
grating mirror (1) formed by a periodic
refractive index grating region in a layer structure comprising a p- and a n-doped
semiconductor layer with an electrooptic material layer (12) arranged there between. The grating region comprises a grating structure formed by periodic perforations to change the
refractive index periodically in directions normal to the oscillation axis. A modulated
voltage (91) is applied in
reverse bias between the n- and p-doped
layers to modulate the
refractive index of the electrooptic material layer (12) and thereby the
reflectivity spectrum of the grating mirror (1). The
reflectivity of the grating mirror (1) can be modulated between a reflectivity with little or no out
coupling and a reflectivity with normal out
coupling, wherein lasing in the VCL is supported at both the first and the second reflectivity. As the out
coupling mirror modulates the output, the lasing does not need to be modulated, and the invention provides the
advantage of lower
power consumption at high modulation speeds.