| 摘要 |
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 out-coupling 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 between the n- and p-doped layers in reverse bias 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. |
