Ratner & Prestia
Semiconductor laser devices
 A semiconductor laser device emits a stable and extremely high optical output. An etching-stop layer is formed at the interface between an active layer and a waveguide layer underlying the active layer, or in a waveguide layer, the layers above the etching-stop layer is processed in a stripe-shaped mesa. Subsequently, a current-blocking layer comprising thin layers of different conductivity type is formed above the etching-stop layer, the thickness of the etching-stop layer being so thin as not to distort the optical intensity distribution of laser light. Alternatively, an active layer and clad layers overlying and underlying the active layer is formed, and a current-blocking layer comprising thin layers of different composition which are alternatively stacked is formed. The conductivity type of the thin layers is reversed at least once during consecutive stacking, and the equivalent refractive index is larger than that of a semiconductor substrate and smaller than that of the mesa. 
Matsushita Electric Industrial Co., Ltd.
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Yoshihiro Nobuyuki
Mori Otsuka