Semiconductor laser device

摘要

Disclosed is a semiconductor laser device having at least an optical confinement region which includes a first semiconductor layer, and second and third semiconductor layers holding the first semiconductor layer therebetween and having a greater band gap and a lower refractive index than those of the first semiconductor layer, the second and third semiconductor layers having conductivity types opposite to each other; characterized in that the relationship between a donor density (NDx1017 cm-3) of the n-conductivity type semiconductor layer in the second and third semiconductor layers and a proportion ( GAMMA n%) of an optical output existing in the n-conductivity type semiconductor layer relative to a total optical output of the laser is set at NDx GAMMA n>/=500. Noise characteristics are sharply improved.