Semiconductor laser device

A semiconductor laser device comprising:

• a semiconductor substrate;
• a resonator structure including an active layer overlying said semiconductor substrate and including an absorption region disposed adjacent to the active layer in a laminated structure including said active layer;
• and
• a wavelength selecting structure formed above said active layer and configured to select a lasing wavelength λe independent of an optical gain distribution of said active layer,
• wherein said absorption region is made of a compound semiconductor layer having an absorption coefficient λmax with respect to a peak wavelength λmax of said optical gain distribution of said active layer which exceeds an absorption coefficient αe of said absorption region with respect to said lasing wavelength λe,
• wherein a bandgap wavelength λg of said absorption region and said lasing wavelength λe satisfy 0<λe−λg<100 nm.

A semiconductor laser device comprising:

• a semiconductor substrate;
• a resonator structure including an active layer overlying said semiconductor substrate and including an absorption region disposed adjacent to the active layer in a laminated structure including said active layer;
• and
• a wavelength selecting structure formed above said active layer and configured to select a lasing wavelength λe independent of an optical gain distribution of said active layer, wherein said absorption region is made of a compound semiconductor layer having an absorption coefficient αmax with respect to a peak wavelength λmax of said optical gain distribution of said active layer which exceeds an absorption coefficient αe of said absorption region with respect to said lasing wavelength λe,
• wherein said absorption region satisfies αmax−αe≧1 cm−1 in terms of waveguide loss, and
• wherein αe is substantially zero in said absorption region.

A semiconductor laser device comprising:

• a semiconductor substrate;
• a resonator structure including an active layer overlying said semiconductor substrate and including an absorption region disposed adjacent to the active layer in a laminated structure including said active layer;
• and
• a wavelength selecting structure formed above said active layer and configured to select a lasing wavelength λe independent of an optical gain distribution of said active layer,
• wherein said absorption region is made of a compound semiconductor layer,
• wherein a bandgap wavelength λg of said absorption region and said lasing wavelengthλe satisfy 0<λe−λg≦100 nm,
• wherein said absorption region satisfies αmax−αe≧1 cm−1 in terms of waveguide loss, and
• wherein αe is substantially zero in said absorption region.