Semiconductor optical amplifying apparatus

A semiconductor optical amplifying apparatus, comprising:

• a substrate;
• an active layer having a quantum well structure formed on said substrate, said active layer guiding first guided mode light and second guided mode light having a polarization direction perpendicular to that of said first guided mode light and amplifying the guided lights, said active layer having a wave-shape the height of which is less than respective extents of electric field distributions of the guided lights, said wave-shape comprising a plurality of portions in which projected quantization axes adjacent each other, obtained by projecting quantization axes onto a plane perpendicular to a direction to which the guided lights are guided, are not parallel to each other, said plurality of portions being arranged such that a sum of gains to be imparted to the first guided mode light is equal to a sum of gains to be imparted to the second guided mode light;
• and
• an electrode for supplying a current to said active layer.

A semiconductor optical amplifying apparatus comprising:

• a substrate;
• an active layer having a quantum well structure formed on said substrate, said active layer guiding first guided mode light and second guided mode light having a polarization direction perpendicular to that of the first guided mode light and amplifying the guided lights, said active layer having a wave-shape the height of which is less than respective extents of electric field distributions of the guided lights and which includes a plurality of inclined surfaces each of which forms an angle of 45.degree. with respect to each vibration direction of the electric field vectors of the first and second guided mode lights;
• and
• an electrode for supplying a current to said active layer.

A semiconductor optical amplifying apparatus comprising:

• a substrate;
• an active layer having a quantum well structure formed on said substrate, said active layer guiding first guided mode light and second guided mode light having a polarization direction perpendicular to that of the first guided mode light and amplifying the guided lights, said active layer having a wave-shape the height of which is less than respective extents of electric field distributions of the guided lights, said wave-shape comprising a plurality of portions in which adjacent quantum well layers are not parallel to each other, said plurality of portions being arranged such that a sum of gains to be imparted to the first guided mode light is equal to a sum of gains to be imparted to the second guided mode light;
• and
• an electrode for supplying a current to said active layer.

A semiconductor optical amplifying apparatus for guiding light and amplifying the guided light, comprising:

• a substrate consisting of a semiconductor of a first conductivity type and having a flat surface;
• a first cladding layer formed on said flat surface of said substrate and consisting of a semiconductor of the first conductivity type, said first cladding layer having a wave-shape in a direction perpendicular to a direction to which the guided lights are guided on the upper side thereof, the height of the wave-shape being less than respective extents of electric field distributions of the guided lights, the wave-shape comprising a plurality of surfaces which are periodically provided, the adjacent surfaces being not parallel to each other;
• a semiconductor active layer having a quantum well structure formed on said wave-shape of said first cladding layer;
• a second cladding layer formed on said active layer and consisting of a semiconductor of a second conductivity type;
• a first electrode formed on said second cladding layer;
• and
• a second electrode contacting said substrate.