Distributed feedback semiconductor laser device and multi-wavelength laser array

A multi-wavelength laser array, comprising:

• a common substrate, and
• a plurality of ridge waveguide type semiconductor laser devices disposed in an array overlying the common substrate, wherein each of the semiconductor laser devices includes
• an active layer,
• a diffraction grating disposed directly or indirectly on top of or below the active layer and having a substantially uniform space period and a distributed feedback function, and
• a refractive index control layer disposed directly or indirectly on top of both the diffraction grating and the active layer, said refractive index control layer configured to control a refractive index of an emission region of the active layer in a horizontal direction.

A ridge waveguide type distributed feedback semiconductor laser device, comprising:

• an active layer,
• a diffraction grating disposed directly or indirectly on top of or below the active layer and having a substantially uniform space period and a distributed feedback function, and
• a refractive index control layer disposed directly or indirectly on top of both the diffraction grating and the active layer, said refractive index control layer configured to control a refractive index of an emission region of the active layer in a horizontal direction said refractive index control layer comprising a non-Al oxide layer and a pair of Al oxide layers consecutively extending from both sides of the non-Al oxide layer along the active layer, wherein
• the refractive index of the emission region of the active layer depends on widths of the non-Al oxide layer in an extending direction of the active layer.

A multi-wavelength laser stray, comprising:

• a common substrate;
• and
• a plurality of ridge wave guide type semiconductor laser devices disposed in an array overlying the common substrate, wherein each of the semiconductor laser devices includes
• an active layer,
• a diffraction grating disposed directly or indirectly on top of or below the active layer and having a substantially uniform space period and a distributed feedback function, and
• a refractive index control layer disposed directly or indirectly on top of both the diffraction gating and the active layer, said refractive index control layer configured to control a refractive index of an emission region of the active layer in a horizontal direction, said refractive index control layer comprising a non-Al oxide layer and a pair of Al oxide layers consecutively extending from both sides of the non-Al oxide layer along the active layer, wherein
• the refractive index of the omission region of the active layer depends on widths of the non-Al oxide layer in an extending direction of the active layer.