Light emitting device and super-luminescent diode having layer with first, second, and third waveguides

A light emitting device comprising:

• an active layer;
• and
• a first cladding layer and a second cladding layer sandwiching the active layer,
• wherein the active layer is provided with
• a first gain region having a belt shape extending from a first light emitting section disposed on a first side surface of the active layer to a first light reflecting section disposed on a second side surface of the active layer,
• a second gain region having a belt shape extending from the first light reflecting section to a second light reflecting section disposed on a third side surface of the active layer, and
• a third gain region having a belt shape extending from the second light reflecting section to a second light emitting section disposed on the first side surface,
• an extending direction of the second gain region is parallel to an in-plane direction of the first side surface,
• an element from one of group II or group XII of the periodic table of elements is diffused in the first light reflecting section and the second light reflecting section, and
• a first light emitted from the first light emitting section and a second light emitted from the second light emitting section travel in the same direction.

A super-luminescent diode comprising:

• a first layer that generates light by an injection current;
• and
• a second layer and a third layer that sandwich the first layer and suppress leakage of the light,
• wherein the first layer is provided with
• a first optical waveguide having a belt shape extending from a first light emitting section disposed on a first side surface of the first layer to a first light reflecting section disposed on a second side surface of the first layer,
• a second optical waveguide having a belt shape extending from the first light reflecting section to a second light reflecting section disposed on a third side surface of the first layer, and
• a third optical waveguide having a belt shape extending from the second light reflecting section to a second light emitting section disposed on the first side surface,
• an extending direction of the second optical waveguide is parallel to an in-plane direction of the first side surface,
• an element from one of group II or group XII of the periodic table of elements is diffused in the first light reflecting section and the second light reflecting section, and
• a first light emitted from the first light emitting section and a second light emitted from the second light emitting section travel in the same direction.