Semiconductor laser diode and optical module

A semiconductor laser diode comprising:

• a semiconductor substrate;
• a semiconductor layered body which is formed on the semiconductor substrate and has at least an active region;
• a first electrode provided on the semiconductor substrate at a side opposite to a side on which the semiconductor layered body is formed;
• and
• a second electrode provided at the side of the semiconductor layered body;
• wherein:
• the semiconductor layered body has a semiconductor layered portion on an upper region with respect to the active region thereof, the semiconductor layered portion being in the shape of a projection having its length in a light-propagating direction;
• the second electrode on the semiconductor layered body side contacts at least an upper face of the projected semiconductor layered portion;
• the second electrode on the semiconductor layered body side includes a plurality of conductor layers, the plurality of conductor layers comprising a first conductor layer region which is close to the semiconductor layered body and a second conductor layer region which is formed on the first conductor layer region;
• an insulator film is formed on a portion of at least one of the reflection facets of the laser cavity on the upper face of the projected semiconductor layered portion, side faces of the projected semiconductor layered portion, which are in parallel with the length of the projected semiconductor layered portion, and upper faces of the semiconductor layered body extending outwardly from the side faces;
• the first conductor layer region covers the upper face of the projected semiconductor layered portion and at least a part of the insulator film;
• an edge of the first conductor layer region at the side of at least one of the reflection facets of the laser cavity is recessed inward from the reflection facet of the laser cavity;
• an edge of the second conductor layer region at the side of at least one of the reflection facets of the laser cavity is located at a position identical with the edge position of the first conductor layer region;
• one facet of the insulator film formed on a part of the upper face of the projected semiconductor layered portion is located at a position identical with that of the reflection facet of the laser cavity;
• and
• other facet of the insulator film formed on a part of the upper face of the projected semiconductor layered portion is located at a position identical with or recessed inward from the edge position of the first conductor layer region.

An optical module comprising:

• a substrate;
• a semiconductor laser diode mounted on the substrate;
• and
• a package having in its interior the substrate on which at least the semiconductor laser diode is mounted;
• wherein:
• the semiconductor laser diode comprises
• a semiconductor substrate;
• a semiconductor layered body which is formed on the semiconductor substrate and has at least an active region;
• a first electrode provided on the semiconductor substrate at a side opposite to a side on which the semiconductor layered body is formed;
• and
• a second electrode provided at the side of the semiconductor layered body;
• the semiconductor layered body having a semiconductor layered portion on an upper region with respect to the active region thereof, the semiconductor layered portion being in the shape of a projection having its length in a light-propagating direction;
• the second electrode on the semiconductor layered body side contacting an upper face of the projected semiconductor layered portion;
• and
• the second electrode on the semiconductor layered body side including a plurality of conductor layers, at least one of the conductor layers or a partial region which has a thickness larger than that of an edge of the conductor layer having a facet position of the conductor layer or an end position of the partial region which is thicker than the edge of the conductor layer at a position inside at least one of reflection facets constituting a cavity of the semiconductor laser.