Heater-integrated ridge type optical semiconductor optical device
A ridge type semiconductor optical device includes a first conductivity type semiconductor layer including at least a first stripe section; an active layer including at least an active stripe section on the first stripe section; a second conductivity type semiconductor layer including at least a second stripe section on the active stripe section; a ridge electrode on the second stripe section; an insulation film on an end face of each of the first stripe section, the active stripe section, and the second stripe section; and a film heater on the insulation film, the film heater overlapping with the end face of at least the first stripe section.
1. A ridge type semiconductor optical device, comprising:
a first conductivity type semiconductor layer including at least a first stripe section;
an active layer including at least an active stripe section on the first stripe section;
a second conductivity type semiconductor layer including at least a second stripe section on the active stripe section;
a ridge electrode on the second stripe section;
an insulation film on an end face of each of the first stripe section, the active stripe section, and the second stripe section; and
a film heater on the insulation film, the film heater overlapping with the end face of at least the first stripe section.
2. The ridge type semiconductor optical device of claim 1 , wherein the film heater is configured to overlap with the end face of the active stripe section.
3. The ridge type semiconductor optical device of claim 2 , wherein the second stripe section is composed of multiple layers including a lower layer and an upper layer, the upper layer being narrower in width than the lower layer and constituting at least part of a mesa stripe structure, and
the film heater is configured to overlap with an end face of the lower layer of the second stripe section.
4. The ridge type semiconductor optical device of claim 3 , wherein the film heater is configured to overlap with an upper surface edge of the lower layer of the second stripe section.
5. The ridge type semiconductor optical device of claim 1 , wherein
the first conductivity type semiconductor layer includes another portion spaced from the end face of the first stripe section,
the active layer includes another portion spaced from the end face of the active stripe section,
the second conductivity type semiconductor layer includes another portion spaced from the end face of the second stripe section, and
an isolation trench is formed to have an inner surface, part of which is the end face.
6. The ridge type semiconductor optical device of claim 5 , further comprising:
a semiconductor substrate under the first conductivity type semiconductor layer,
wherein the isolation trench has a bottom in the semiconductor substrate.
7. The ridge type semiconductor optical device of claim 5 , further comprising:
a pair of heater draw-out lines connected to respective both ends of the film heater, extending in a direction away from the film heater, and passing through the inner surface of the isolation trench; and
a ridge draw-out line connected to the ridge electrode, extending in a direction away from the ridge electrode, and passing through the inner surface of the isolation trench.
8. The ridge type semiconductor optical device of claim 7 , wherein
each of the pair of heater draw-out lines is a laminate of parts of respective layers of a conductive multilayer films, and
the film heater is part of all but at least one layer of the conductive multilayer films.
9. The ridge type semiconductor optical device of claim 7 , wherein a draw-out direction of the pair of heater draw-out lines from the film heater is opposite to a draw-out direction of the ridge draw-out line from the ridge electrode.
10. The ridge type semiconductor optical device of claim 7 , wherein
the isolation trench includes a first isolation trench and a second isolation trench, the first isolation trench and the second isolation trench being formed on both sides of the first stripe section, the active stripe section, and the second stripe section,
the end face includes a first end face and a second end face, each of the first end face and the second end face being part of the inner surface of a corresponding of the first isolation trench and the second isolation trench, and
the film heater includes a first film heater and a second film heater, the first film heater and the second film heater overlapping with the first end face and second end face, respectively.
11. The ridge type semiconductor optical device of claim 10 , wherein the first film heater and the ridge draw-out line are electrically insulated and intersect with each other.
12. The ridge type semiconductor optical device of claim 10 , wherein the first film heater and the second film heater are connected in series.
13. The ridge type semiconductor optical device of claim 12 , wherein
the second film heater is composed of a pair of second film heaters that are separated, and
the first film heater is connected in series between the pair of second film heaters.
14. The ridge type semiconductor optical device of claim 1 , wherein the film heater has a lower surface, which is made of titanium, in close-fitting with the insulation film.