Optical device, modulator module, and method for manufacturing the optical device

1. An optical device comprising:

a ridge-like optical waveguide portion;

a mesa protector portion that is arranged in parallel to the optical waveguide portion;

a resin portion that covers upper parts of the mesa protector portion and is disposed at both sides of the mesa protector portion;

an electrode that is disposed on the optical waveguide portion;

an electrode pad that is disposed on the resin portion located at an opposite side to the optical waveguide portion with respect to the mesa protector portion; and

a connection portion that is disposed on the resin portion and electrically connects the electrode to the electrode pad,

wherein the mesa protector portion is sandwiched between a left part of the resin portion and a right part of the resin portion, and

wherein the connection portion extends from the electrode to the electrode pad passing above the mesa protector portion.

2. The optical device according to claim 1 , wherein a height of the mesa protector portion is greater than a height of the optical waveguide portion.

3. The optical device according to claim 1 , wherein a height of the mesa protector portion is substantially the same as a height of the optical waveguide portion.

4. The optical device according to claim 1 , wherein a width of the mesa protector portion is substantially the same as a height of the optical waveguide portion.

5. The optical device according to claim 1 , wherein the mesa protector portion includes a pair of mesa protectors disposed at both sides of the optical waveguide portion.

6. The optical device according to claim 5 , wherein the resin portion is further disposed between the pair of mesa protectors and the ridge-like optical waveguide portion.

7. The optical device according to claim 1 , wherein the optical waveguide portion includes:

a first optical waveguide that guides incident light;

a first branch portion that branches the light guided by the first optical waveguide;

a plurality of modulation waveguides that modulate and guide the branched light;

a second branch portion that combines the light from the plurality of modulation waveguides; and

a second optical waveguide that guides the light from the second branch portion.

8. A modulator module comprising an optical device, wherein the optical device includes:

a ridge-like optical waveguide portion;

a mesa protector portion that is arranged in parallel to the optical waveguide portion;

a resin portion that covers upper parts of the mesa protector portion and is disposed at both sides of the mesa protector portion;

an electrode that is disposed on the optical waveguide portion;

an electrode pad that is disposed on the resin portion located at an opposite side to the optical waveguide portion with respect to the mesa protector portion; and

a connection portion that is disposed on the resin portion and electrically connects the electrode to the electrode pad,

wherein the mesa protector portion is sandwiched between a left part of the resin portion and a right part of the resin portion, and

wherein the connection portion extends from the electrode to the electrode pad passing above the mesa protector portion.

9. The modulator module according to claim 8 further comprising:

a semiconductor laser that outputs light to the optical device,

wherein the optical device and the semiconductor laser are integrated into the same substrate.

10. The modulator module according to claim 8 , wherein a height of the mesa protector portion is greater than a height of the optical waveguide portion.

11. The modulator module according to claim 8 , wherein a height of the mesa protector portion is substantially the same as a height of the optical waveguide portion.

12. The modulator module according to claim 8 , wherein a width of the mesa protector portion is substantially the same as a height of the optical waveguide portion.

13. The modulator module according to claim 8 , wherein the mesa protector portion includes a pair of mesa protectors disposed at both sides of the optical waveguide portion.

14. The modulator module according to claim 13 , wherein the resin portion is further disposed between the pair of mesa protectors and the ridge-like optical waveguide portion.

15. The modulator module according to claim 8 , wherein the optical waveguide portion includes:

a first optical waveguide that guides incident light;

a first branch portion that branches the light guided by the first optical waveguide;

a plurality of modulation waveguides that modulate and guide the branched light;

a second branch portion that combines the light from the plurality of modulation waveguides; and

a second optical waveguide that guides the light from the second branch portion.

16. A manufacturing method of an optical device comprising:

laminating at least a first clad layer, an active layer, and a second clad layer on a substrate so as to form a laminate structure;

etching the laminate structure so as to form a ridge-like optical waveguide portion and a mesa protector portion arranged in parallel to the optical waveguide portion;

forming a passivation layer on the etched laminate structure and forming a resin portion on the passivation layer; and

forming an electrode portion extending from an upper part of the optical waveguide portion to an upper part of the resin portion located at an opposite side to the optical waveguide portion with respect to the mesa protector portion,

wherein the mesa protector portion is sandwiched between a left part of the resin portion and a right part of the resin portion, and

wherein the electrode portion passes above the mesa protector portion to extend from the upper part of the optical waveguide portion to the upper part of the resin portion.

17. The manufacturing method according to claim 16 , wherein the mesa protector portion includes a pair of mesa protectors, and the resin portion is disposed between the pair of mesa protectors and the ridge-like optical waveguide portion.